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Diagnostic yield of MR myelography in patients with newly diagnosed spontaneous intracranial hypotension: a systematic review and meta-analysis
Abstract
Objectives:
To investigate the pooled diagnostic yield of MR myelography in patients with newly diagnosed spontaneous intracranial hypotension (SIH).
Methods:
A literature search of the MEDLINE/PubMed and Embase databases was conducted until July 25, 2021, including studies with the following inclusion criteria: (a) population: patients with newly diagnosed SIH; (b) diagnostic modality: MR myelography or MR myelography with intrathecal gadolinium for evaluation of CSF leakage; (c) outcomes: diagnostic yield of MR myelography or MR myelography with intrathecal gadolinium. The risk of bias was evaluated using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. DerSimonian-Laird random-effects modeling was used to calculate the pooled estimates. Subgroup analysis regarding epidural fluid collection and meta-regression were additionally performed.
Results:
Fifteen studies with 643 patients were included. Eight studies used MR myelography with intrathecal gadolinium, and 11 used MR myelography. The overall quality of the included studies was moderate. The pooled diagnostic yield of MR myelography was 86% (95% CI, 80-91%) and that of MR myelography with intrathecal gadolinium was 83% (95% CI, 51-96%). There was no significant difference in pooled diagnostic yield between MR myelography and MR myelography with intrathecal gadolinium (p = 0.512). In subgroup analysis, the pooled diagnostic yield of the epidural fluid collection was 91% (95% CI, 84-94%). In meta-regression, the diagnostic yield was unaffected regardless of consecutive enrollment, magnet strength, or 2D/3D.
Conclusions:
MR myelography had a high diagnostic yield in patients with SIH. MR myelography is non-invasive and not inferior to MR myelography with intrathecal gadolinium.
Key points:
• The pooled diagnostic yield of MR myelography was 86% (95% CI, 80-91%) in patients with spontaneous intracranial hypotension. • There was no significant difference in pooled diagnostic yield between MR myelography and MR myelography with intrathecal gadolinium. • MR myelography is non-invasive and not inferior to MR myelography with intrathecal gadolinium.
... Although MRM without contrast administration is a static examination that has limited ability to delineate the dynamic process of CSF egress from the dural sac, it can be used to demonstrate CSF collections, especially when acquired with heavily T2weighted (HT2W) MRI, a fluid-sensitive sequence (7,8). HT2W sequences without intrathecal contrast were shown to be comparable to CT myelography and noninferior to MRM with intrathecal contrast in detecting extradural CSF collections, and appear to be ubiquitous across multiple studies on MRM (8)(9)(10)(11). ...
... HT2W-FS MRM has advantages over CT myelography or MRM with intrathecal gadolinium in that it avoids radiation exposure, adverse effects of contrast media, and lumbar punctures (10). Previous investigations using 3D fatsaturated T2WI or HT2W MRM showed accurate epidural fluid detection in patients with intracranial hypotension compared with CT myelography with intrathecal contrast (95% detection rate) or radionuclide cisternography (81.5%) (9,27). ...
Background
Heavily T2-weighted fat-saturated (HT2W-FS) magnetic resonance myelography (MRM) is useful for diagnosing the cause of intracranial hypotension. Recently, deep learning-based reconstruction (DLR) has been utilized to improve image signal-to-noise ratios and sharpness while reducing artifacts, all without lengthening acquisition times. This study aimed to compare the diagnostic performance and image quality of conventional reconstruction (CR) and DLR of 3-dimensional (3D) HT2W-FS MRM applied to detecting epidural fluid in patients with clinically suspected intracranial hypotension.
Methods
This retrospective study included 21 magnetic resonance myelography examinations using both CR and DLR in 21 patients who experienced orthostatic headache between April 2021 and September 2022. Quantitative image quality evaluation was performed by comparing signal-to-noise ratios at the lower thoracic levels. The image quality and artifacts were graded by three readers. The presence of epidural fluid was reported with a confidence score by two readers, and the area under the receiver operating curve, interobserver agreement, and inter-image-set agreement were evaluated. The conspicuity of the dura mater where the epidural fluid was detected was also investigated.
Results
Quantitative and subjective image quality, and artifacts significantly improved with DLR (all P<0.001). Diagnostic performance of DLR was higher for both readers [reader 1: area under the curve (AUC) of CR =0.929; 95% confidence interval (CI): 0.902–0.950, AUC of DLR =0.965 (95% CI: 0.944–0.979), P=0.007; reader 2: AUC of CR =0.834 (95% CI: 0.798–0.866), AUC of DLR =0.877 (0.844–0.905), P=0.040]. Correlation with standard care of MRM in CR and DLR were both strong in reader 1 (rho =0.868–0.919, P<0.001), but was respectively strong and moderate in reader 2 (rho =0.734–0.805, P<0.001). Interobserver agreement was substantial (κ=0.708–0.762). The inter-image-set agreement was almost perfect for reader 1 (κ=0.907) and was substantial for reader 2 (κ=0.750). Dura mater conspicuity significantly improved with DLR (P<0.014, reader 1; P<0.001, readers 2 and 3).
Conclusions
HT2W-FS magnetic resonance myelography with DLR demonstrates substantial improvements in image quality and may improve confidence in detecting epidural fluid.
... In addition, MR myelography has a non-inferior diagnostic rate compared with intrathecal gadolinium-injection MR myelography. 15 We had planned to proceed with early mobilization if there was no cerebrospinal fluid leakage, but this was not possible because of the restriction of the patient's movements due to the vertebral body fracture. MR myelography is non-invasive, easy to use, and can be used to evaluate vertebral body fractures; therefore, if pneumorrhachis associated with vertebral trauma is diagnosed, MR myelography should be considered. ...
Attention should be paid to cerebrospinal fluid leakage in patients with pneumorrhachis associated with vertebral body trauma. If pneumorrhachis is detected, further imaging investigation and bed rest should be considered as appropriate.
Spontaneous intracranial hypotension (SIH) remains an underdiagnosed condition despite increasing awareness due to recent scientific advances. Diagnosis can be delayed by the broad clinical presentation and imaging pitfalls. This results in a high degree of physical impairment for patients, including social and psychological sequelae as well as long-term damage in the case of delayed diagnosis and treatment.
The study is based on a selective literature search on PubMed including articles from 1990 to 2023 and the authors’ clinical experience from working in a CSF center.
SIH mostly affects middle-aged women, with the primary symptom being position-dependent orthostatic headache. In addition, there is a broad spectrum of possible symptoms that can overlap with other clinical conditions and therefore complicate the diagnosis. The causative spinal CSF loss can be divided into three main types: ventral (type 1) or lateral (type 2) dural leak and CSF-venous fistula (type 3). The diagnosis can be made using a two-stage workup. As a first step, noninvasive MRI of the head and spine provides indicators of the presence of SIH. The second step using focused myelography can identify the exact location of the cerebrospinal fluid leak and enable targeted therapy (surgical or interventional). Intrathecal pressure measurement or intrathecal injection of gadolinium is no longer necessary for primary diagnosis. Serious complications in the course of the disease can include space-occupying subdural hematomas, superficial siderosis, and symptoms of brain sagging, which can lead to misinterpretations. Treatment consists of closing the dural leak or the cerebrospinal fluid fistula. Despite successful treatment, a relapse can occur, which highlights the importance of follow-up MRI examinations and emphasizes the chronic nature of the disease. This paper provides an overview of the diagnostic workup of patients with suspected SIH and new developments in imaging and therapy.
Primary intracranial pressure disorders include idiopathic intracranial hypertension and spontaneous intracranial hypotension. These two entities have presented a remarkable advance in diagnostic and therapeutic techniques in recent years. Therefore, the Spanish Society of Neurology's Headache Study Group (GECSEN) considered it necessary to prepare this consensus document with the inclusion of diagnostic and therapeutic algorithms to facilitate and improve their management in clinical practice. This document was created by a committee of experts of the GECSEN based on a systematic review of the literature, incorporating the experience of the participants, and establishing practical recommendations with levels of evidence and grades of recommendation.
Background
To develop and validate an easy-to-use scoring system to predict the response to the first epidural blood patching in patients with spontaneous intracranial hypotension.
Methods
This study recruited consecutive patients with spontaneous intracranial hypotension receiving epidural blood patching in a tertiary medical center, which were chronologically divided into a derivation cohort and a validation cohort. In the derivation cohort, factors associated with the first epidural blood patching response were identified by using multivariable logistic regression modeling. A scoring system was developed, and the cutoff score was determined by using the receiver operating characteristic curve. The findings were verified in an independent validation cohort.
Results
The study involved 280 patients in the derivation cohort and 78 patients in the validation cohort. The spontaneous intracranial hypotension-epidural blood patching score (range 0–5) included two clinical variables (sex and age) and two radiological variables (midbrain-pons angle and anterior epidural cerebrospinal fluid collections). A score of ≥3 was predictive of the first epidural blood patching response, which was consistent in the validation cohort. Overall, patients who scored ≥3 were more likely to respond to the first epidural blood patching (odds ratio = 10.3).
Conclusion
For patients with spontaneous intracranial hypotension-epidural blood patching score ≥3, it is prudent to attempt at least one targeted epidural blood patching before considering more invasive interventions.
Objective:
To evaluate the completeness of the reporting of systematic reviews and meta-analyses published in a general radiology journal using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines.
Materials and methods:
Twenty-four articles (systematic review and meta-analysis, n = 18; systematic review only, n = 6) published between August 2009 and September 2021 in the Korean Journal of Radiology were analyzed. Completeness of the reporting of main texts and abstracts were evaluated using the PRISMA 2020 statement. For each item in the statement, the proportion of studies that met the guidelines' recommendation was calculated and items that were satisfied by fewer than 80% of the studies were identified. The review process was conducted by two independent reviewers.
Results:
Of the 42 items (including sub-items) in the PRISMA 2020 statement for main text, 24 were satisfied by fewer than 80% of the included articles. The 24 items were grouped into eight domains: 1) assessment of the eligibility of potential articles, 2) assessment of the risk of bias, 3) synthesis of results, 4) additional analysis of study heterogeneity, 5) assessment of non-reporting bias, 6) assessment of the certainty of evidence, 7) provision of limitations of the study, and 8) additional information, such as protocol registration. Of the 12 items in the abstract checklists, eight were incorporated in fewer than 80% of the included publications.
Conclusion:
Several items included in the PRISMA 2020 checklist were overlooked in systematic review and meta-analysis articles published in the Korean Journal of Radiology. Based on these results, we suggest a double-check list for improving the quality of systematic reviews and meta-analyses. Authors and reviewers should familiarize themselves with the PRISMA 2020 statement and check whether the recommended items are fully satisfied prior to publication.
Purpose
Intrathecal gadolinium magnetic resonance (MR) myelography can be used to localize various types of spinal cerebrospinal fluid (CSF) leaks; however, its diagnostic yield is not well known. We sought to determine the diagnostic yield of MR myelography in patients with spontaneous intracranial hypotension.
Methods
A retrospective review was performed on all patients who had undergone intrathecal gadolinium MR myelography at our institution from 2002 to 2020 for suspected spinal CSF leak. The MR myelography images were reviewed for the presence or absence of a spinal CSF leak site. Images were also evaluated for the presence an extradural fluid collection.
Results
A total of 97 patients were included in the final cohort. The average age was 52.6 years; 67.0% were female, 4 patients underwent 2 examinations each, yielding a total of 101 MR myelograms. The source of a spinal CSF leak was localized in 14 patients. The diagnostic yield for CSF leak localization on intrathecal gadolinium MR myelography was 14/101 (13.9%) per GdM examination and 14/97 (14.4%) per patient. Among the subset of patients without extradural fluid collections, the yield was 15.7% per examination. All detected leaks were either CSF-venous fistulas or distal nerve root sleeve tears.
Conclusion
Intrathecal gadolinium MR myelography is capable of localizing CSF-venous fistulas and distal nerve root sleeve tears; however, our data show that it has a limited diagnostic yield. We suggest that other modalities may be a better first step before attempting intrathecal gadolinium MR myelography.
Purpose
To evaluate the clinical utility of intravenous gadolinium-enhanced heavily T2-weighted 3D fluid-attenuated inversion recovery (HT2-FLAIR) imaging for identifying spinal cerebrospinal fluid (CSF) leaks in patients with spontaneous intracranial hypotension (SIH).
Methods
Patients with SIH underwent MR myelography and post-contrast HT2-FLAIR imaging after an intravenous gadolinium injection. Two types of CSF leaks (epidural fluid collection and CSF leaks around the nerve root sleeve) at each vertebral level were compared between the 2 sequences. The total numbers of CSF leaks and vertebral levels involved were recorded for the whole spine. The sequence that was superior for the overall visualization of epidural and paraspinal fluid collection was then selected.
Results
Nine patients with SIH were included in the present study. HT2-FLAIR imaging was equivalent or superior to MR myelography at each level for detecting the 2 types of CSF leaks. In the 2 types of CSF leaks, the total numbers of CSF leaks and levels involved were higher on HT2-FLAIR images than on MR myelography, while no significant difference was observed for CSF leaks around the nerve root sleeve. In all 9 patients, HT2-FLAIR imaging was superior to MR myelography for the overall visualization of epidural and paraspinal fluid collection.
Conclusion
Intravenous gadolinium-enhanced HT2-FLAIR imaging was superior to MR myelography for the visualization of CSF leaks in patients with SIH. This method can be useful for identifying spinal CSF leaks.
The methods and results of systematic reviews should be reported in sufficient detail to allow users to assess the trustworthiness and applicability of the review findings. The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement was developed to facilitate transparent and complete reporting of systematic reviews and has been updated (to PRISMA 2020) to reflect recent advances in systematic review methodology and terminology. Here, we present the explanation and elaboration paper for PRISMA 2020, where we explain why reporting of each item is recommended, present bullet points that detail the reporting recommendations, and present examples from published reviews. We hope that changes to the content and structure of PRISMA 2020 will facilitate uptake of the guideline and lead to more transparent, complete, and accurate reporting of systematic reviews.
Spontaneous intracranial hypotension, the classic feature of which is orthostatic headache, is most commonly caused by a cerebrospinal fluid leakage at the level of the spinal canal, in most cases at the thoracic level or cervicothoracic junction. Underlying connective tissue disorders, minor trauma, degenerative spinal diseases may play a role in the development of cerebrospinal fluid leaks. Traction on pain-sensitive intracranial and meningeal structures, particularly sensory nerves and bridging veins, may play a role in the development of orthostatic headache. In the case of patients with classic orthostatic headache, the possibility of spontaneous intracranial hypotension should be considered, and if suspected, brain magnetic resonance imaging (MRI) with gadolinium and additional spine MRI are recommended. Diffuse, non-nodular, intense, thick dural enhancement, subdural effusions, engorgement of cerebral venous sinuses, sagging of the brain are typical features on brain MRI, which, however, remain normal in up to 20 percent of patients with spontaneous intracranial hypotension. Unfortunately, no randomized clinical trials have evaluated the effectiveness of the various treatment strategies and no definitive treatment protocols have been established. In clinical practice, the first-line treatment of spontaneous intracranial hypotension is conservative (bed rest, caffeine and fluid intake). If conservative therapy is not effective, epidural blood patch, epidural fibrin glue, or surgical repair should be considered.
Importance
Spontaneous intracranial hypotension (SIH) is a highly disabling but often misdiagnosed disorder. The best management options for patients with SIH are still uncertain.
Objective
To provide an objective summary of the available evidence on the clinical presentation, investigations findings, and treatment outcomes for SIH.
Data Sources
Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline–compliant systematic review and meta-analysis of the literature on SIH. Three databases were searched from inception to April 30, 2020: PubMed/MEDLINE, Embase, and Cochrane. The following search terms were used in each database: spontaneous intracranial hypotension, low CSF syndrome, low CSF pressure syndrome, low CSF volume syndrome, intracranial hypotension, low CSF pressure, low CSF volume, CSF hypovolemia, CSF hypovolaemia, spontaneous spinal CSF leak, spinal CSF leak, and CSF leak syndrome.
Study Selection
Original studies in English language reporting 10 or more patients with SIH were selected by consensus.
Data Extraction and Synthesis
Data on clinical presentation, investigations findings, and treatment outcomes were collected and summarized by multiple observers. Random-effect meta-analyses were used to calculate pooled estimates of means and proportions.
Main Outcomes and Measures
The predetermined main outcomes were the pooled estimate proportions of symptoms of SIH, imaging findings (brain and spinal imaging), and treatment outcomes (conservative, epidural blood patches, and surgical).
Results
Of 6878 articles, 144 met the selection criteria and reported on average 53 patients with SIH each (range, 10-568 patients). The most common symptoms were orthostatic headache (92% [95% CI, 87%-96%]), nausea (54% [95% CI, 46%-62%]), and neck pain/stiffness (43% [95% CI, 32%-53%]). Brain magnetic resonance imaging was the most sensitive investigation, with diffuse pachymeningeal enhancement identified in 73% (95% CI, 67%-80%) of patients. Brain magnetic resonance imaging findings were normal in 19% (95% CI, 13%-24%) of patients. Spinal neuroimaging identified extradural cerebrospinal fluid in 48% to 76% of patients. Digital subtraction myelography and magnetic resonance myelography with intrathecal gadolinium had high sensitivity in identifying the exact leak site. Lumbar puncture opening pressures were low, normal (60-200 mm H2O), and high in 67% (95% CI, 54%-80%), 32% (95% CI, 20%-44%), and 3% (95% CI, 1%-6%), respectively. Conservative treatment was effective in 28% (95% CI, 18%-37%) of patients and a single epidural blood patch was successful in 64% (95% CI, 56%-72%). Large epidural blood patches (>20 mL) had better success rates than small epidural blood patches (77% [95% CI, 63%-91%] and 66% [95% CI, 55%-77%], respectively).
Conclusions and Relevance
Spontaneous intracranial hypotension should not be excluded on the basis of a nonorthostatic headache, normal neuroimaging findings, or normal lumbar puncture opening pressure. Despite the heterogeneous nature of the studies available in the literature and the lack of controlled interventional studies, this systematic review offers a comprehensive and objective summary of the evidence on SIH that could be useful in guiding clinical practice and future research.
Objectives:
In the present study, the authors presented the intrathecal gadolinium enhanced MR-myelography findings of patients with spontaneous intracranial hypotension.
Materials and methods:
Intrathecal gadolinium enhanced MR-myelography (Gd-MR-myelography) examinations between October 2012 and September 2018 in patients having clinical and radiological findings of spontaneous intracranial hypotension were evaluated retrospectively. Sites and types of contrast leakages in 20 patients who met inclusion criteria were reviewed. All patients had undergone T1-fat suppressed sagittal images of cervical, thoracic and lumbar region after the off label intrathecal injection of 1 ml gadolinium-based contrast agent.
Results:
Patients (18 female, 2 male) are aged between 23 and 62 years-old (mean age: 41.1). Cerebrospinal fluid (CSF) leakages were cervical in 6 patients, thoracic in 5 patients, lumbar in 5 patients. One patient had leakage in multiple levels on both cervical and thoracic region and another patient on both cervical-thoracic and lumbar regions. No patients had adverse effects related to intrathecal injection of gadolinium.
Conclusions:
Gd-MR-myelography is effective imaging modality to reveal spinal CSF leakages in patients with spontaneous intracranial hypotension.
Background and purpose: Spontaneous intracranial hypotension (SIH) is a significant, treatable cause of postural headache, although the best diagnostic approach to diagnosing cerebrospinal fluid (CSF) leaks remains uncertain. The aim of this study is to evaluate the most common techniques used to diagnose leaks, the most frequent leak sites, and epidural patch treatment characteristics. Materials and methods: We retrospectively reviewed the electronic medical records and radiographic findings of 30 patients clinically treated for SIH at a single university hospital between January 2015 and December 2016. Clinical symptoms, imaging findings and epidural patch details including dates, injection location, and amount of blood/fibrin injected were recorded. Results: Of 30 SIH patients identified, 11/30 (37%) had a localized leak and 14/30 (47%) had a non-localized leak. The first modality to identify the leak was most commonly CT myelogram (17/25, 68%), followed by MRI spine (6/25, 24%) and MRI myelogram (2/25, 8%). The most frequent leak sites were C7–T1, C5–C6, and T10–T11 in decreasing order. All patients underwent CT-guided epidural patch, averaging 2.3 procedure sessions, 3.4 injection sites, and 7.8 mL of injectate per site. Conclusion: Spinal CSF leak remains a challenging diagnosis, with CT myelography most frequently confirming the diagnosis, supplemented by spine MRI and MRI myelography. Patients frequently require multiple injections at multiple sites, and physicians and patients should be aware of the possible need for repeat treatments. Given the most common sites of leak, empiric blood patch at the cervicothoracic or thoracolumbar junction should be considered if no definitive leak is identified. Keywords: Headache, Cerebrospinal fluid leak, Blood patch
Background Updated guidelines for suspected primary central nervous system lymphoma (PCNSL) are lacking. Purpose To investigate the diagnostic yield of initial systemic imaging in patients suspected of having PCNSL by using contrast material-enhanced chest and abdominopelvic CT and/or whole-body fluorine 18 fluorodeoxyglucose (FDG) PET/CT. Materials and Methods This retrospective study included 304 patients examined at a single tertiary hospital between January 1998 and October 2018. Consecutive adults (age >18 years) who were confirmed to have newly diagnosed PCNSL on the basis of findings at stereotactic brain biopsy were recruited. All patients were examined with contrast-enhanced chest and abdominopelvic CT and/or whole-body FDG PET/CT before initiation of PCNSL treatment. The diagnostic yield of CT and PET/CT was determined before therapy and at the time of recurrence in the brain. A χ2 test was performed to compare the diagnostic yield according to study date in order to assess for possible changes in technology during the study period. Results A total of 304 patients (180 men with a mean age [±standard deviation] of 58 years ± 13 and 124 women with a mean age of 59 years ± 13) were included. The diagnostic yield of CT and PET/CT for initial staging was 2% (six of 304 patients; 95% confidence interval [CI]: 0.7%, 4.3%), and these tests yielded false-positive findings in 13 of the 304 patients (4%; 95% CI: 2.3%, 7.2%). Diagnostic yield did not differ between patients evaluated before 2009 and those evaluated in 2009 and later (P = .82). The diagnostic yield of systemic imaging at recurrence was 1.5% (one of 68 patients; 95% CI: 0.0%, 7.9%), and these tests yielded false-positive findings in four of those 68 patients (6%; 95% CI: 1.6%, 14.4%). Conclusion Contrast-enhanced chest and abdominopelvic CT and/or whole-body fluorine 18 fluorodeoxyglucose PET/CT for initial staging, as well as for recurrence of suspected primary central nervous system lymphoma, had a low diagnostic yield. © RSNA, 2019 See also the editorial by Jara in this issue.
Background:
Diagnosis of spontaneous intracranial hypotension (SIH) relies on the ability of medical staff to recognize cerebrospinal fluid (CSF) leakage at the spine. However, difficulties with interobserver discrepancy sometimes occurred while reading magnetic resonance myelography (MRM) because clear image definition was lacking. In this study, we tried to determine which pattern of CSF distribution is more reliable for diagnosis of CSF leakage by using MRM.
Methods:
From January 2012 to August 2014, 19 SIH patients and 27 healthy controls (HC) were recruited into our study; 10 of the 19 patients were recovered (SIH-R) after treatment. Whole spine MRM was performed using the 3D-SPACE (three-dimensional sampling perfection with application-optimized contrasts using different flip-angle evolutions) sequence, and interpreted by two experienced neuroradiologists. Two 4-point classification systems of CSF distribution were used to evaluate the three-dimensional maximum intensity projection (3D MIP) and the thin-slice axial multiplanar reconstruction (MPR) images, respectively.
Results:
The interobserver agreement between the two readers interpreting the 3D MIP and thin-slice axial MPR MRM were moderate to good (κ=0.60-0.78). Grade 3 of 3D MIP and Type D of axial MPR MRM were only noticed in the SIH. Overall, Grade 3 of MIP and Type D of MPR showed significant difference (p<0.008) between the SIH and the HC in the whole spine. Type C at the T-spine was more frequently noted in the SIH than in the HC (p<0.038). By using "Grade 3", "Type D", "Type D and Type C at T-spine" as the diagnostic criteria of CSF leakage, the sensitivity, specificity, positive predict value (PPV), and negative predict value (NPV) were all > 70%.
Conclusion:
Grade 3 on 3D MIP and Type D on axial MPR MRM were definite criteria of MRM for localizing CSF leakage, and Type C in the T-spine was a probable leakage sign with high sensitivity and NPV.
Meta-analysis of diagnostic test accuracy studies differs from the usual meta-analysis of therapeutic/interventional studies in that, it is required to simultaneously analyze a pair of two outcome measures such as sensitivity and specificity, instead of a single outcome. Since sensitivity and specificity are generally inversely correlated and could be affected by a threshold effect, more sophisticated statistical methods are required for the meta-analysis of diagnostic test accuracy. Hierarchical models including the bivariate model and the hierarchical summary receiver operating characteristic model are increasingly being accepted as standard methods for meta-analysis of diagnostic test accuracy studies. We provide a conceptual review of statistical methods currently used and recommended for meta-analysis of diagnostic test accuracy studies. This article could serve as a methodological reference for those who perform systematic review and meta-analysis of diagnostic test accuracy studies.
In the field of diagnostic test accuracy (DTA), the use of systematic review and meta-analyses is steadily increasing. By means of objective evaluation of all available primary studies, these two processes generate an evidence-based systematic summary regarding a specific research topic. The methodology for systematic review and meta-analysis in DTA studies differs from that in therapeutic/interventional studies, and its content is still evolving. Here we review the overall process from a practical standpoint, which may serve as a reference for those who implement these methods.
Object:
The purpose of this study was to describe significant CT myelography findings for determination of the leak site and outcome of targeted epidural blood patch (EBP) in patients with spontaneous CSF leaks.
Methods:
During 2005-2013, spontaneous CSF leaks were diagnosed for 12 patients with orthostatic headaches. The patients received targeted EBP on the basis of CT myelography assessments.
Results:
Computed tomography myelograms revealed ventral extradural collection of contrast medium distributed over multiple spinal levels (average 16 levels). Intraforaminal contrast medium extravasations were observed at multiple spinal levels (average 8.2 levels). For 8 (67%) of 12 patients, spinal lesions were noted around the thecal sac and included calcified discs with osteophytes, an ossified posterior longitudinal ligament, and an ossified yellow ligament; lesions were mostly located ventral to the thecal sac and were in close contact with the dura mater. The levels of these spinal lesions were considered potential leak sites and were targeted for EBP. For the remaining 4 patients who did not have definite spinal lesions around the thecal sac, leak site determination was based primarily on the contrast gradient hypothesis. The authors hypothesized that the concentration of extradural contrast medium would be the greatest and the same as that of intradural contrast medium at the leak site but that it would decrease with increased distance from the leak site according to the contrast gradient. Epidural blood patch was placed at the level of spinal lesions and/or of the greatest and same concentration of contrast medium between the intradural and extradural spaces. For 10 of the 12 patients, the orthostatic headaches decreased significantly within a week of EBP and disappeared within a month. For the remaining 2 patients, headaches persisted and medical treatment was required for several months. For 3 patients, thick chronic subdural hematomas caused severe headaches and/or disturbed consciousness because of the mass effect of the hematomas, which were removed by bur hole drainage surgery. For 1 patient, bur hole drainage before EBP on the day of admission to hospital resulted in subdural tension pneumocephalus. The patient's headache immediately disappeared after EBP, and the hematoma did not recur. The other 2 patients underwent EBP followed by bur hole drainage, which resulted in improvements and disappearance of the hematomas. Over the follow-up period (mean 39 months), no CSF leaks or chronic subdural hematomas had recurred in any patient after EBP; by the final follow-up visit, all patients had returned to their jobs.
Conclusions:
The most significant finding of this study was that spinal ventral calcified or ossified lesions, which may be associated with a dural tear, were present in approximately 70% of patients. Targeted EBP to these lesions resulted in good outcomes.
To the Editor In an article in JAMA Neurology, Papadopoulou et al1 demonstrated that intrathecal gadolinium–enhanced magnetic resonance (MR) myelography provided clear evidence of dural leaks along 2 lumbar roots in a case of spontaneous intracranial hypotension. Results from a previous radioisotope cisternography had been inconclusive in revealing these leaks, while an MR image of the spinal cord showed a small lumbar perineural cyst with no evidence of cerebrospinal fluid (CSF) leak.1 The authors concluded that the application of intrathecal gadolinium in MR myelography, as described by Zeng et al,2 although it is still an off-label use, may be a valuable alternative to radioisotope cisternography or computed tomographic myelography for the detection of spinal CSF leaks, avoiding ionizing radiation.1
Background and purpose:
CT myelography has historically been the test of choice for localization of CSF fistula in patients with spontaneous intracranial hypotension. This study evaluates the additional benefits of intrathecal gadolinium MR myelography in the detection of CSF leak.
Materials and methods:
We performed a retrospective review of patients with spontaneous intracranial hypotension who underwent CT myelography followed by intrathecal gadolinium MR myelography. All patients received intrathecal iodine and off-label gadolinium-based contrast followed by immediate CT myelography and subsequent intrathecal gadolinium MR myelography with multiplanar T1 fat-suppressed sequences. CT myelography and intrathecal gadolinium MR myelography images were reviewed by an experienced neuroradiologist to determine the presence of CSF leak. Patient records were reviewed for demographic data and adverse events following the procedure.
Results:
Twenty-four patients met both imaging and clinical criteria for spontaneous intracranial hypotension and underwent CT myelography followed by intrathecal gadolinium MR myelography. In 3/24 patients (13%), a CSF leak was demonstrated on both CT myelography and intrathecal gadolinium MR myelography, and in 9/24 patients (38%), a CSF leak was seen on intrathecal gadolinium MR myelography (P = .011). Four of 6 leaks identified independently by intrathecal gadolinium MR myelography related to meningeal diverticula. CT myelography did not identify any leaks independently. There were no reported adverse events.
Conclusions:
Present data demonstrate a higher rate of leak detection with intrathecal gadolinium MR myelography when investigating CSF leaks in our cohort of patients with spontaneous intracranial hypotension. Although intrathecal gadolinium is an FDA off-label use, all patients tolerated the medication without evidence of complications. Our data suggest that intrathecal gadolinium MR myelography is a well-tolerated examination with significant benefit in the evaluation of CSF leak, particularly for patients with leak related to meningeal diverticula.
Post-dural puncture headache (PDPH) due to excessive cerebrospinal fluid (CSF) leakage is a well-known complication of lumbar puncture. Although various factors, especially the type of spinal needle, have been demonstrated to be associated with PDPH, the clinical implications of CSF leakage detected on magnetic resonance myelography (MRM) images remain unclear. The objective of this case--control study was to evaluate the association between radiologically visualized CSF leakage and PDPH.
Clinical data including patients' age and gender, types of spinal needle, duration of bed rest, interval between lumbar puncture procedures and MRM studies, and incidence of PDPH were compared between patients who were radiologically-positive and -negative for CSF leakage.
Of the 22 patients with definite CSF leakage on MRM images, most were asymptomatic (86%, 19/22). The remaining three patients, who were suffering from PDPH, only complained of headaches and were treated conservatively. In a review of patients' clinical data, there were no significant differences in any parameter including the incidence of PDPH between the 22 patients who were radiologically-positive for CSF leakage and the 31 radiologically-negative patients.
The significance of radiologically visualized CSF leakage should not be overestimated, as most such incidents are not associated with PDPH and do not require any treatment.
Objective: Funnel plots (plots of effect estimates against sample size) may be useful to detect bias in meta-analyses that were later contradicted by large trials. We examined whether a simple test of asymmetry of funnel plots predicts discordance of results when meta-analyses are compared to large trials, and we assessed the prevalence of bias in published meta-analyses. Design: Medline search to identify pairs consisting of a meta-analysis and a single large trial (concordance of results was assumed if effects were in the same direction and the meta-analytic estimate was within 30
In 2003, the QUADAS tool for systematic reviews of diagnostic accuracy studies was developed. Experience, anecdotal reports, and feedback suggested areas for improvement; therefore, QUADAS-2 was developed. This tool comprises 4 domains: patient selection, index test, reference standard, and flow and timing. Each domain is assessed in terms of risk of bias, and the first 3 domains are also assessed in terms of concerns regarding applicability. Signalling questions are included to help judge risk of bias. The QUADAS-2 tool is applied in 4 phases: summarize the review question, tailor the tool and produce review-specific guidance, construct a flow diagram for the primary study, and judge bias and applicability. This tool will allow for more transparent rating of bias and applicability of primary diagnostic accuracy studies.
CSF-venous fistulas (CVFs), first described in 2014, represent an important cause of spontaneous intracranial hypotension (SIH). CVFs can be challenging to detect on conventional anatomic imaging because, unlike other types of spinal CSF leak, they do not typically result in pooling of fluid in the epidural space, and imaging signs of CVF may be subtle. Specialized myelographic techniques have been developed to help with CVF identification, but these techniques are not yet widely disseminated. This article reviews the current understanding of CVFs, emphasizing correlations between venous anatomy and imaging findings as well as potential mechanisms for pathogenesis, and describes current imaging techniques used for CVF diagnosis and localization. These techniques are broadly classified into fluoroscopy-based methods, including digital subtraction myelography and dynamic myelography, as well as cross-sectional methods, including decubitus CT myelography and MR myelography with intrathecal gadolinium. Knowledge of these various options, including their relative advantages and disadvantages, is critical in the care of patients with SIH. Investigation is ongoing, and continued advances are anticipated in understanding of CVFs as well as in optimal imaging detection.
Objective: To investigate the characteristics of magnetic resonance myelography (MRM) and its application in the treatment of spontaneous intracranial hypotension (SIH). Methods: The clinical data, MRM characteristics, and treatment of 15 patients with SIH who underwent MRM examination in the First Affiliated Hospital of Zhengzhou University from August 2014 to August 2019 were retrospectively analyzed. According to treatment methods, nine patients were divided into conservative treatment group and six patients were divided into combined epidural blood patch treatment group. The gender, age, time interval from onset to MRM examination, cerebrospinal fluid pressure and MRM characteristics between the two groups were compared. SPSS 20.0 software was used for statistical description, and independent sample t-test was applied to compare the differences between groups. Results: All of the 15 cases reported orthostatic headache. Their cerebrospinal fluid pressure was (29.67±19.77, range 0-55) mmH2O (1 mmH2O=0.009 8 kPa), and onset-MRM interval was (33.07±24.22, range 7-90) days. The MRM characteristics were observed, including all 15 cases with periradicular leaks, four cases with anterior epidural fluid collections, six cases with posterior epidural fluid collections, and eight cases with high cervical (C1-2 to C2-3) retrospinal cerebrospinal fluid collections. There were 2 to 32 leak sites with an average of (10.20±7.87) sites. Among the 153 leak sites, 58(37.9%) sites were located at cervical vertebra, 77(50.3%) sites at thoracic vertebra, 18(11.8%) sites at lumbar vertebra, and 61(39.9%) sites at either the cervicothoracic junction (C7-T1 to T1-2) or the upper thoracic region (T2-3 to T6-7). Five patients responded well to one-time targeted autologous epidural blood patch on the basis of the location of the cerebrospinal fluid leakage. Besides, one patient improved with targeted epidural blood patch twice. There were no statistically significant differences in gender, age, onset-MRM interval, cerebrospinal fluid pressure, number and location of leak sites between the conservative treatment group and combined treatment group. Conclusions: The periradicular leaks of cerebrospinal fluid at cervical vertebra and thoracic vertebra are the most common feature of MRM in patients with SIH. MRM can identify the existence and location of cerebrospinal fluid leakage, assist in the diagnosis of SIH, and guide targeted epidural blood patch.
Objective
Assess the diagnostic yield of lateral decubitus digital subtraction myelography (LDDSM) and stratify LDDSM diagnostic yield by the Bern spontaneous intracranial hypotension (SIH) score of the pre-procedure brain MRI.
Methods
This retrospective diagnostic study included consecutive adult patients investigated for SIH who underwent LDDSM. Patients without pre-procedure brain and spine MRI, and patients with extradural fluid collection on spine MRI (type 1 leak) were excluded. LDDSM images and brain MRIs were assessed by two independent blinded readers; a third reader adjudicated any discrepancies. Diagnostic yield of LDDSM was assessed, both overall and stratified by Bern SIH scoring.
Results
Of the 62 patients included in this study, 33(53.2%) had a CSF leak identified on LDDSM. Right-sided leaks were more common (70.6%), and the most commonly identified levels of leaks were at T6, T7, and T10. No leak was found in any of the 9 patients with Bern SIH score of 2 or less. Of the 11 patients with Bern SIH score of 3-4, 5(45.5%) had a CSF leak identified, while of the 42 patients with Bern SIH score of 5 or higher, 28(66.7%) had a CSF leak identified.
Conclusions
LDDSM has a high diagnostic yield for finding the exact location of spinal CSF leak, and the diagnostic yield increases with higher Bern SIH score. No leaks were found in patients with Bern SIH score of 2 or less, suggesting that foregoing invasive testing such as LDDSM in these patients may be appropriate unless accompanied by high clinical suspicion.
Classification of Evidence
This study provides Class II evidence that for patients with suspected SIH, higher Bern SIH scores are associated with a greater likelihood of LDDSM-identified CSF leaks.
Background Existing guidelines are inconsistent regarding the indications for staging brain MRI in patients with newly diagnosed, early-stage non-small cell lung cancer (NSCLC). Purpose To evaluate the diagnostic yield of staging brain MRI in the initial evaluation of lung cancer. Materials and Methods This retrospective, observational, single-institution study included patients with newly diagnosed NSCLC who underwent staging chest CT and staging brain MRI from November 2017 to October 2018. Diagnostic yield was defined as the proportion of patients with brain metastases among all patients. Yield was stratified into clinical stage groups per the eighth edition of the American Joint Committee on Cancer staging guidelines, based on staging chest CT and in adenocarcinoma with epidermal growth factor receptor (EGFR) gene mutation and anaplastic lymphoma kinase (ALK) gene rearrangement. Subgroup analyses were performed on the basis of cell types and molecular markers. The χ2 test was performed to compare the diagnostic yields, and Bonferroni correction was used to account for multiple testing between stage groups. Results A total of 1712 patients (mean age, 64 years ± 10 [standard deviation]; 1035 men) were included. The diagnostic yield of staging brain MRI in newly diagnosed NSCLC was 11.9% (203 of 1712; 95% confidence interval [CI]: 10.4%, 13.5%). In clinical stage IA, IB, and II disease, the diagnostic yields were 0.3% (two of 615; 95% CI: 0.0%, 1.2%), 3.8% (seven of 186; 95% CI: 1.5%, 7.6%), and 4.7% (eight of 171; 95% CI: 2.0%, 9.0%), respectively. The diagnostic yield was higher in patients with adenocarcinoma (13.6%; 176 of 1297; 95% CI: 11.8%, 15.6%) than squamous cell carcinoma (5.9%; 21 of 354; 95% CI: 3.7%, 8.9%) and in patients with EGFR mutation-positive adenocarcinoma (17.5%; 85 of 487; 95% CI: 14.2%, 21.1%) than with EGFR mutation-negative adenocarcinoma (10.6%; 68 of 639; 95% CI: 8.4%, 13.3%) (P < .001 for both). Conclusion The diagnostic yield of staging brain MRI in clinical stage IA non-small cell lung cancer was low, but staging brain MRI had a higher diagnostic yield in clinical stage IB and epidermal growth factor receptor mutation-positive adenocarcinoma. © RSNA, 2020 Online supplemental material is available for this article.
OBJECTIVE. The existing literature lacks research into the benefits of initial screening imaging for patients with cerebellar hemangioblastoma. We aimed to evaluate the diagnostic yield of initial screening imaging using abdominal CT and whole-spine MRI in patients with cerebellar hemangioblastoma. MATERIALS AND METHODS. This retrospective study included 117 consecutive patients with histopathologically confirmed, newly diagnosed cerebellar hemangioblastomas at a single tertiary hospital between January 2006 and October 2018. Patients underwent contrast-enhanced abdominal CT, whole-spine MRI, or both to detect abdominal and spinal lesions of von Hippel-Lindau disease. Diagnostic yields and false referral rates for initial screening imaging were determined. RESULTS. After exclusion of six patients who forewent any initial imaging, 111 patients were included (53 men [mean age ± SD, 51 ± 13 years] and 58 women [mean age, 43 ± 16 years]). The diagnostic yield of abdominal CT was 3.8% (4 of 105; 95% CI, 1.1-9.3%), whereas the false referral rate was 1.0% (1 of 105; 95% CI, 0.0-5.2%). For whole-spine MRI, the corresponding values were 5.6% (4 of 71; 95% CI, 1.6-13.8%) and 2.8% (2 of 71; 95% CI, 0.3-9.8%), respectively. The respective diagnostic yields in patients with a single cerebellar hemangioblastoma were both 0% (0 of 98 and 66, respectively). CONCLUSION. For patients with a single cerebellar hemangioblastoma, screening examinations with abdominal CT and whole-spine MRI are unnecessary before the results of genetic testing are available.
Background and purpose:
Spine MR imaging plays a pivotal role in the diagnostic work-up of spontaneous intracranial hypotension. The aim of this study was to compare the diagnostic accuracy of unenhanced spine MR imaging and intrathecal gadolinium-enhanced spine MR imaging for identification and localization of CSF leaks in patients with spontaneous intracranial hypotension.
Materials and methods:
A retrospective study of patients with spontaneous intracranial hypotension examined from February 2013 to October 2017 was conducted. Their spine MR imaging was reviewed by 3 blinded readers for the presence of epidural CSF using 3 different sequences (T2WI, 3D T2WI fat-saturated, T1WI gadolinium). In patients with leaks, the presumed level of the leak was reported.
Results:
In total, 103 patients with spontaneous intracranial hypotension (63/103 [61%] women; mean age, 50 years) were evaluated. Seventy had a confirmed CSF leak (57/70 [81%] proved intraoperatively), and 33 showed no epidural CSF on multimodal imaging. Intrathecal gadolinium-enhanced spine MR imaging was nonsuperior to unenhanced spine MR imaging for the detection of epidural CSF (P = .24 and .97). All MR imaging sequences had a low accuracy for leak localization. In all patients, only 1 leakage point was present, albeit multiple suspicious lesions were reported in all sequences (mean, 5.0).
Conclusions:
Intrathecal gadolinium-enhanced spine MR imaging does not improve the diagnostic accuracy for the detection of epidural CSF. Thus, it lacks a rationale to be included in the routine spontaneous intracranial hypotension work-up. Heavily T2-weighted images with fat saturation provide high accuracy for the detection of an epidural CSF collection. Low accuracy for leak localization is due to an extensive CSF collection spanning several vertebrae (false localizing sign), lack of temporal resolution, and a multiplicity of suspicious lesions, albeit only a single leakage site is present. Thus, dynamic examination is mandatory before targeted treatment is initiated.
Heavily T2-weighted MR myelography (HT2W-MRM) is emerging as an alternative approach for detection and follow up of CSF leaks. We aimed to assess epidural blood patch (EBP) treatment outcome when using HT2W-MRM as the primary modality for detecting CSF leak and planning EBP placement in routine clinical practice. Since 2018, patients at our institute suspected of having CSF leak, routinely HT2W-MRM instead of CT myelography to determine presence of the leak and identify the EBP target site. Fifty-nine consecutive patients suspected of having a CSF leak underwent HT2W-MRM. After excluding patients with subdural hematoma and poor image quality, 26 (10 men, 16 women; mean age 44.92 ± 12.6 years) patients were included in this study. Patients received EBP on the basis of HT2W-MRM assessments and clinical assessment. Imaging findings and clinical outcome were evaluated. CSF leak was identified in 21 patients (80.8%, 21/26) based HT2W-MRM. Most cases were graded on a confidence scale as CSF leak definitely (n = 13) or probably (n = 3) present. Successful clinical EBP treatment was achieved in 14 of 17 patients (82.4%) after first targeted EBP, and patient symptoms significantly improved after treatment (numerical rating score 6.4 before EBP, 1.3 after EBP, P < 0.001). HT2W-MRM based EBP are the rational and effective choices for CSF leak treatment in routine clinical practice.
Background and purpose:
Localization of the culprit CSF leak in patients with spontaneous intracranial hypotension can be difficult and is inconsistently achieved. We present a high yield systematic imaging strategy using brain and spine MRI combined with digital subtraction myelography for CSF leak localization.
Materials and methods:
During a 2-year period, patients with spontaneous intracranial hypotension at our institution underwent MR imaging to determine the presence or absence of a spinal longitudinal extradural collection. Digital subtraction myelography was then performed in patients positive for spinal longitudinal extradural CSF collection primarily in the prone position and in patients negative for spinal longitudinal extradural CSF collection in the lateral decubitus positions.
Results:
Thirty-one consecutive patients with spontaneous intracranial hypotension were included. The site of CSF leakage was definitively located in 27 (87%). Of these, 21 were positive for spinal longitudinal extradural CSF collection and categorized as having a ventral (type 1, fifteen [48%]) or lateral dural tear (type 2; four [13%]). Ten patients were negative for spinal longitudinal extradural CSF collection and were categorized as having a CSF-venous fistula (type 3, seven [23%]) or distal nerve root sleeve leak (type 4, one [3%]). The locations of leakage of 2 patients positive for spinal longitudinal extradural CSF collection remain undefined due to resolution of spontaneous intracranial hypotension before repeat digital subtraction myelography. In 2 (7%) patients negative for spinal longitudinal extradural CSF collection, the site of leakage could not be localized. Nine of 21 (43%) patients positive for spinal longitudinal extradural CSF collection were treated successfully with an epidural blood patch, and 12 required an operation. Of the 10 patients negative for spinal longitudinal extradural CSF collection (8 localized), none were effectively treated with an epidural blood patch, and all have undergone (n = 7) or are awaiting (n = 1) an operation.
Conclusions:
Patients positive for spinal longitudinal extradural CSF collection are best positioned prone for digital subtraction myelography and may warrant additional attempts at a directed epidural blood patch. Patients negative for spinal longitudinal extradural CSF collection are best evaluated in the decubitus positions to reveal a CSF-venous fistula, common in this population. Patients with CSF-venous fistula may forgo further epidural blood patch treatment and go on to surgical repair.
Objective: To investigate clinical and imaging features of 40 patients with spontaneous intracranial hypotension (SIH).
Methods: 40 cases of spontaneous intracranial hypotension (SIH) diagnosed in our hospital from June 2013 to September 2017 were collected and retrospectively analyzed.
Results: In our study, the male to female ratio was 2:3. The average age of onset was 43.0 ± 15.0 years. There were 12 (30.0%) patients with clear incentives, mostly catching cold. The average length of hospital stay was 11.2 ± 6.3 days. All the patients showed orthostatic headaches, 62.5% patients with nausea or vomiting, 40.0% patients with neck stiffness, 17.5% patients with dizziness and vertigo, 10.0% patients with numbness and weakness of limbs, 5% patients with neck discomfort, and 2.5% patients with visual symptoms (visual impairment, photophobia, diplopia). 24 patients underwent CT scans which showed no abnormalities in 20 cases (83.3%), subdural fluid accumulation in 3 cases (12.5%), and subdural haematoma in 1 case (2.5%). Cranial contrast-enhanced MR scans showed diffuse pachymeningeal enhancement (95.83%, 23/24), signs of pituitary hyperaemia in 5 cases (20.8%), subdural fluid accumulation and subdural hematoma in 4 cases (16.7%), sagging of the brain in 3 cases (12.5%), and engorgement of venous structures in 1 case (4.1%). Six patients underwent plain and contrast-enhanced spinal MR scans which showed varying degrees of dural thickening and enhanced performance in all the patients. 92.5% (37/40) of patients had cerebrospinal fluid pressure <60 mmH2O on lumbar puncture. 97.5% of patients underwent conservative treatment with drugs and had a good outcome.
Conclusion: Orthostatic headache and cranial MRI diffuse pachymeningeal enhancement are characteristic features of SIH. Cranial contrast-enhanced MR scan is recognized as the first and non-invasive investigation in the diagnosis of SIH. Most patients had cerebrospinal fluid pressure <60 mmH2O. The vast majority of patients improved with fluid replacement.
Objectives:
Several brain and spinal magnetic resonance imaging signs have been described in spontaneous intracranial hypotension. Their correlations are not fully studied. This study aimed to explore potential mechanisms underlying cerebral neuroimaging findings and to examine associations among spinal and brain magnetic resonance imaging signs.
Methods:
We conducted a retrospective review of magnetic resonance myelography and brain magnetic resonance imaging records of patients with spontaneous intracranial hypotension. Categorical principal component analysis was employed to cluster brain neuroimaging findings. Spearman correlation was employed to analyze associations among different brain neuroimaging findings and between brain and spinal neuroimaging findings.
Results:
In patients with spontaneous intracranial hypotension (n = 148), categorical principal component analysis of brain neuroimaging signs revealed two clusters: Cerebral venous dilation and brain descent. Among all brain magnetic resonance imaging signs examined, only midbrain-pons angle associated with anterior epidural cerebrospinal fluid collection length (surrogate spinal cerebrospinal fluid leak severity) (n = 148, Spearman's ρ = -0.38, p < .001). Subgroup analyses showed that the association between midbrain-pons angle (within brain descent cluster) and spinal cerebrospinal fluid leak severity was presented in patients with convex margins of the transverse sinuses (n = 122, Spearman's ρ = -0.43, p < .001), but not in patients without convex margins (n = 26, Spearman's ρ = -0.19, p = .348). The association between severity of transverse sinus distension and spinal cerebrospinal fluid leak severity was only presented in patients without convex margins (n = 26, Spearman's ρ = 0.52, p = .006).
Conclusion:
This study indicates that there are two factors behind the brain neuroimaging findings in spontaneous intracranial hypotension: Cerebral venous dilation and brain descent. Certain brain neuroimaging signs correlate with spinal cerebrospinal fluid leakage severity, depending on different circumstances.
Objective An epidural blood patch (EBP) is the mainstay of treatment for refractory spontaneous intracranial hypotension (SIH). We evaluated the treatment efficacy of targeted EBP in refractory SIH.
Methods All patients underwent brain magnetic resonance imaging (MRI) with contrast and heavily T2-weighted spine MRI. Whole spine computed tomography (CT) myelography with non-ionic contrast was performed in 46 patients, and whole spine MR myelography with intrathecal gadolinium was performed in 119 patients. Targeted EBPs were placed in the prone position one or two vertebral levels below the cerebrospinal fluid (CSF) leaks. Repeat EBPs were offered at 1-week intervals to patients with persistent symptoms, continued CSF leakage, or with multiple leakage sites.
Results Brain MRIs showed pachymeningeal enhancement in 127 patients and subdural hematomas in 32 patients. One hundred fifty-two patients had CSF leakages on heavily T2-weighted spine MRIs. CSF leaks were also detected on CT and MR myelography in 43 and 111 patients, respectively. Good recovery was achieved in all patients after targeted EBP. No serious complications occurred in patients treated with targeted EBP during the 1 to 7 years of follow-up.
Conclusions Targeted and repeat EBPs are rational choices for treatment of refractory SIH caused by CSF leakage.
In the field of interventional pain medicine a radiocontrast agent is commonly used in conjunction with fluoroscopy. Limited work has been published regarding the use of gadolium based contrast agents (GBCA) in the intrathecal space. We report a case of an intrathecal gadobutrol injection resulting in neurotoxic manifestations.A 60-year-old female with a history significant for lumbar post-laminectomy syndrome and intrathecal drug delivery implantation was admitted for lumbar fusion and kyphoplasty. Postoperatively, the patient had escalating pain medication requirements. A pump and intrathecal catheter contrast study was completed to assess the integrity and proper placement of the intrathecal catheter. Due to patient.s allergy to iodinated contrast, the physician requested gadolinium contrast dye. Unknown to the staff was that Magnevist had recently been replaced with an alternative GBCA, Gadavist (gadobutrol). 2 cc of Gadavist was injected. The catheter was determined to be intact and in proper position. Less than five minutes after the injection of gadobutrol, the patient reported spastic pain of the lower extremities. There is a lack of evidence as it relates to the use of GBCA specifically gadobutrol in the intrathecal space. The use of gadobutrol in the intrathecal space should be used with caution.
Objective:
To evaluate the imaging characteristics and diagnostic utility of the "Dinosaur tail sign" in the diagnosis of cerebrospinal fluid (CSF) leakage.
Background:
The authors propose the "Dinosaur tail sign," defined as a combination of the dorsal epidural hyperintensities, fat tissue, spinal cord, and cauda equine on lumbosacral sagittal fat-suppressed T2-weighted image (FST2WI), as a sensitive indicator for diagnosing CSF leakage.
Methods:
Imaging characteristics of the "Dinosaur tail sign" was evaluated in seven spontaneous intracranial hypotension (SIH) and 23 iatrogenic CSF leakage (ICSFL) patients. Additionally, the diagnostic index was compared between the "Dinosaur tail sign" and other previously reported useful magnetic resonance imaging (MRI) and magnetic resonance myelography (MRM) findings.
Results:
In contrast to other imaging findings including the epidural expansion, floating dural sac sign, and distension of the spinal epidural veins on MRI, and paraspinal fluid collections (PFC) on MRM, the "Dinosaur tail sign" was found equally in both SIH and ICSFL patients (6 SIH and 19 ICSFL; 83% of all patients with CSF leakage). The "Dinosaur tail sign" showed sufficient diagnostic utility (sensitivity 83%, specificity 94%, accuracy 89%) that was comparable to that of PFC.
Conclusion:
The "Dinosaur tail sign" is a useful imaging finding suggestive of CSF leakage. Evaluation of subtle interspinous arched hyperintensities on spinal MRI is mandatory for the diagnosis of SIH and ICSFL.
Background and purpose:
CSF hypovolemia is a core feature of spontaneous intracranial hypotension. Spontaneous intracranial hypotension is characterized by orthostatic headache and radiologic manifestations, including CSF along the neural sleeves, diffuse pachymeningeal enhancement, and/or venous engorgement. However, these characteristics are only qualitative. Quantifying intraspinal CSF volumes could improve spontaneous intracranial hypotension diagnosis and evaluation of hypovolemic statuses in patients with spontaneous intracranial hypotension. The purpose of this study was to compare intraspinal CSF volumes across spontaneous intracranial hypotension stages and to test the clinical applicability of these measures.
Materials and methods:
A cohort of 23 patients with spontaneous intracranial hypotension and 32 healthy controls was subjected to brain MR imaging and MR myelography with 1.5T imaging. An automatic threshold-based segmentation method was used to calculate intraspinal CSF volumes at initial hospitalization (spontaneous intracranial hypotension-initial), partial improvement (spontaneous intracranial hypotension-intermediate), and complete recovery (spontaneous intracranial hypotension-recovery) stages.
Results:
The mean intraspinal CSF volumes observed were the following: 95.31 mL for healthy controls, 72.31 mL for spontaneous intracranial hypotension-initial, 81.15 mL for spontaneous intracranial hypotension-intermediate, and 93.74 mL for spontaneous intracranial hypotension-recovery. Increased intraspinal CSF volumes were related to disease recovery (P < .001). The intraspinal CSF volumes of patients before complete recovery were significantly lower than those of healthy controls. With the estimated intradural CSF volumes as a reference, the intraspinal CSF volume percentage was lower in patients with spontaneous intracranial hypotension with venous engorgement than in those without it (P = .058).
Conclusions:
With a threshold-based segmentation method, we found that spinal CSF hypovolemia is fundamentally related to spontaneous intracranial hypotension. Intraspinal CSF volumes could be a sensitive parameter for the evaluation of treatment response and follow-up monitoring in patients with spontaneous intracranial hypotension.
Objective:
Spinal leakage of CSF causes almost all cases of spontaneous intracranial hypotension. Leak detection and localization are important for both diagnosis and treatment. The myelographic appearance of the leaks may vary, however, depending on the cause of the leak, rate of leakage, and imaging modality used.
Conclusion:
The purpose of this article is to review the imaging of spinal CSF leaks and to assist in the selection of appropriate imaging modalities in this condition.
Characterizing the normal distribution of cerebrospinal fluid (CSF) in the spine is crucial for an accurate assessment of CSF leakage and other abnormalities. Magnetic resonance myelography (MRM) is a noninvasive diagnostic method that is commonly used to evaluate the spinal distribution of CSF. Our aim was to evaluate the anatomical distribution of CSF in the spine of healthy individuals, by MRM using the three-dimensional sampling perfection with amplification-optimized contrasts using flip-angle evolutions (3D-SPACE) sequence. Twenty-one healthy volunteers underwent whole-spine MRM imaging using the 3D-SPACE sequence. MRM images were reconstructed with 5-mm axial multiplanar reconstruction (MPR) and maximum intensity projection (MIP) at each spine level. Two radiologists evaluated CSF distribution from the spinal canal in the MPR and MIP images, using 7-point (types A-G) and 3-point (grades 0-3) classification systems, respectively. Inter-reader agreement was calculated with the kappa coefficient (κ). Reader 1/reader 2 evaluated 46/53, 67/57, 4/6, 0/0, 0/0, 7/5, and 2/5 cervical spine (C-spine)-level MPR images corresponding to types A-G, respectively (κ = 0.74). Numbers at the thoracic spine (T-spine) level were 185/186, 41/44, 8/5, 0/0, 0/0, 16/11, and 2/6, respectively (κ = 0.69), and at the lumbar spine (L-spine) level were 46/58, 25/23, 9/5, 0/0, 0/0, 19/13, and 6/6, respectively (κ = 0.50). Inter-reader agreement for MPR images at the whole-spine level was considered good (κ = 0.69). Reader 1/reader 2 evaluated 0/0, 13/13, 8/8, and 0/0 MIP images at the C-spine level corresponding to grades 0-3, respectively (κ = 0.80). Numbers at the T-spine level were 10/14, 8/5, 3/2, and 0/0, respectively (κ = 0.67), and at the L-spine level were 5/2, 10/8, 6/11, and 0/0, respectively (κ = 0.26). Inter-reader agreement for MIP images at the whole-spine level was considered good (κ = 0.61). In conclusion, T2-weighted MRM with 3D-SPACE sequence imaging can be a useful technique to detect the normal distribution of CSF in the spinal canal. Understanding the normal distribution of CSF in the spinal canal is necessary to achieve an accurate diagnosis of CSF leakage.
Objective: To compare the diagnostic value between spinal MR myelography (MRM) and intrathecal Gadolinium MR myelography (GdM) in detecting spinal cerebrospinal fluid (CSF) leaks of spontaneous intracranial hypotension (SIH). Methods: Retrospective analysis of imaging findings in 158 cases with SIH was performed. Both MRM and GdM were available in 24 cases, and MRM was performed first, followed by GdM within one week. Morphological abnormalities of nerve root, CSF leaks along the nerve roots, and abnormal CSF collections were observed and compared between the two methods by using McNemar statistics and Kappa test statistics. Results: Morphological abnormalities of nerve root were detected in 176 lesions on GdM and 163 lesions on MRM, respectively, and GdM was more sensitive in the detection of morphological abnormalities of nerve root (χ2=6.26, P=0.011). CSF leaks along nerve roots were identified in 15 patients on both GdM and MRM while in 5 cases on neither GdM nor MRM, and identified in 4 patients on GdM but not on MRM. CSF leaks along the nerve roots were detected in 67 lesions on GdM and 55 lesions on MRM, respectively, and GdM was more sensitive in the detection of CSF leaks along nerve (χ2=6.05, P=0.012). MRM and GdM showed good consistency (Kappa =0.837, P=0.001) in detecting CSF leaks for patients with SIH. Six and 14 lesions of abnormal CSF collections in bony rims of spines were respectively detected by GdM and MRM, 12 and 28 lesions of abnormal CSF collections in bony rims of the ribs were respectively detected by GdM and MRM. MRM was more sensitive in the detection of abnormal CSF collections in bony rims of the spines and the ribs (χ2=6.13, 14.06, P=0.008, 0.001). Eleven and 10 lesions of CSF collections in epidural space were respectively detected by GdM and MRM, 1 and 3 lesions of CSF collections of C1-2 retrospinal space were respectively detected by GdM and MRM. No statistically significant differences existed between MRM and GdM in detecting CSF collections of epidural space and C1-2 retrospinal space (χ2=0.01, 0.50, P= 1.000, 0.500). Conclusions: MRM and GdM have their respective advantages in detecting spinal CSF leaks along the nerve roots, morphological abnormalities of nerve root and abnormal CSF collections. MRM combined with GdM can provide more information in localizing spinal CSF leaks for patients with SIH.
OBJECT
A CSF leak can be difficult to locate in patients who present with spontaneous intracranial hypotension (SIH). The purpose of this case series was to describe the authors’ experience with intrathecal preservative-free normal saline challenge coupled with contrast-enhanced MR myelography (CEMRM), which was used to provoke and detect a CSF leakage site in patients with SIH.
METHODS
The authors performed a retrospective review of the records of patients who underwent preservative-free normal saline challenge followed by intrathecal gadolinium (Gd) contrast infusion and MR myelography from 2010 to 2012.
RESULTS
The records survey identified 5 patients who underwent 6 procedures. Intrathecal preservative-free normal saline challenge followed by CEMRM identified a CSF leak during 5 of the 6 procedures. Previous CT myelograms were available from 4 patients, which did not reveal a leakage site. A CT myelogram of 1 patient showed a single leak, but the authors’ saline challenge-CEMRM technique identified multiple additional leakage sites. Three patients exhibited transient postprocedural symptoms related to the saline infusion, but no long-term or permanent adverse effects related to the procedure were observed.
CONCLUSIONS
Instillation of preservative-free normal saline into the thecal sac followed by intrathecal Gd infusion is a safe technique that may increase the detection of a CSF leak on MR myelography images in patients with SIH.
Full text of letter at: http://www.bmj.com/content/316/7129/469
Although the concept is useful, the method proposed by Egger et al to detect bias in meta-analyses is itself biased1: it overestimates the occurrence and extent of publication bias. This is easily shown by simulating data for a meta-analysis of a hypothetical intervention that is effective (and therefore has a negative regression coefficient by Egger et al's method) and is free of publication bias (and hence should have an intercept of zero in the regression analysis).
In our simulations, each study was of a treated group and a control group, both of equal size. For each simulated meta-analysis, studies ranging from 100 per group to 1000 per group, in increments of 100, were generated. The observed number of events in each group was generated from a binomial distribution.
Here is one example in which the true event rate is 40% in the control group and 10% in the treatment group. When the true population values (which would not be known in practice) are used to estimate precision, the regression coefficient is −1.7942 (an estimated log odds ratio equivalent to the expected value of 0.1667) and the intercept (0.0380, P=0.1) is close to the expected value of zero, reflecting the lack of publication bias. However, the regression coefficient estimated when the precision is based on the observed values, as would occur using Egger et al's method, is −1.7169. More importantly, the intercept is −0.4492 and significant (P<0.0001), incorrectly suggesting that there has been publication bias. In general, our other simulations suggest that the bias in the estimated intercept is greater the more effective the intervention actually is and the smaller the sample size of the studies.
This problem has several causes. Firstly, the estimates of precision are subject to random error due to sampling variability. This regression-dilution bias causes the regression slope to “tilt” around the mean of the predictor and response variables so that its coefficient is closer to zero; this in turn leads to the intercept becoming negative.2 Secondly, the estimated standardised log odds ratio is correlated with the estimated precision. Thirdly, the precision estimated by the method that we assume Egger et al used3 is a biased estimate of the true precision, with the degree of bias increasing as sample size decreases.4
Clearly, until the causes of the problems we have outlined are better elucidated and solutions developed, one cannot rely on the method proposed by Egger et al to detect publication bias.
In 2003, the QUADAS tool for systematic reviews of diagnostic accuracy studies was developed. Experience, anecdotal reports, and feedback suggested areas for improvement; therefore, QUADAS-2 was developed. This tool comprises 4 domains: patient selection, index test, reference standard, and flow and timing. Each domain is assessed in terms of risk of bias, and the first 3 domains are also assessed in terms of concerns regarding applicability. Signalling questions are included to help judge risk of bias.
The QUADAS-2 tool is applied in 4 phases: summarize the review question, tailor the tool and produce review-specific guidance, construct a flow diagram for the primary study, and judge bias and applicability. This tool will allow for more transparent rating of bias and applicability of primary diagnostic accuracy studies.
The spatial distribution and clinical correlation of cerebrospinal fluid leakage after lumbar puncture have not been determined. Adult in-patients receiving diagnostic lumbar punctures were recruited prospectively. Whole-spine heavily T2-weighted magnetic resonance myelography was carried out to characterize post-lumbar puncture spinal cerebrospinal fluid leakages. Maximum rostral migration was defined as the distance between the most rostral spinal segment with cerebrospinal fluid leakage and the level of lumbar puncture. Eighty patients (51 female/29 male, mean age 49.4 ± 13.3 years) completed the study, including 23 (28.8%) with post-dural puncture headache. Overall, 63.6% of periradicular leaks and 46.9% of epidural collections were within three vertebral segments of the level of lumbar puncture (T12-S1). Post-dural puncture headache was associated with more extensive and more rostral distributions of periradicular leaks (length 3.0 ± 2.5 versus 0.9 ± 1.9 segments, P = 0.001; maximum rostral migration 4.3 ± 4.7 versus 0.8 ± 1.7 segments, P = 0.002) and epidural collections (length 5.3 ± 6.1 versus 1.0 ± 2.1 segments, P = 0.003; maximum rostral migration 4.7 ± 6.7 versus 0.9 ± 2.4 segments, P = 0.015). In conclusion, post-dural puncture headache was associated with more extensive and more rostral distributions of periradicular leaks and epidural collections. Further, visualization of periradicular leaks was not restricted to the level of dural defect, although two-thirds remained within the neighbouring segments.
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Object:
Precise localization and understanding of the origin of spontaneous high-flow spinal CSF leaks is required prior to targeted treatment. This study demonstrates the utility of ultrafast dynamic CT myelography for the precise localization of high-flow CSF leaks caused by spiculated spinal osteophytes.
Methods:
This study reports a series of 14 patients with high-flow CSF leaks caused by spiculated spinal osteophytes who underwent ultrafast dynamic CT myelography between March 2009 and December 2010. There were 10 male and 4 female patients, with an average age of 49 years (range 37-74 years). The value of ultrafast dynamic CT myelography in depicting the CSF leak site was qualitatively assessed.
Results:
In all 14 patients, ultrafast dynamic CT myelography was technically successful at precisely demonstrating the site of the CSF leak, the causative spiculated osteophyte piercing the dura, and the relationship of the implicated osteophyte to adjacent structures. Leak sites included 3 cervical, 11 thoracic, and 0 lumbar levels, with 86% of the leaks occurring from C-5 to T-7. Information obtained from the ultrafast dynamic CT myelogram was considered useful in all treated CSF leaks.
Conclusions:
Spinal osteophytes piercing the dura are a more frequent cause of high-flow CSF leaks than previously recognized. Ultrafast dynamic CT myelography adds value beyond standard dynamic myelography or digital subtraction myelography in the diagnosis and anatomical characterization of high-flow spinal CSF leaks caused by these osteophytes. This information allows for appropriate planning for percutaneous or surgical treatment.
A broadening of the clinical and imaging features of the spontaneous cerebrospinal fluid (CSF) leaks is now well recognized, far beyond what was thought only two decades ago. This has resulted in increasing number of patients with atypical and unusual features who, not unexpectedly, are directed to headache specialists and tertiary referral centers. In many cases, obviously the fundamental question of presence or absence of CSF leak will need to be addressed prior to proceeding with further and often more involved, more invasive, and more costly diagnostic and therapeutic considerations. Radioisotope cisternography often proves to be very helpful in these situations by demonstrating reliable, although indirect, evidences of CSF leak while it is less helpful in directly identifying the exact site of the CSF leakage. In this overview article, the expectations from and the limitations of this diagnostic method are described along with some personal observations in the past 25 years.
To investigate the sensitivity of MRI of the spine compared with CT myelography (CTM) in detecting CSF leaks.
Between July 1998 and October 2010, 12 patients with orthostatic headache and a CTM-confirmed spinal CSF leak underwent an MRI of the spine with and without contrast. Using CTM as the gold standard, we retrospectively investigated the sensitivity of spinal MRI in detecting a CSF leak.
Eleven of 12 patients with a CSF leak documented by CTM also had extradural fluid collections on spinal MRI (sensitivity 91.7%). Six patients with extradural fluid collections on spinal MRI also had spinal dural enhancement.
When compared with the gold standard of CTM, MRI of the spine appears to be a sensitive and less invasive imaging modality for detecting a spinal CSF leak, suggesting that MRI of the spine should be the imaging modality of first choice for the detection of spinal CSF leaks.
Spontaneous intracranial hypotension typically results from spontaneous cerebrospinal fluid (CSF) leak, often at spine level and only rarely from skull base. Once considered rare, it is now diagnosed far more commonly than before and is recognized as an important cause of headaches. CSF leak leads to loss of CSF volume. Considering that the skull is a rigid noncollapsible container, loss of CSF volume is typically compensated by subdural fluid collections and by increase in intracranial venous blood which, in turn, causes pachymeningeal thickening, enlarged pituitary, and engorgement of cerebral venous sinuses on magnetic resonance imaging (MRI). Another consequence of CSF hypovolemia is sinking of the brain, with descent of the cerebellar tonsils and brainstem as well as crowding of the posterior fossa noted on head MRI. The clinical consequences of these changes include headaches that are often but not always orthostatic, nausea, occasional emesis, neck and interscapular pain, cochleovestibular manifestations, cranial nerve palsies, and several other manifestations attributed to pressure upon or stretching of the cranial nerves or brain or brainstem structures. CSF lymphocytic pleocytosis or increase in CSF protein concentration is not uncommon. CSF opening pressure is often low but can be within normal limits. Stigmata of disorders of connective tissue matrix are seen in some of the patients. An epidural blood patch, once or more, targeted or distant, at one site or bilevel, has emerged as the treatment of choice for those who have failed the conservative measures. Epidural injection of fibrin glue of both blood and fibrin glue can be considered in selected cases. Surgery to stop the leak is considered when the exact site of the leak has been determined by neurodiagnostic studies and when less invasive measures have failed. Subdural hematomas sometimes complicate the CSF leaks; a rebound intracranial hypertension after successful treatment of a leak is not rare. Cerebral venous sinus thrombosis as a complication is fortunately less common, and superficial siderosis and bibrachial amyotrophy are rare. Short-term recurrences are not uncommon, and long-term recurrences are not rare.
A literature search found no clinical trials or guidelines addressing the management of spontaneous intracranial hypotension (SIH). Based on the available literature and expert opinion, we have developed recommendations for the diagnosis and management of SIH. For typical cases, we recommend brain magnetic resonance (MR) imaging with gadolinium to confirm the diagnosis, and conservative measures for up to two weeks. If the patient remains symptomatic, up to three non-directed lumbar epidural blood patches (EBPs) should be considered. If these are unsuccessful, non-invasive MR myelography, radionuclide cisternography, MR myelography with intrathecal gadolinium, or computed tomography with myelography should be used to localize the leak. If the leak is localized, directed EPBs should be considered, followed by fibrin sealant or neurosurgery if necessary. Clinically atypical cases with normal brain MR imaging should be investigated to localize the leak. Directed EBPs can be used if the leak is localized; non-directed EBPs should be used only if there are indirect signs of SIH.
Introduction:
This study aimed to evaluate the diagnostic imaging findings and treatment results of patients with idiopathic intracranial hypotension (IIH) due to cerebrospinal fluid (CSF) leaks.
Methods:
Between February 2009 and April 2012, 26 IIH patients (15 men, median age 49 years) presenting with orthostatic headache (n = 20) and/or with spontaneous subdural effusions or subarachnoid hemorrhage (n = 19) were enrolled. Twenty-three patients underwent a whole spine CT and MRI myelography, starting 45 min after the intrathecal injection of 9 cc of iomeprol (Imeron 300 M) and 1 cc of gadobutrolum (Gadovist). Three patients only underwent MR myelography after intrathecal gadobutrolum injection. Adjacent to the level(s) of the detected CSF leak(s) along the nerve roots, 20 cc of fresh venous blood with 0.5 cc Gadovist was injected epidurally (blood patch, BP). The distribution of the BP was visualized by MRI the following day. Treatment results were evaluated clinically and by myelography 2 weeks after the application of the BP. Retreatment was offered to patients with persistent symptoms and continued CSF leakage.
Results:
CSF leaks were detected at the cervical (n = 12), thoracic (n = 25), or lumbar (n = 21) spine. In 23 patients, more than one spinal segment was affected. One patient refused treatment. BP were applied in one (n = 9) or several (n = 16) levels. Clinical and/or radiological improvement was achieved after one (n = 16), two (n = 5), three (n = 3), or five (n = 1) BPs.
Conclusion:
CT and MRI myelography allow the reliable detection of spinal CSF leaks. The targeted and eventually repeated epidural BP procedure is a safe and efficacious treatment.
Localization of spinal CSF leaks in CSF hypovolemia is critical in directing focal therapy. In this retrospective review, our aim was to determine whether GdM was helpful in confirming and localizing spinal CSF leaks in patients in whom no leak was identified on a prior CTM.
Forty-one symptomatic patients with clinical suspicion of SIH were referred for GdM after undergoing at least 1 CTM between February 2002 and August 2010. A retrospective review of the imaging and electronic medical records was performed on each patient.
In 17 of the 41 patients (41%), GdM was performed for follow-up of a previously documented leak at CTM. In the remaining 24 patients (59%), in whom GdM was performed for a suspected CSF leak, which was not identified on CTM, GdM localized the CSF leak in 5 of 24 patients (21%). In 1 of these 5 patients, GdM detected the site of leak despite negative findings on brain MR imaging, spine MR imaging, and CTM of the entire spine. Sixteen of 17 patients with previously identified leaks underwent interval treatment, and leaks were again identified in 12 of 17 (71%).
GdM is a useful technique in the highly select group of patients who have debilitating symptoms of SIH, a high clinical index of suspicion of spinal CSF leak, and no demonstrated leak on conventional CTM. Intrathecal injection of gadolinium contrast remains an off-label use and should be reserved for those patients who fail conventional CTM.
We sought to evaluate radioisotope cisternography (RICG)-related postpuncture CSF leakage by MRI.
We conducted a prospective 3-day imaging study. Ten patients with orthostatic headache and other symptoms underwent pre-RICG brain and spinal MRI, magnetic resonance myelography (MRM), RICG, and post-RICG spinal MRI and MRM. For RICG, we used a 25-gauge pencil point spinal needle at the L3/4 or L4/5 level after which subjects took bed rest for 2.5 hours.
On pre-RICG MRI and MRM, none of the 10 patients showed CSF leakage. However, 5 subjects (50%) showed epidural abnormalities suggesting CSF leakage on MRI after lumbar puncture for RICG. On RICG and subsequent MRM, 4 of the subjects showed definite findings of CSF leakage and 1 showed minimal leakage.
RICG carries a risk of iatrogenic CSF leakage even with careful puncturing using a fine needle. This leakage produces abnormal RICG and MRM findings at the lumbosacral level. Therefore, abnormal RICG findings restricted to the lumbosacral level should be carefully interpreted when diagnosing SIH.