Article

Clinical utility and cost-effectiveness of CT-angiography in the diagnosis of nontraumatic subarachnoid hemorrhage

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Abstract

Introduction CT-angiography gains an increasing role in the initial diagnosis of patients with nontraumatic subarachnoid hemorrhage (SAH). However, the implementation of CT-angiography does not always exclude the necessity of conventional angiography. Our objective was to determine the practical utility and cost-effectiveness of CT-angiography. Methods All patients with nontraumatic subarachnoid hemorrhage admitted to our university hospital after implementation of CT-angiography between June 1, 2011 and June 30, 2012 were retrospectively analyzed in regard to factors of treatment flow, radiation exposure, harms of contrast medium loading, and diagnostic costs. A control group of the same size was assembled from previously admitted SAH patients, who did not undergo pretreatment CT-angiography. Furthermore, cost-effectiveness analysis was performed. Results The final analysis consisted of 93 patients in each group. Of 93 patients with pretreatment CT-angiography, 74 had to undergo conventional angiography for diagnostic and/or therapeutic purposes. CT-angiography had significant impact on the reduction of collective effective radiation dose by 4.419 mSv per person (p = 0.0002) and was not associated with additional harms. Despite the significantly earlier detection of aneurysms with CT-angiography (p

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... Despite these guidelines, clinicians and researchers are divided about the necessity of using DSA to detect aneurysms after SAH. [4][5][6][7][8][9] Up to 20% of SAH patients have no aneurysm detected on initial angiography imaging. 10,11 Given that DSA is resource-intensive and invasive, CTA is increasingly being used to detect ruptured aneurysms following SAH. ...
... 24 Although DSA has long been regarded as the golden standard, an increasing number of studies show that DSA is unnecessary, invasive and costly. 8 Specifically, we propose that a DSA is unnecessary for the diagnosis of patients with SAH when a thorough CTA with appropriate protocol and review returns negative findings. On the basis of the present study, if CTA identifies no aneurysm in patients with SAH, then it can be assumed that the origin of the SAH is non-aneurysmal in nature. ...
Article
Background In patients with subarachnoid haemorrhage (SAH) and a negative finding on CT angiography (CTA), further imaging with digital subtraction angiography (DSA) is commonly performed to identify the source of bleeding. The purpose of this study was to investigate whether negative findings on CTA can reliably exclude aneurysms in patients with acute SAH. Methods This retrospective study identified all DSAs performed between August 2010 and July 2014 within our institution. CT angiography was performed with a 64-section multidetector row CT scanner. Only DSAs from patients with confirmed SAH and a negative CTA result were included in the final analyses. A fellowship-trained neuroradiologist reviewed the imaging results. Results Of the 857 DSAs, 50 (5.83%) were performed in 35 patients with CTA-negative SAH. Of the 35 patients, three (8.57%) had positive findings on the DSA. In one patient, suspicious dissection of the extra- and intra-cranial segment of the right vertebral artery could not be confirmed even in retrospect. In the second patient, the suspicious finding of tiny protuberance from the left paraclinoid internal carotid artery (ICA) on DSA did not change on follow-up and did not change patient’s management. The third patient had a posterior inferior cerebellar artery aneurysm, which was not seen on the initial CTA owing to the incomplete coverage of the head on the CTA. Conclusion In patients with SAH, negative findings on a technically sound CTA are reliable in ruling out aneurysms in any pattern of SAH or no blood on CT. Our observations need to be confirmed with larger prospective studies.
... Results of patients with aneurysmal SAH (ASAH) have been reported previously [6]. The presently applied inclusion criteria for NASAH were: 1) diagnosis of SAH verified by computed tomography (CT) scan within 72 hours after clinical onset, or, in case of negative CT scan, by lumbar puncture; 2) absence of clinical and/or radiographic signs potentially indicative of a traumatic cause of SAH; 3) exclusion of underlying vascular lesions by means of CT-angiography (CTA) and complete (four vessel) digital subtraction angiography (DSA), according to our diagnostic algorithms that were previously described [7]. The study was approved by the Institutional Review Board (Ethik-Kommission, Albert-Ludwigs-Universität Freiburg, Registration number: 446/13) and registered with the German clinical trial register (DRKS, Unique identifier: DRKS00005486). ...
... All patients were admitted to the intermediate care unit (ICU) and treated according to our SAH policy that was previously described [7,8]. Post-hemorrhagic acute hydrocephalus was treated with external ventricular or lumbar drainage. ...
Article
Contrary to aneurysmal bleeding, non-aneurysmal non-traumatic subarachnoid hemorrhage (NASAH) is rarely associated with unfavorable clinical outcome, cerebral infarction and vasospasm. We aimed to identify independent predictors for a poor clinical course and outcome after NASAH. All patients with NASAH treated at our institution between January 2005 and December 2012 were retrospectively analyzed. Collected demographic, clinical and radiographic variables were divided into primary (admission) and secondary (follow-up) parameters. Independent predictors of unfavorable outcome (defined as modified Rankin scale=3-6), cerebral infarction and development of vasospasm were identified. In addition, a risk score for the estimation of clinical outcome was designed. Out of population with 157 NASAH patients, unfavorable outcome was documented in 57 cases (36.3%) at discharge and in 17 cases (10.8%) after 6 months. Cerebral infarction(s) were found in 7 patients (4.3%). In multivariate analyses, higher age (≥65 years), poorer initial clinical condition measured by Hunt & Hess grade and diffuse basal bleeding pattern were independent outcome predictors and therefore included in the risk score (1-8 points). The risk score correlated with outcome at discharge (p<0.0001) and clinical improvement after 6 months (p=0.0238). A diffuse basal bleeding pattern predicted the detection of vasospasm by transcranial Doppler (p=0.001). Poor initial clinical condition (p=0.028) and vasospasm (p=0.031) were associated with the occurrence of cerebral infarction. NASAH patients with higher age, bad clinical condition on admission and diffuse bleeding pattern are prone to unfavorable outcome. The proposed risk score helps to identify patients with poor prognosis after NASAH.
... Our diagnostic and treatment algorithms for ruptured aneurysm(s) as well as intensive care unit (ICU) treatment strategy have already been described in detail previously [10,11]. The following aspects of SAH management are worth mentioning. ...
... For the documentation of CI and its time of occurrence, all 2438 follow-up CT scans within 6 weeks after SAH (mean of four scans per patient, range [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] were reviewed by one of the authors (R.J.) blinded at this time for any clinical information. The results obtained were subsequently correlated with original radiological reports. ...
Article
Cerebral infarction is a frequent and serious complication of aneurysmal subarachnoid hemorrhage (SAH). This study aimed to identify independent predictors of the timing of cerebral infarction and clarify its impact on disease course and patients' outcome. All consecutive patients with SAH admitted to our institution from January 2005 to December 2012 were analyzed. Serial computed tomography (CT) scans were evaluated for cerebral infarctions. Demographic, clinical, laboratory and radiological data of patients during hospitalization as well as clinical follow-ups 6 months after SAH were recorded. Of the 632 analyzed patients, 320 (51%) developed cerebral infarction on CT scans. 136 patients (21.5%) with early cerebral infarction (occurring within 3 days after SAH) had a significantly higher risk of unfavorable outcome than patients with late infarction [odds ratio (OR) 2.94; P = 0.008], a higher in-hospital mortality (OR 3.14; P = 0.0002) and poorer clinical outcome after 6 months (OR 0.54; P < 0.0001). The rates of decompressive craniectomy (OR 1.96, P = 0.0265), tracheostomy (OR 1.87, P = 0.0446), the duration of intensive care unit stay and mechanical ventilation were significantly higher in patients with early infarction. In multivariate analysis, Hunt and Hess grades 4 and 5 (OR 2.06, P = 0.008), Fisher grades 3 and 4 (OR 3.99, P = 0.014), sustained elevations of intracranial pressure >20 mmHg (OR 5.95, P < 0.0001) and early vasospasm on diagnostic angiograms (OR 3.01, P = 0.008) were predictors of early cerebral infarction. Early cerebral infarction after SAH is associated with severe clinical course and unfavorable outcome and can be reliably predicted by poor initial clinical condition, thick subarachnoid clot, early angiographic vasospasm and sustained elevations of intracranial pressure. © 2015 EAN.
... The sensitivity, specificity, negative predictive value, and positive predictive value of three-dimensional subtraction CTA were all found to be 100 % in a study by Li et al. [22]. In patients with non-traumatic subarachnoid hemorrhage who had both CTA and conventional angiography, CTA was found to have a significant role in reducing the collective effective radiation dose with no additional associated harms [23]. Almandoz et al. assessed the diagnostic accuracy of CTA in the evaluation of spontaneous intraparenchymal cerebral hemorrhage [24]. ...
Article
Background Intracranial hemorrhage is a commonly encountered medical problem frequently evaluated by computed tomography angiography (CTA). In CTA, there is radiation exposure and possible adverse effects of intravenous contrast administration. Therefore, the yield of this diagnostic tool needs to be explored in a heterogeneous group of daily encountered patients to provide insight into the risks and benefits of CTA. Objective To evaluate the role of cerebral CTA in patients with CT-confirmed or clinically suspected intracranial hemorrhage. Methods This retrospective study included all patients who underwent cerebral CTA for evaluation of intracranial hemorrhage that was diagnosed by a plain CT scan or suspected clinically from January 1, 2010, to May 30, 2018. All the scans were evaluated for abnormalities of the cerebral arteries in the CTA. Results One hundred twenty patients were included, 74 % were males, and the mean age was 46 years. Approximately 18 % were trauma patients. Overall, CTA was abnormal in 52 % of cases, aneurysms were found in 27 %, and arteriovenous malformation (AVM) in 8 %. Among 82 patients who had a hemorrhage on the plain CT scans, 54 % had normal CTA, 28 % showed aneurysm, and 11 % showed AVM. In trauma patients, the most common CTA finding was normality (48 %), followed by aneurysms (19 %) and dissection (14 %). In non-trauma patients, the most common CTA finding was normality (49 %), followed by aneurysms (28 %) and AVM (10 %). Conclusions CTA is a valuable diagnostic tool for intracranial hemorrhage because it detected abnormalities related to the hemorrhage in 42 % of patients. However, because more than half (58 %) of the patients had normal CTAs or showed CTA findings that were not relevant to the hemorrhage, clinical judgment should be exhausted before exposing them to radiation and intravenous contrast risks.
... Clinical management of SAH patients at our institution has been described previously. 8,9 In short, all patients were initially admitted to our neurocritical care unit. Ruptured aneurysms were treated by clipping or coiling after interdisciplinary assessment. ...
Article
BACKGROUND Along with subarachnoid hemorrhage (SAH), a ruptured aneurysm may also cause an intracerebral hematoma (ICH), which negatively impacts the functional outcome of SAH. OBJECTIVE To identify independent risk factors of aneurysmal ICH. METHODS Six hundred thirty-two consecutive patients with aneurysmal SAH treated at our institution from January 2005 to December 2012 were eligible for this study. Demographic parameters and preexisting comorbidities of patients, as well as various clinical and radiographic characteristics of SAH were correlated with the incidence and volume of aneurysmal ICH. RESULTS One hundred fifty-five patients (25%) had ICH on initial computed tomography with a mean volume of 26.7 mL (±26.8 mL). Occurrence and volume of ICH were associated with the location (distal anterior or middle cerebral artery >proximal anterior cerebral or internal carotid artery >posterior circulation, P < .001/P < .001) and size (>12 mm, P = .026/P < .001) of the ruptured aneurysm. Vascular risk factors independently increased the risk of ICH as well (arterial hypertension: odds ratio [OR] = 1.62, P = .032; diabetes mellitus: OR = 3.06, P = .009), while the use of aspirin (P = .037) correlated with the volume of ICH. The predictors of ICH were included into a risk score (0-9 points) that strongly predicted the occurrence of ICH (P = .01). Poor functional outcome after SAH was independently associated with the occurrence of ICH (P = .003, OR = 2.77) and its volume (P = .001, OR = 1.07 per-mL-increase). CONCLUSION Aneurysmal ICH is strongly associated with poorer functional outcome and seems to be predictable even before the bleeding event. The proposed risk factors for aneurysmal ICH require further validation and may be considered for treatment decisions regarding unruptured intracranial aneurysms.
... Our SAH management policy has been described in more detail previously. 14,15 Here, we focus on essential aspects. ...
Article
Cerebral infarction (CI) is a crucial complication of aneurysmal subarachnoid hemorrhage (SAH) associated with poor clinical outcome. We aimed at developing an early risk score for CI based on clinical characteristics available at the onset of SAH. Out of a database containing 632 consecutive patients with SAH admitted to our institution from January 2005 to December 2012, computed tomography (CT) scans up to day 42 after ictus were evaluated for CIs. Different parameters from admission up to aneurysm treatment were collected with subsequent construction of a risk score. Seven clinical characteristics were independently associated with CI and included in the Risk score (BEHAVIOR Score, 0 to 11 points): Blood on CT scan according to Fisher grade ⩾3 (1 point), Elderly patients (age ⩾55 years, 1 point), Hunt&Hess grade ⩾4 (1 point), Acute hydrocephalus requiring external liquor drainage (1 point), Vasospasm on initial angiogram (3 points), Intracranial pressure elevation >20 mm Hg (3 points), and treatment of multiple aneurysms ('Overtreatment', 1 point). The BEHAVIOR score showed high diagnostic accuracy with respect to the absolute risk for CI (area under curve=0.806, P<0.0001) and prediction of poor clinical outcome at discharge (P<0.0001) and after 6 months (P=0.0002). Further validation in other SAH cohorts is recommended.Journal of Cerebral Blood Flow & Metabolism advance online publication, 29 April 2015; doi:10.1038/jcbfm.2015.81.
... When accounting for the determined reduction in radiation exposure and reduced risk of complications related to conventional angiography, which may be avoided by first obtaining a CTA, the costs were V43,406.42 per QALY. 31 This figure falls under the generally accepted willingness-to-pay threshold for an innovation. ...
Article
Innovation to improve patient care quality is a priority of the neurosurgical specialty since its beginnings. As the strain on health care resources increases, the cost of these quality improvements is becoming increasingly important. The aims of this article are to review the available tools for assessing the cost of quality improvement along with the willingness to pay and to provide a conceptual framework for the assessment of innovations in terms of quality and economic metrics and provide examples from the neurosurgical literature. Copyright © 2015 Elsevier Inc. All rights reserved.
Article
Cost and value are increasingly important components of health care discussions. Despite a plethora of cost and cost-effectiveness analyses in many areas of medicine, there has been little of this type of research for neurosurgical procedures. This scarcity is vexing because this specialty represents one of the most expensive areas in medicine. This article discusses the general principles of cost-effectiveness analyses and reviews the cost- and cost-effectiveness-related research to date in neurosurgical subspecialties. The need for standardization of cost and cost-effectiveness measurement and reporting within neurosurgery is highlighted and a set of metrics for this purpose is defined. Copyright © 2015 Elsevier Inc. All rights reserved.
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Background and purpose: The use of iodinated contrast-enhanced imaging studies is increasing in acute cerebrovascular diseases, especially in subarachnoid hemorrhage (SAH). In SAH, such studies are essential for both diagnosis and treatment of the cause and sequela of hemorrhage. These patients are often subjected to multiple contrast studies such as computed tomographic angiography, computed tomographic perfusion, and cerebral angiography. They are also predisposed to intravascular volume depletion as a part of the disease process from cerebral salt wasting (CSW) and as a result of multiple contrast exposure can develop contrast-induced nephropathy (CIN). Data regarding CIN in this population are scarce. We aimed to examine the incidence of CIN in SAH and identify potential associative risk factors. Methods: We analyzed data from a prospectively collected patient database of patients with SAH admitted to the neurocritical intensive care unit in a single center over a period of 1 year. CIN was defined as an increase in serum creatinine by >1.5 times or >0.3 mg/dl greater than the admission value, or urine output <0.5 ml/kg/h during one 6-h block. Results: In this cohort of 75 patients with SAH who had undergone at least one contrast study, the mean age was 57.3 ± 15.6 years and 70.7% were women. Four percent developed CIN which resolved within 72 h and none required renal replacement therapy or dialysis. Patients older than 75 years (20%, p < 0.05), those with borderline renal function (14.3%, p = 0.26), diabetics (11.1%, p = 0.32), and those with lower recommended "maximum contrast dose" volume (33.3%, p = 0.12) had a trend toward development of CIN, although most were not statistically significant. Twenty-seven patients (36 %) were on 3% hypertonic saline (HTS) for CSW during the contrasted study but none developed CIN. Conclusions: The incidence of CIN in SAH patients is comparable to previously published reports on non-neurological cohorts. No definite association was noted with any predisposing factors postulated to be responsible for CIN, except for advanced age. Concurrent use of 3% HTS was not associated with CIN in this population.
Article
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Background: Intracranial aneurysm with and without subarachnoid haemorrhage (SAH) is a relevant health problem: The overall incidence is about 9 per 100,000 with a wide range, in some countries up to 20 per 100,000. Mortality rate with conservative treatment within the first months is 50-60%. About one third of patients left with an untreated aneurysm will die from recurrent bleeding within 6 months after recovering from the first bleeding. The prognosis is further influenced by vasospasm, hydrocephalus, delayed ischaemic deficit and other complications. The aim of these guidelines is to provide comprehensive recommendations on the management of SAH with and without aneurysm as well as on unruptured intracranial aneurysm. Methods: We performed an extensive literature search from 1960 to 2011 using Medline and Embase. Members of the writing group met in person and by teleconferences to discuss recommendations. Search results were graded according to the criteria of the European Federation of Neurological Societies. Members of the Guidelines Committee of the European Stroke Organization reviewed the guidelines. Results: These guidelines provide evidence-based information on epidemiology, risk factors and prognosis of SAH and recommendations on diagnostic and therapeutic methods of both ruptured and unruptured intracranial aneurysms. Several risk factors of aneurysm growth and rupture have been identified. We provide recommendations on diagnostic work up, monitoring and general management (blood pressure, blood glucose, temperature, thromboprophylaxis, antiepileptic treatment, use of steroids). Specific therapeutic interventions consider timing of procedures, clipping and coiling. Complications such as hydrocephalus, vasospasm and delayed ischaemic deficit were covered. We also thought to add recommendations on SAH without aneurysm and on unruptured aneurysms. Conclusion: Ruptured intracranial aneurysm with a high rate of subsequent complications is a serious disease needing prompt treatment in centres having high quality of experience of treatment for these patients. These guidelines provide practical, evidence-based advice for the management of patients with intracranial aneurysm with or without rupture. Applying these measures can improve the prognosis of SAH.
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Rebleeding after initial aneurysmal subarachnoid hemorrhage (SAH) can have substantial impact on overall patient outcome. While older studies have suggested rebleeding occurs in about 4% of patients during the first day after initial aneurysmal bleed, these studies may have failed to capture very early rebleeds and, consequently, underestimated the impact of rebleeding. An electronic literature search was performed to identify English-language articles published or available for review from February 1975 through October 2010. A total of 43 articles (40 original research and 3 review articles) focused on rebleeding after initial aneurysmal SAH in humans were selected for review. Although most studies supported an incidence of rebleeding ≤4%, studies investigating ultra-early rebleeding reported bleeding within the first 24 h following aneurysmal SAH in as many as 9-17% of patients, with most cases occurring within 6 h of initial hemorrhage. Overall, studies investigating antifibrinolytic therapy to reduce rebleeding have failed to clearly demonstrate overall therapeutic benefit. Short-course antifibrinolytic therapy may have a role prior to initial aneurysm repair, although insufficient data are currently available.
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To calculate the sensitivity and specificity of computed tomographic (CT) angiography in the diagnosis of cerebral aneurysms in patients with acute subarachnoid hemorrhage (SAH) at presentation. A systematic search for relevant studies was performed of the PubMed/MEDLINE and EMBASE databases. Two reviewers independently assessed the methodologic quality of each study by using the Quality Assessment of Diagnostic Accuracy Studies tool. The inclusion criteria were met by 50 studies. Heterogeneity was tested, and the presence of publication bias was visually assessed (by using a funnel plot). A meta-analysis of the reported sensitivity and specificity of each study with 95% confidence intervals (CIs) was performed on a per-patient level. Concerning sensitivity, the selected studies showed moderate heterogeneity. For specificity, low heterogeneity was observed. Moderate-heterogeneity studies that investigated only sensitivity or specificity were excluded from the pooled analyses by using a bivariate random effects model. The majority of the studies (n = 30) used a four-detector row CT scanner. The studies had good methodologic quality. Pooled sensitivity was 98% (95% CI: 97%, 99%), and pooled specificity was 100% (95% CI: 97%, 100%). Potential sources of variability among the studies were variations in the methodologic features (quality score), CT examination procedure (number of rows on the multidetector CT scanner), the standard of reference used, and the prevalence of ruptured intracranial aneurysms. There was evidence for publication bias, which may have led to overestimation of the diagnostic accuracy of CT angiography. Multidetector CT angiography can be used as a primary examination tool in the diagnostic work-up of patients with SAH.
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CTA is becoming the frontline modality to reveal aneurysms in patients with SAH. However, in about 20% of SAH patients no aneurysm is found. In these cases, intra-arterial DSA is still performed. Our aim was to evaluate whether negative findings on CTA can reliably exclude aneurysms in patients with acute SAH. We conducted a retrospective analysis of all negative findings on CTAs performed from 2005 to 2009 in patients with spontaneous SAH. Findings were compared with DSA. CTAs were performed with a 64-section multidetector row CT scanner. One hundred ninety-three patients with SAH and negative findings on CTA who underwent subsequent DSA were identified. The distribution of blood on unenhanced CT was the following: PMH in 93 patients, diffuse aneurysmal pattern in 50, no blood on CT (xanthochromic LP) in 32, and peripheral sulcal distribution in 18. All patients with PMH had negative findings on DSA. One patient with no blood on CT had vasculitis on DSA. Six of 18 (33%) patients with peripheral blood had vasculitis on DSA. Three of these were also diagnosed by CTA. All except 1 patient with diffuse aneurysmal blood had negative findings on DSA. One patient was diagnosed with an aneurysm on DSA (1/50, 0.5%). Repeat delayed DSA performed in 28 of these patients revealed a small aneurysm in 4 (14%). Five patients had a complication of DSA (2.6%); 1 was a clinical stroke (0.5%). In patients with SAH, negative CTA findings are reliable in ruling out aneurysms in the PMH pattern or no blood on CT. DSA is indicated in the diffuse aneurysmal pattern of SAH, and repeat delayed DSA is required if the initial DSA findings are negative. When the blood is peripheral, CTA should be scrutinized for vasculitis and DSA is recommended for confirmation.
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The objective of this study was to determine the radiation dose delivered during comprehensive computed tomography (CT) imaging for acute stroke. All CT examinations performed over 18 months using our acute stroke protocol were included. Protocol includes an unenhanced CT head, CT angiography from the arch to vertex, CT perfusion/permeability, and an enhanced CT head. All imaging was acquired with a 64-MDCT. Examinations where any element of the protocol was repeated or omitted due to mistimed injection or patient motion were excluded. Dose-length products (DLP) for all components of each examination were obtained from dose reports generated at the time of acquisition, separating neck, and head calculations. Effective doses for each examination were calculated using the DLP and normalized values of effective dose per DLP appropriate for the body regions imaged. Ninety-five examinations were included. Mean DLP was 6,790.0 mGy x cm. Effective doses ranged from 11.8 to 27.3 mSv, mean effective dose of 16.4 mSv. Mean effective dose for acquisition of the unenhanced head was 2.7 mSv. Largest contribution to effective dose was the CTA with a mean effective dose of 5.4 mSv. Mean effective dose for the CT perfusion was 4.9 mSv. A comprehensive CT acute stroke protocol delivered a mean effective dose of 16.4 mSv, which is approximately six times the dose of an unenhanced CT head. These high-dose results must be balanced with the benefits of the detailed anatomic and physiologic data obtained. Centers should implement aggressive dose reduction strategies and freely use MR as a substitute.
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From 1979-85, 2435 patients with a transient ischaemic attack or minor ischaemic stroke were randomly allocated to receive long term "blind" treatment with aspirin 600 mg twice daily (n = 815), aspirin 300 mg once daily (n = 806) or placebo (n = 814). No patient was lost to follow up. The "intention to treat" comparison included all the serious vascular events and deaths which occurred before the end of the follow up period on 30 September 1986. There was no difference in efficacy between the 300 mg and 1200 mg daily doses of aspirin, but the lower dose was undoubtedly less gastrotoxic. Also, there was no definite difference in the response of males and females to aspirin. The odds of suffering a major stroke, myocardial infarction or vascular death were 15% less in the combined aspirin groups compared with the placebo group (95% confidence interval 29% reduction to 3% increase in odds) which is compatible with the continuing overview of all the similar trials of antiplatelet drugs where the relative reduction in odds was 25%. There was no statistically significant reduction in the likelihood of either disabling major stroke and vascular death or vascular death occurring.
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We sought to establish whether CT angiography (CTA) can be applied to the planning and performance of clipping or coiling in ruptured intracranial aneurysms without recourse to intraarterial digital subtraction angiography (IA-DSA). Over the period April 2003 to January 2006 in all patients presenting with a subarachnoid haemorrhage CTA was performed primarily. If CTA demonstrated an aneurysm, coiling or clipping was undertaken. IA-DSA was limited to patients with negative or inconclusive CTA findings. We compared CTA images with findings at surgery or coiling in patients with positive CTA findings and in patients with negative and inconclusive findings in whom IA-DSA had been performed. In this study, 224 consecutive patients (mean age 52.7 years, 135 women) were included. In 133 patients (59%) CTA demonstrated an aneurysm, and CTA was followed directly by neurosurgical (n = 55) or endovascular treatment (n = 78). In 31 patients (14%) CTA findings were categorized as inconclusive, and in 60 (27%) CTA findings were negative. One patient received surgical treatment on the basis of false-positive CTA findings. In 17 patients in whom CTA findings were inconclusive, IA-DSA provided further diagnostic information required for correct patient selection for any therapy. Five ruptured aneurysms in patients with a nonperimesencephalic SAH were negative on CTA, and four of these were also false-negative on IA-DSA. On a patient basis the positive predictive value, negative predictive value, sensitivity, specificity and accuracy of CTA for symptomatic aneurysms were 99%, 90%, 96%, 98% and 96%, respectively. CTA should be used as the first diagnostic modality in the selection of patients for surgical or endovascular treatment of ruptured intracranial aneurysms. If CTA renders inconclusive results, IA-DSA should be performed. With negative CTA results the complementary value of IA-DSA is marginal. IA-DSA is not needed in patients with negative CTA and classic perimesencephalic SAH. Repeat IA-DSA or CTA should still be performed in patients with a nonperimesencephalic SAH.
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The purpose of this work was to assess intertechnique and interobserver reproducibility of 64-row multisection CT angiography (CTA) used to detect and evaluate intracranial aneurysms. From October 2005 to November 2006, 54 consecutive patients with nontraumatic subarachnoid hemorrhage (SAH) underwent both CTA and digital substraction angiography (DSA). Four radiologists independently reviewed CT images, and 2 other radiologists reviewed DSA images. Aneurysm diameter (D), neck width (N), and the presence of a branch arising from the sac were assessed. DSA revealed 67 aneurysms in 48 patients and no aneurysm in 6 patients. Mean sensitivity and specificity of CTA for the detection of intracranial aneurysms were, respectively, 94% and 90.2%. For aneurysms less than 3 mm, CTA had a mean sensitivity of 70.4%. Intertechnique and interobserver agreements were good for the detection of aneurysms (mean kappa = 0.673 and 0.732, respectively) and for the measurement of their necks (mean kappa = 0.753 and 0.779, respectively). Intertechnique and interobserver agreements were excellent for the measurement of aneurysm diameters (mean kappa = 0.847 and 0.876, respectively). In addition, CTA was accurate in determining the N/D ratio of aneurysms and adjacent arterial branches. However, the N/D ratio was overestimated by all of the readers at CTA. Sixty-four-row multisection CTA is an imaging method with a good interobserver reproducibility and a high sensitivity and specificity for the detection and the morphologic evaluation of ruptured intracranial aneurysms. It may be used as an alternative to DSA as a first-intention imaging technique in patients with SAH.
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Background and purpose: Both CT angiography and digital subtraction angiography are used to detect aneurysms in patients with subarachnoid hemorrhage. We examined a large multihospital data base to determine how practice is evolving with regard to the use of CT angiography and DSA in patients with ruptured cerebral aneurysm. Materials and methods: The Premier Perspective data base was used to identify hospitalizations of patients treated with clipping or coiling of ruptured cerebral aneurysms from 2006-2011. Billing information was used to determine pretreatment and posttreatment use of DSA and CT angiography during hospitalization. Results: A total of 4972 patients (1022 clipping, 3950 coiling) at 116 hospitals were identified. The percentage of patients with SAH who underwent pretreatment CT angiography significantly increased from 20% in 2006 to 44% in 2011 (P < .0001), whereas the percentage of patients who underwent DSA remained unchanged from 96-94% (P = .28). This CT angiography trend was observed in coiling patients (17-42%, P < .0001) and clipping patients (32-54%, P < .0001). There was a significant increase in the percentage of patients who underwent posttreatment imaging from 41% in 2006 to 48% in 2011 (P = .0037). This trend was observed in clipping patients (33-65%, P < .0001) but not coiling patients (43-45%, P = .62). Conclusions: For the pretreatment evaluation of ruptured aneurysms, the use of CT angiography increased from 2006-2011 without a corresponding decrease in the use of DSA. These results raise the question of potential redundancy without added clinical value of the second test.
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Background: Recent studies have documented the high sensitivity of computed tomography angiography (CTA) in detecting a ruptured aneurysm in the presence of acute subarachnoid hemorrhage (SAH). The practice of digital subtraction angiography (DSA) when CTA does not reveal an aneurysm has thus been called into question. Objective: We examined this dilemma from a cost-effectiveness perspective by using current decision analysis techniques. Methods: A decision tree was created with the use of TreeAge Pro Suite 2012; in 1 arm, a CTA-negative SAH was followed up with DSA; in the other arm, patients were observed without further imaging. Based on literature review, costs and utilities were assigned to each potential outcome. Base-case and sensitivity analyses were performed to determine the cost-effectiveness of each strategy. A Monte Carlo simulation was then conducted by sampling each variable over a plausible distribution to evaluate the robustness of the model. Results: With the use of a negative predictive value of 95.7% for CTA, observation was found to be the most cost-effective strategy ($6737/Quality Adjusted Life Year [QALY] vs $8460/QALY) in the base-case analysis. One-way sensitivity analysis demonstrated that DSA became the more cost-effective option if the negative predictive value of CTA fell below 93.72%. The Monte Carlo simulation produced an incremental cost-effectiveness ratio of $83 083/QALY. At the conventional willingness-to-pay threshold of $50 000/QALY, observation was the more cost-effective strategy in 83.6% of simulations. Conclusion: The decision to perform a DSA in CTA-negative SAH depends strongly on the sensitivity of CTA, and therefore must be evaluated at each center treating these types of patients. Given the high sensitivity of CTA reported in the current literature, performing DSA on all patients with CTA negative SAH may not be cost-effective at every institution.
Article
This study was undertaken to determine the incidence, risk factors, and in-hospital outcome of nephropathy requiring dialysis (NRD) after percutaneous coronary intervention (PCI), and to evaluate the role of a weight- and creatinine-adjusted maximum radiographic contrast dose (MRCD) on NRD. Data were obtained from a registry of 16,592 PCIs. The data were divided into development and test sets. Univariate predictors were identified and a multivariate logistic regression model was developed. The MRCD was calculated for each patient as: MRCD = 5 ml x body weight (kilograms)/serum creatinine (milligrams per deciliter). Predictive accuracy was assessed by receiver-operating characteristic curve analysis. In the development set, 41 patients (0.44%) developed NRD with a subsequent in-hospital mortality rate of 39.0%. NRD increased with worsening baseline renal dysfunction. Other risk factors included peripheral vascular disease, diabetes mellitus, congestive heart failure, and cardiogenic shock. There was a direct relation between the number of risk factors and NRD. After adjustment for baseline risk factors, MRCD was the strongest independent predictor of NRD (adjusted odds ratio 6.2, 95% confidence interval 3.0 to 12.8). NRD and in-hospital mortality were both significantly higher in patients who exceeded the MRCD compared with patients who did not (p <0.001). In conclusion, NRD following PCI is a rare complication with a poor prognosis. Baseline clinical characteristics identify patients at greatest risk for NRD. Optimization of procedural variables such as timing of the intervention relative to the diagnostic catheterization, staging coronary procedures, or dosing within the MRCD may help reduce the risk of this complication in high-risk patients. A risk prediction tool for NRD with guidelines for prevention is presented.
Article
Aim: To determine the negative predictive value of 16 channel multisection computed tomography angiography (CTA) for detecting aneurysms in spontaneous subarachnoid haemorrhage (SAH), using digital subtraction angiography (DSA) as the reference standard. Materials and methods: The prospectively collected cerebral angiogram database of Department of Neuroradiology, Atkinson Morley Regional Neuroscience Centre was used to identify 200 consecutive patients who had undergone DSA for SAH. Of these, 176 had undergone CTA prior to DSA. Clinical details and radiology reports were correlated and images of positive investigations reviewed. Results: DSA showed one or more cerebral aneurysms in 105 (60%) patients. These were correctly reported on CTA in 100. CTA was reported negative for aneurysms in 74 patients. Of these five were false negative and had aneurysms detected on DSA. In the CTA/DSA negative group, 11 (16%) patients had classical perimesencephalic clinical syndrome and blood distribution. There were two false positives at CTA. For ruptured cerebral aneurysms, CTA had 95.2% sensitivity, 97.2% specificity, 98.1% positive predictive value, and 93.2% negative predictive value. Conclusion: The sensitivity and negative predictive value of CTA for ruptured aneurysms remains imperfect. Continued use of DSA is recommended in most patients with a negative CTA after acute SAH. Confirmation of a negative CTA result with DSA may not be routinely required in patients with perimesencephalic syndrome.
Article
Objectives: Diagnosing subarachnoid hemorrhage (SAH) in emergency department (ED) patients is challenging. Potential diagnostic strategies include computed tomography (CT) only, CT followed by lumbar puncture (CT/LP), CT followed by magnetic resonance imaging and angiography (CT/MRA), and CT followed by CT angiography (CT/CTA). The objective was to determine the relative cost-effectiveness of diagnostic strategies for SAH. Methods: The authors created a decision model to evaluate the cost-effectiveness of SAH diagnostic strategies in ED patients with suspected SAH. Clinical probabilities were obtained from published data; sensitivity analyses were conducted across plausible ranges. Results: In the base-case scenario, CT-only had a cost of $10,339 and effectiveness of 20.25 quality-adjusted life-years (QALYs), and CT/LP had a cost of $15,120 and effectiveness of 20.366 QALYs. Among the alternative strategies, CT/CTA had a cost of $12,840 and effectiveness of 20.24 QALYs, and CT/MRA had a cost of $16,207 and effectiveness of 20.27 QALYs. In sensitivity analyses, probability of severe disability from SAH, sensitivity of noncontrast CT, and specificity of LP and MRA were key drivers of the model, and CT-only and CT/LP were preferable. Conclusions: In the base-case scenario, CT-only was preferable to the CT/CTA and CT/MRA strategies. When considering sensitivity analyses and the current medicolegal environment, there are no overwhelming differences between the cost-effectiveness of CT/LP and the alternative strategies to suggest that clinicians should abandon the standard CT/LP approach.
Article
Cost-utility analysis, which measures the effectiveness of health care projects in terms of the cost per quality adjusted life-year (QALY) gained, has been used to compare radiation protection measures in diagnostic radiology with established medical procedures. Despite large uncertainties in these evaluations the results suggest that patient dose reductions effected by the use of carbon fibre components in diagnostic imaging systems can be at least as cost-effective as many diagnostic and surgical procedures that already consume a considerable amount of health service resources.
Chapter
The basic framework for Radiation Protection, according to ICRP, is based on three fundamental principles; justification, optimisation and limitation. The second principle, optimisation, is where the medical physicist can have the greatest influence. Briefly, the principle states that doses should be kept As Low as Reasonably Achievable (ALARA).
Article
The aim of this guideline is to present current and comprehensive recommendations for the diagnosis and treatment of aneurysmal subarachnoid hemorrhage (aSAH). A formal literature search of MEDLINE (November 1, 2006, through May 1, 2010) was performed. Data were synthesized with the use of evidence tables. Writing group members met by teleconference to discuss data-derived recommendations. The American Heart Association Stroke Council's Levels of Evidence grading algorithm was used to grade each recommendation. The guideline draft was reviewed by 7 expert peer reviewers and by the members of the Stroke Council Leadership and Manuscript Oversight Committees. It is intended that this guideline be fully updated every 3 years. Evidence-based guidelines are presented for the care of patients presenting with aSAH. The focus of the guideline was subdivided into incidence, risk factors, prevention, natural history and outcome, diagnosis, prevention of rebleeding, surgical and endovascular repair of ruptured aneurysms, systems of care, anesthetic management during repair, management of vasospasm and delayed cerebral ischemia, management of hydrocephalus, management of seizures, and management of medical complications. aSAH is a serious medical condition in which outcome can be dramatically impacted by early, aggressive, expert care. The guidelines offer a framework for goal-directed treatment of the patient with aSAH.
Article
Contrast media is administered to many patients in hospitals nationwide. Although the use of contrast and dyes is widespread and has a well accepted use among the medical profession, contrast-induced nephropathy can be a common and potentially harmful complication. Identifying patients at risk, attempting to minimize risk, and using preventative strategies should be priorities to decrease the harmful effects that are associated with the administration of contrast media. This article provides a general overview of contrast-induced nephropathy and a brief review of the risk factors and prophylactic treatment.
Article
Measurement of health-related quality of life can play a major role in benefit-risk assessment. Preference-based methods for measuring quality of life where data are aggregated into a single quality of life index are particularly well suited for use in quantitative analysis. Using two examples from research on cancer and multiple sclerosis, this paper compares approaches in which quality of life data from genuine studies or from external sources is used. It will be demonstrated that quality of life data can provide relevant information for quantitative benefit-risk assessment in applied research. In addition, quality of life data may be included in more complex approaches of multi-criteria decision analysis. Copyright © 2011. Published by Elsevier GmbH.
Article
Cerebral aneurysms can cause substantial morbidity and mortality, specifically if they rupture, leading to nontraumatic subarachnoid hemorrhage (SAH). This meta-analysis summarizes evidence about the accuracy of noninvasive computed tomographic (CT) angiography for diagnosing intracranial aneurysms in symptomatic patients. Four databases including PubMed were searched without language restrictions from January 1995 to February 2010. Two independent reviewers selected and extracted 45 studies that compared CT angiography with digital subtraction angiography (DSA) and/or intraoperative findings in patients suspected of having cerebral aneurysms. Data from eligible studies were used to reconstruct 2 x 2 contingency tables on a per-patient basis in at least 5 diseased and 5 nondiseased patients, with additional data on a per-aneurysm basis when available. The 45 included studies generally were of high methodological quality. Among the 3,643 patients included, about 86% had nontraumatic SAH, and 77% had cerebral aneurysms. Overall, CT angiography had a pooled sensitivity of 97.2% (95% confidence interval, 95.8-98.2%) for detecting and specificity of 97.9% (95.7-99.0%) for ruling out cerebral aneurysms on a per-patient basis. On a per-aneurysm basis, the pooled sensitivity was 95.0% (93.2-96.4%), and the specificity 96.2% (92.9-98.0%). The diagnostic accuracy of CT angiography with 16- or 64-row multidetector CT was significantly higher than that of single-detector CT, especially in detecting small aneurysms of ≤ 4 mm in diameter. CT angiography has a high accuracy in diagnosing cerebral aneurysms, specifically when using modern multidetector CT. In the future, CT angiography may increasingly supplement or selectively replace DSA in patients suspected of having a cerebral aneurysm.
Article
The only acceptable modality for imaging patients with intracranial aneurysms is that which detects the aneurysm quickly, reliably, and safely and guides the prompt proper therapy; in my experience, conventional angiography with digital subtraction angiography techniques usually comes closest to that ideal.
Article
To compare the cost-effectiveness of using selective computed tomographic (CT) strategies with that of performing CT in all patients with minor head injury (MHI). The internal review board approved the study; written informed consent was obtained from all interviewed patients. Five strategies were evaluated, with CT performed in all patients with MHI; selectively according to the New Orleans criteria (NOC), Canadian CT head rule (CCHR), or CT in head injury patients (CHIP) rule; or in no patients. A decision tree was used to analyze short-term costs and effectiveness, and a Markov model was used to analyze long-term costs and effectiveness. n-Way and probabilistic sensitivity analyses and value-of-information (VOI) analysis were performed. Data from the multicenter CHIP Study involving 3181 patients with MHI were used. Outcome measures were first-year and lifetime costs, quality-adjusted life-years, and incremental cost-effectiveness ratios. Study results showed that performing CT selectively according to the CCHR or the CHIP rule could lead to substantial U.S. cost savings ($120 million and $71 million, respectively), and the CCHR was the most cost-effective at reference-case analysis. When the prediction rule had lower than 97% sensitivity for the identification of patients who required neurosurgery, performing CT in all patients was cost-effective. The CHIP rule was most likely to be cost-effective. At VOI analysis, the expected value of perfect information was $7 billion, mainly because of uncertainty about long-term functional outcomes. Conclusion: Selecting patients with MHI for CT renders cost savings and may be cost-effective, provided the sensitivity for the identification of patients who require neurosurgery is extremely high. Uncertainty regarding long-term functional outcomes after MHI justifies the routine use of CT in all patients with these injuries.
Article
The purpose of this study was to evaluate the image quality, radiation dose, and diagnostic accuracy of dual-energy CT angiography (CTA) compared with 3D rotational digital subtraction angiography (DSA) in the detection of intracranial aneurysms. Forty-six patients with clinically suspected intracranial aneurysms underwent dual-source dual-energy CTA and 3D DSA. For the analysis of the image quality and radiation dose of dual-energy CTA, 46 patients who underwent digital subtraction CTA were recruited as a control group. The image quality of dual-energy CTA and digital subtraction CTA was rated on a 4-point scale as excellent, good, moderate, or poor. The radiation dose of CTA was recorded according to patient protocol. Aneurysm detection with dual-energy CTA compared with 3D DSA was analyzed on a per-patient and on a peraneurysm basis. Sensitivity, specificity, and positive and negative predictive values for aneurysm presence were determined. The mean maximum diameter and dome and neck dimensions of aneurysms were measured on dual-energy CTA and 3D DSA images. Correlation analysis between the two techniques was performed. There was no statistical difference between the image quality of dual-energy CTA and that of digital subtraction CTA (p>0.05). Patients undergoing dual-energy CTA received a smaller radiation dose (volume CT dose index, 20.6+/-0.1 mGy [mean+/-SD]; dose-length product, 398.6+/-19.0 mGy x cm) than those undergoing digital subtraction CTA (volume CT dose index, 50.4+/-3.4 mGy; dose-length product, 1,095.6+/-114.2 mGyxcm) (p<0.05). Three-dimensional DSA showed no aneurysm in 11 patients and 40 aneurysms in 35 patients. The mean maximum diameter of the aneurysms was 6+/-3 mm; the dome measurement, 5+/-3 mm; and the neck dimension, 3+/-2 mm. With dual-energy CTA, 38 aneurysms in 34 patients were correctly detected, and two aneurysms in two patients were missed. With DSA as the standard of reference, the sensitivity, specificity, and positive and negative predictive values of dual-energy CTA in the detection of intracranial aneurysm were 97.1%, 100%, 100%, and 91.7% on a per-patient basis and 95.0%, 100%, 100%, and 99.7% on a per-aneurysm basis. Dual-energy CTA had sensitivities of 93.8%, 100%, and 80.0% and specificities of 100%, 100%, and 100% in the detection of aneurysms larger than 5 mm, those measuring 3.1-5 mm, and aneurysms 3 mm or smaller. At dual-energy CTA, the mean maximum diameter and dome and neck dimensions were 6+/-3 mm, 5+/-3 mm, and 3+/-2 mm. Excellent correlation was found between DSA and dual-energy CTA findings with respect to mean maximum diameter and dome and neck dimensions (r=0.969, 0.957, and 0.870; p = 0.000). On the basis of the findings in the small series of patients evaluated, contrast-enhanced dual-energy CTA had diagnostic image quality at a lower radiation dose than digital subtraction CTA and high diagnostic accuracy compared with 3D DSA in the detection of intracranial aneurysms.
Article
No prospective study has reported the incidence of contrast-induced nephropathy (CIN) or the associated morbidity and mortality after contrast-enhanced computed tomography (CECT) in the outpatient setting. We enrolled and followed a prospective, consecutive cohort (June 2007 through January 2009) of patients who received intravenous contrast for CECT in the emergency department of a large, academic, tertiary care center. Outcomes measured were as follows (1) CIN: An increase in serum creatinine > or =0.5 mg/dl or > or =25% 2 to 7 d after contrast administration; (2) severe renal failure: An increase in serum creatinine to > or =3.0 mg/dl or the need for dialysis at 45 d; and (3) renal failure as a contributing cause of death (consensus of three independent physicians) at 45 d. The incidence of CIN was 11% (70 of 633) among the 633 patients enrolled. Fifteen (2%) patients died within 45 d, including six deaths after study-defined CIN. Seven (1%) patients developed severe renal failure, six of whom had study-defined CIN. Of the six patients with CIN and severe renal failure, four died, and adjudicators determined that renal failure significantly contributed to all four deaths. Thus, CIN was associated with an increased risk for severe renal failure and death from renal failure. CIN occurs in >10% of patients who undergo CECT in the outpatient setting and is associated with a significant risk for severe renal failure and death.
Article
The primary goal of this study was to determine the radiation dose received during diagnostic and interventional neuroangiographic procedures in a group of pediatric patients. A second goal was to approximate the total average radiation dose from all angiographic and CT studies that pediatric patients underwent during the study period and to estimate the increased risk of cancer incidence in this patient group. The study subjects were pediatric patients who had undergone one or more neuroangiographic procedures at Harborview Medical Center between December 1, 2004, and April 30, 2008. Recorded radiation doses were converted to entrance skin dose (ESD) and effective dose (ED) to indicate deterministic and stochastic damage, respectively. The Biologic Effects of Ionizing Radiation (BEIR) VII, phase 2, report was used to estimate the expected increased risk of cancer in the study population. For diagnostic and therapeutic procedures, a mean ED of 10.4 and 34.0 mSv per procedure was calculated, respectively. The ESD values proved too low to cause deterministic harm. The estimated number of excess cases of malignancy projected from the total average radiation exposure was 890.6 per 100,000 exposed male children and 1,222.5 per 100,000 exposed females, an overall increase of approximately 1% to the lifetime attributable risk of cancer. Although both angiography and CT have revolutionized the practice of medicine and confer benefits to patients, it is important that we continue to investigate the possible adverse effects of these technologies. Protocols that minimize radiation dose without compromising a study should be implemented.
Article
To define outcomes from contrast-induced nephropathy (CIN) after both intra-arterial and intravenous administration of contrast medium. We performed a retrospective case-matched cohort study at Mayo Clinic's site in Rochester, MN, from April 1, 2004, to March 31, 2006. All contrast procedures were evaluated for inclusion. Contrast-induced nephropathy was defined as creatinine elevation of 25% or more after contrast exposure or of more than 0.5 mg/dL within 7 days of contrast exposure. Cases of CIN were matched 1:3 with controls by age, sex, pre-procedure creatinine elevation, diabetes mellitus, and type of imaging procedure. A total of 809 patients who developed CIN were matched to 2427 patients who did not develop CIN after contrast exposure. In multivariate analyses, CIN was significantly associated with 30-day mortality (odds ratio, 3.37; 95% confidence interval [CI], 2.58-4.41; P<.001) and overall mortality (hazard ratio, 1.57; 95% CI, 1.32-1.86; P<.001) after adjustment for heart failure, hypertension, medications, total hydration, iodine load, prior contrast exposure, and all matched variables during the study period. Intravenous contrast administration was a risk factor for 30-day mortality (odds ratio, 2.91; 95% CI, 1.17-7.23; P=.02) and overall mortality (hazard ratio, 3.02; 95% CI, 1.89-4.82; P<.001) compared with intra-arterial administration of contrast after adjustment for heart failure, hypertension, medications, total hydration, iodine load, prior contrast exposure, and all matched variables during the study period. Contrast-induced nephropathy after administration of contrast medium is associated with increased mortality. This risk is higher in patients in whom contrast medium is administered intravenously than in those in whom it is administered intra-arterially.
Article
In 139 patients with preexisting abnormal renal function (serum creatinine level of 2.0 mg/dL or greater) undergoing cardiac angiography (141 examinations), the incidence of contrast nephropathy, defined as a 1 mg/dL or greater rise in serum creatinine, was 23% (95% confidence interval, 17% to 30%). Stepwise logistic regression analysis showed that contrast nephropathy was independently associated with class IV heart failure with low cardiac output (71% incidence in this subgroup; p less than 0.0001), multiple radiocontrast studies within 72 hours (50%; p = 0.002), dose of radiocontrast administered (p = 0.009), and insulin-dependent diabetes mellitus (44%; p = 0.007). Age, hypertension, and hyperuricemia were not associated. In patients without low cardiac output, other radiocontrast tests, or insulin-dependent diabetes mellitus, there was a 2% incidence of contrast nephropathy in those who received less than 125 mL radiocontrast and a 19% incidence in those who received 125 mL or greater.
Article
Patient radiation doses received during interventional radiological procedures can be significant. To aid in the establishment of reference dose levels, a patient dose survey has been conducted of such procedures. A total of 288 non-coronary procedures (177 classified as diagnostic and 111 as therapeutic) were accrued into the study. For each procedure, the fluoroscopy screening time and the fluoroscopic and digital radiographic dose-area products were recorded in a computer database. For example, median dose-area product values (due to fluoroscopy and digital radiography combined) of 24.2, 27.9, 69.6 and 74.7 Gy cm2 were obtained for nephrostomy, biliary stent removal/insertion, cerebral angiography and percutaneous transhepatic cholangiography procedures. While the effective dose is not an accurate measure of patient risk, it is convenient for comparing the radiological risks associated with various procedures. Effective doses were estimated from the total dose-area products. The respective median estimated effective dose values for the four procedures noted above were 3.9, 4.5, 7.0 and 12.0 mSv. While an infrequently performed procedure at this institution (n = 4 during this survey), the transjugular intrahepatic portosystemic shunt (TIPS) procedure had the greatest median dose-area product and effective dose values: 347 Gy cm2 and 55.5 mSv, respectively. Excluding the extreme case of TIPS, it was found that among commonly-performed procedures, those that are categorized as therapeutic do not necessarily present a statistically significant greater radiation risk than those which are diagnostic. Comparisons between dose-area product values obtained from this study are made with data from other interventional radiology patient dose surveys and reasons for some differences noted are discussed.
Article
A well-defined complication rate of cerebral angiography in patients with subarachnoid hemorrhage (SAH), cerebral aneurysm, and arteriovenous malformation (AVM) would be useful to physicians making decisions regarding the imaging of these patients. We sought to define a statistically significant complication rate through meta-analysis of prospective studies in the literature. Meta-analysis of 3 published prospective studies of complications in cerebral angiography was performed to specifically define the risk of cerebral angiography in patients presenting with SAH, cerebral aneurysm, and AVM. The complication rates for cerebral angiography in patients with SAH and AVM/aneurysm without SAH were compared with the complication rates in patients who underwent cerebral angiography for transient ischemic attack (TIA)/ischemic stroke with use of the Fisher exact test. The combined risk of permanent and transient neurological complication was significantly lower in patients with SAH compared with patients with TIA/stroke (1.8% versus 3.7%; P=0.03). The combined risk of permanent and transient neurological complication was significantly lower in patients with aneurysm/AVM without SAH compared with patients with TIA/stroke (0.3% versus 3.7%; P=0.001). When the patients with SAH and cerebral aneurysm/AVM were combined, the overall risk of permanent and transient neurological complication was significantly lower than for the TIA/stroke patients (0.8% versus 3.0%; P=0.001), as was the risk of permanent neurological complication (0.07% versus 0.7%; P=0.004). The risk of permanent neurological complication associated with cerebral angiography in patients with SAH, cerebral aneurysm, and AVM is quite low (0.07%). This risk is lower than previously recognized.
Article
To compare computed tomographic (CT) angiography and magnetic resonance (MR) angiography with intraarterial digital subtraction angiography (DSA) in the detection of intracranial aneurysms. One hundred forty-two patients underwent intraarterial DSA to detect aneurysms. CT angiography, three-dimensional time-of-flight MR angiography, and intraarterial DSA were performed contemporaneously. Film hard-copy images and maximum intensity projection reconstructions of the CT angiograms and MR angiograms were reviewed at different times. The accuracy per patient for the best observer was 0.87 at CT angiography and 0.85 at MR angiography. The accuracy per aneurysm for the best observer was 0.73 at CT angiography and 0.67 at MR angiography. Differences between readers and modalities were not significant. Interobserver agreement was good: kappa value of 0.73 for CT angiography and of 0.74 for MR angiography. The sensitivity for detection of aneurysms smaller than 5 mm was 0.57 for CT angiography and 0.35 for MR angiography compared with 0.94 and 0.86, respectively, for detection of aneurysms 5 mm or larger. The accuracy of both CT angiography and MR angiography was lower for detection of internal carotid artery aneurysms compared with that at other sites. With low observer confidence, the likelihood of correct interpretation was significantly poorer. CT angiography and MR angiography have limited sensitivity in the detection of small aneurysms but good interobserver agreement. There is no significant difference in diagnostic performance between the noninvasive modalities.
Article
The goal of this study was to assess the diagnostic accuracy of computerized tomography (CT) angiography performed with the aid of multislice technology (MSCT angiography) in the investigation of intracranial aneurysms, by comparing this method with intraarterial digital subtraction (IADS) angiography. Fifty consecutive adult patients, who successively underwent MSCT angiography (four rows) and IADS angiography of intracranial vessels, were prospectively identified. The MSCT angiography studies consisted of 1.25-mm slices, with 0.8-mm reconstruction intervals, a pitch of 0.75, and timing determined by a test bolus. Two neuroradiologists, who were blinded to the initial interpretation of the MSCT angiograms as well as to those of the IADS angiograms, independently reviewed the MSCT angiograms for the detection and characterization of intracranial aneurysms. Forty-nine intracranial aneurysms were identified in 40 patients; 33 of these lesions were responsible for subarachnoid hemorrhage. The sensitivity, specificity, and accuracy of MSCT angiography in the detection of intracranial aneurysms were 94.8, 95.2, and 94.9%, respectively, on a per-aneurysm basis and 99, 95.2, and 98.3%, respectively, on a per-patient basis. Interobserver agreement was 98%. There was an excellent correlation between aneurysm size assessed using MSCT angiography and that determined by IADS angiography (slope = 0.916, r = 0.877, p < 0.001); however, 2 mm stood as the cutoff size below which the sensitivity of MSCT angiography was statistically lower. That method displayed great accuracy in characterizing the morphological characteristics of the aneurysm. Multislice CT angiography is an accurate and robust noninvasive screening test for intracranial aneurysms. It performs better than that reported for single-slice CT angiography. Introduction of eight- and especially 16-row MSCT angiography will provide further progression through thinner slices, a lower pitch, and a purely arterial phase.
Article
Cerebral CT angiography (CTA) is an established method applied to both the detection and treatment planning of intracranial aneurysms. The aim of our study was to compare CTA and digital subtraction angiography (DSA) findings with the surgical results mainly in patients with acute SAH and to evaluate the clinical usefulness of CTA. During the last 2 years, 82 consecutive patients were admitted under clinical symptoms and signs suggestive of harboring an intracranial aneurysm. CT angiography performed immediately afterwards the plain CT, while DSA was performed within the first 48 h of admission. All aneurysms detected were confirmed during surgery or endovascular embolization. Repeat DSA was performed in all patients having both the initial CTA and the DSA 15 days after the onset of symptoms negative. CT angiograms and conventional angiographies were studied by a consensus of two radiologists for each technique, who performed aneurysm detection, morphological features characterization and evaluation of the technique. Surgical or/and endovascular treatment was performed in 45 patients and 53 aneurysms were confirmed. Using 3D-CT angiography, we detected 47 aneurysms in 42 patients. Conventional angiography depicted 43 aneurysms in 39 patients. The sensitivity of CTA for the detection of all aneurysms versus surgery was 88.7%, the specificity 100%, the positive predictive value (PPV) 100%, the negative predictive value (NPV) 80.7% and the accuracy 92.3%. Accordingly, the sensitivity of DSA was 87.8%, the specificity 98%, the PPV 97.7%, the NPV 89.1% and the accuracy 92.9%. Considering aneurysms > or =3 mm, CTA showed a sensitivity ranging from 93.3 to 100%, equal to that of DSA. Cerebral CT angiography has an equal sensitivity to DSA in the detection of intracranial aneurysms >3 mm. It has also 100% detection rate in AcoA and MCA bifurcation aneurysms, while some locations, like posterior communicating artery aneurysms, remain problematic. The delineating features of each aneurysm are better depicted with CTA due to 3D visualization. The use of digital subtraction angiography as a diagnostic tool can be limited in equivocal cases.
Article
We assessed the diagnostic accuracy of multislice CT in detection of intracranial aneurysms in patients presenting with subarachnoid or intracranial haemorrhage. Multislice CT and multiplanar digital subtraction angiography (DSA) images were obtained in 50 consecutive patients presenting with subarachnoid (SAH) and/or intracranial haemorrhage and reviewed by three neuroradiologists for the number, size and site of any aneurysms. The CT data were assessed using multiplanar reformats (MPR), maximum-intensity projections (MIP), surface-shaded display (SSD) and volume-rendering (VRT). In conventional angiography 51 aneurysms were detected in 41 patients. CT angiography (CTA) showed up to 48 aneurysms in 39 patients, depending on the observer. The overall sensitivity of multislice CT was 83.3% for small (< 4 mm), 90.6% for medium-size (5-12 mm) and 100% for large (> 13 mm) aneurysms. The sensitivity of multislice CTA to medium-size and large intracranial aneurysm is within the upper part of the range reported for helical single-slice CT. However, as small aneurysms may not be found, DSA remains the standard technique for investigation of SAH.
Article
Computed tomographic (CT) angiography is a well-known tool for detection of intracranial aneurysms and the planning of therapeutic intervention. Despite a wealth of existing studies and an increase in image quality due to use of multisection CT and increasingly sophisticated postprocessing tools such as direct volume rendering, CT angiography has still not replaced digital subtraction angiography as the standard of reference for detection of intracranial aneurysms. One reason may be that CT angiography is still not a uniformly standardized method, particularly with regard to image postprocessing. Several methods for two- and three-dimensional visualization can be used: multiplanar reformation, maximum intensity projection, shaded surface display, and direct volume rendering. Pitfalls of CT angiography include lack of visibility of small arteries, difficulty differentiating the infundibular dilatation at the origin of an artery from an aneurysm, the kissing vessel artifact, demonstration of venous structures that can simulate aneurysms, inability to identify thrombosis and calcification on three-dimensional images, and beam hardening artifacts produced by aneurysm clips. Finally, an algorithm for the safe and useful application of CT angiography in patients with subarachnoid hemorrhage has been developed, which takes into account the varying quality of equipment and software at different imaging centers.
Article
The aim of this study was to assess the usefulness of 16-row multislice CT angiography (CTA) in evaluating intracranial aneurysms, by comparison with conventional digital subtraction angiography (DSA) and intraoperative findings. A consecutive series of 57 patients, scheduled for DSA for suspected intracranial aneurysm, was prospectively recruited to have CTA. This was performed with a 16-detector row machine, detector interval 0.75 mm, 0.5 rotation/s, table speed 10mm/rotation and reconstruction interval 0.40 mm. CTA studies were independently and randomly assessed by two neuroradiologists and a vascular neurosurgeon blinded to the DSA and surgical findings. Review of CTA was performed on workstations with an interactive 3D volume-rendered algorithm. DSA or intraoperative findings or both confirmed 53 aneurysms in 44 patients. For both independent readers, sensitivity and specificity per aneurysm of DSA were 96.2% and 100%, respectively. Sensitivity and specificity of CTA were also 96.2% and 100%, respectively. Mean diameter of aneurysms was 6.3mm (range 1.9 to 28.1 mm, SD 5.2 mm). For aneurysms of less than 3 mm, CTA had a sensitivity of 91.7% for each reader. Although the neurosurgeon would have been happy to proceed to surgery on the basis of CTA alone in all cases, he judged that DSA might have provided helpful additional anatomical information in 5 patients. The diagnostic accuracy of 16-slice CTA is promising and appears equivalent to that of DSA for detection and evaluation of intracranial aneurysms. A strategy of using CTA as the primary imaging method, with DSA reserved for cases of uncertainty, appears to be practical and safe.
Article
To evaluate the clinical role of CT angiography (CTA) in patients with acute subarachnoid hemorrhage (SAH) for treatment decision-making. Consecutive patients with acute SAH had CTA using a 64-slice scanner for initial clinical decision-making. Image processing included multiplanar volume reformatted (MPVR) maximum intensity projections (MIP) and 3D volume-rendered reconstructions. CTAs were used for (1) evaluating the cause of SAH, and (2) triaging aneurysm-bearing patients to the more appropriate management, either surgical clipping or endovascular coiling. CTA findings were confirmed by neurosurgical exploration or catheter angiography (digital subtraction angiography, DSA). Successful coiling provided evidence that triaging to endovascular treatment was correct. Included in the study were 73 patients. CTA findings were confirmed by DSA or neurosurgical operation in 65 patients, and of these 65, 47 had aneurysmal SAH, 3 had vasculitis, 1 had arterial dissection and 14 had no underlying arterial abnormality. The cause of SAH was detected with CTA in 62 out of the 65 patients (95.4%, sensitivity 94%, specificity 100%). CTA revealed the aneurysm in 46 of 47 patients (98%, sensitivity 98%, specificity 100%, positive predictive value 100%, negative predictive value 82.3%), 1 of 3 vasculitides and 1 of 1 dissection. Of the 46 patients with aneurysm, 44 (95.7%) were referred for treatment based on CTA. In 2 patients (2 of 46, 4.4%) CTA was not informative enough to choose treatment requiring DSA. Of the 44 patients, 27 (61.4%) were referred to endovascular treatment and successful coiling was achieved in 25 (25 of 27, 92.6%). CTA using a 64-slice scanner is an accurate tool for detecting and characterizing aneurysms in acute SAH. CTA is useful in the decision process whether to coil or clip an aneurysm.
Article
The clinical significance of sentinel headaches in patients with subarachnoid hemorrhage (SAH) is still unknown. We investigated whether patients with a sentinel headache (SH) have a higher rate of rebleeding after SAH. An SH was defined as a sudden, severe, unknown headache lasting >1 hour with or without accompanying symptoms, not leading to a diagnosis of SAH in the 4 weeks before the index SAH. Age, sex, smoking status, clinical grade, computed tomography (CT) findings, angiographic findings, placement of an external ventricular drain, and time to aneurysm obliteration were prospectively recorded. All rebleeding events were confirmed by CT. Outcome was assessed at 6 months according to the modified Rankin Scale. Of 237 consecutive patients with SAH, 41 (17.3%) had an SH. Rebleeding occurred in 23 (9.7%) of all patients. Patients with an SH had a 10-fold increased odds of rebleeding compared with patients without SH. Aneurysm size and the total number of aneurysms were also significantly associated with rebleeding. There were no differences in age, sex, smoking, CT or angiographic findings, external ventricular drain placement, or time to aneurysm obliteration between groups. Patients with rebeeding had a significantly worse outcome. Logistic regression revealed the presence of an SH as an independent risk factor for rebleeding. In our study, patients with SAH who had an SH constituted a special group of patients with a 10-fold odds for early rebleeding. The presence of an SH may select candidates for ultraearly aneurysm obliteration or drug treatment.
Article
Purpose: Contrast-induced acute kidney injury or contrast-induced nephropathy (CIN) is a significant complication of intravascular contrast medium (CM). These guidelines are intended as a practical approach to risk stratification and prevention. The major risk factor that predicts CIN is pre-existing chronic kidney disease. Methods: Members of the committee represent radiologists and nephrologists across Canada. The previous guidelines were reviewed, and an in-depth up-to-date literature review was carried out. Results: A serum creatinine level (SCr) should be obtained, and an estimated glomerular filtration rate (eGFR) should be calculated within 6 months in the outpatient who is stable and within 1 week for inpatients and patients who are not stable. Patients with an eGFR of ≥ 60 mL/min have an extremely low risk of CIN. The risk of CIN after intra-arterial CM administration appears be at least twice that after intravenous administration. Fluid volume loading remains the single most important measure, and hydration regimens that use sodium bicarbonate or normal saline solution should be considered for all patients with GFR < 60 mL/min who receive intra-arterial contrast and when GFR < 45 mL/min in patients who receive intravenous contrast. Patients are most at risk for CIN when eGFR < 30 mL/min. Additional preventative measures include the following: avoid dehydration, avoid CM when appropriate, minimize CM volume and frequency, avoid high osmolar CM, and discontinue nephrotoxic medications 48 hours before administration of CM.
Article
The aim of this study was to determine the accuracy of multi-detector row computed tomography angiography (CTA) for the triage of patients with acutely ruptured aneurysms, and to assess how therapeutic decisions based on this method compared with digital subtraction angiography (DSA). Twenty-seven consecutive patients with acute subarachnoid hemorrhage were included, and underwent both CTA and DSA. CTA was performed on a 16-detector row CT scanner with a 0.75-mm collimation and a 0.558-beam pitch. Two readers reviewed the CTA data, and two different readers reviewed the DSA data. Aneurysm characteristics were recorded and treatment by surgical clipping or endovascular coil embolization was proposed. A total of 24 aneurysms were identified on DSA in 21 patients. Sensitivity and specificity for CTA were 100% and 83%, respectively, on a per-aneurysm-basis. The correlation between DSA and CTA for the determination of sac and neck sizes was very good (r=0.92, and r=0.95, respectively, P<0.0001). Sensitivity and specificity for the detection of arterial branches incorporated into the aneurysmal sac or neck were 50% and 100%, respectively. In three aneurysms, readers judged CTA inappropriate for triage, because peri-aneurysmal branches were not properly visualized. Overall agreement between CTA and DSA regarding the therapeutic decision between surgical clipping and endovascular coil embolization in 24 aneurysms was good (kappa=0.76). Multi-detector row CTA provides accurate anatomic information for aneurysm location as well as sac and neck sizes; however, the technique appears to have a low sensitivity in detecting branches incorporated into the aneurysmal sac.
Article
To evaluate the utility of computed tomographic angiography (CTA) as the primary diagnostic investigation in patients with spontaneous subarachnoid hemorrhage (SAH), and to correlate the results with intraoperative findings in those with ruptured aneurysms. A retrospective review of 243 patients with spontaneous SAH was performed. The patients selected were those with acute SAH confirmed by noncontrast head computed tomography or by cerebrospinal fluid findings from a lumbar puncture. Patients subsequently underwent preoperative three-dimensional CTA as the sole or primary diagnostic study. The results of the CTA were correlated with the intraoperative findings in those patients undergoing emergent surgical clipping of acutely ruptured intracranial aneurysms. CTA correctly detected the ruptured aneurysm in 170 of the 171 cases, which required surgical clipping. Our data demonstrates that CTA has a 99.4% detection rate in acutely ruptured aneurysms as compared to intraoperative findings [confidence interval 97.8-99.9%]. CTA can provide prompt and accurate diagnostic and anatomic information in the setting of SAH with an excellent detection rate in acute ruptured aneurysms. These findings suggest an increased role for CTA in the evaluation of cerebral aneurysms.
Article
Computed tomography (CT) and CT angiography (CTA) are frequently the initial imaging modalities used in the evaluation of patients with suspected aneurysmal subarachnoid hemorrhage (SAH). It remains unclear whether CTA can provide adequate information to determine best treatment modality (endovascular versus surgical) for ruptured intracranial aneurysms. Pertinent clinical and radiological information of consecutive patients with aneurysmal SAH who underwent CTA on a 64-slice multidetector CT (MDCT) scanner were independently reviewed by five endovascular specialists. Subsequently, the interobserver reliability was calculated. A total of 21 consecutive patients with aneurysmal SAH detected on CTA were reviewed. Of the total of 105 reviews, in 65% a treatment allocation decision was made. Responses were, 26% either treatment; 18% endovascular only; 18% surgical only; and 3% neither treatment. In the remaining 35% it was considered that CTA images were inadequate to make a decision for treatment allocation and more information was requested. Interobserver reliability was poor between endovascular specialists (k = 0.2). The reliability was higher among endovascular/vascular neurosurgeons (k = 0.34) and physicians with >5 years of faculty experience (k = 0.55). When 64-slice MDCT angiography is used in the evaluation of aneurysmal SAH, the information obtained is adequate to determine treatment modality allocation in two-thirds of the cases. The agreement on best treatment modality varied across primary specialty, practice experience, and site of fellowship completion.