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Conventional CT scan one day before and one month after shunt surgery. Representative cases diagnosed with adult-onset congenital NPH (A,B), secondary NPH (C,D) and idiopathic NPH (E,F).
Source publication
The present study aimed to examine time-dependent change in cerebrospinal fluid distribution and various radiological indices for evaluating shunt effectiveness in patients with idiopathic normal pressure hydrocephalus (iNPH). This study included 54 patients with iNPH who underwent MRI before and after ventriculoperitoneal shunt surgery. The volume...
Contexts in source publication
Context 1
... (Fig. 1A-D) 16,17 . However, the ventricular size measured by the Evans index remains often unchanged in elderly patients with iNPH ( Fig. 1E,F), even if their symptoms are improved after shunting [18][19][20][21] . The key features of iNPH are compressed high-convexity sulci concurrent with enlarged Sylvian fissure and basal cistern, i.e., ...
Context 2
... However, the ventricular size measured by the Evans index remains often unchanged in elderly patients with iNPH ( Fig. 1E,F), even if their symptoms are improved after shunting [18][19][20][21] . The key features of iNPH are compressed high-convexity sulci concurrent with enlarged Sylvian fissure and basal cistern, i.e., disproportionately enlarged subarachnoid space hydrocephalus (DESH) 4,22-24 . We recently showed that the pathophysiological mechanism of ...
Similar publications
Background
Maintenance of pressure gradient within the intracranial chamber, shunt hardware, and the abdominal cavity plays a significant role in the optimal functioning of the ventriculo peritoneal shunt. We report a rare and a complex scenario in a patient with normal pressure hydrocephalus (NPH) who had recurrent and refractory ventricular perit...
Citations
... On the other hand, it is shown that ventricular enlargement is predominantly on the z-axis rather than the x-axis in iNPH patients [12]. A study performed by Yamada et al. showed that expansion of the lateral ventricles in the z-axis is a common parameter to distinguish NPH from Alzheimer's disease [13]. In our study, EI had poor diagnostic performance in the detection of iNPH in patients with ventriculomegaly. ...
Purpose
Idiopathic normal-pressure hydrocephalus (iNPH) presents with Hakim’s triad and diagnosis is solely based on clinical findings. The role of imaging is confined to the detection of ventriculomegaly and the exclusion of other possible entities. Hyperdynamic CSF flow has been demonstrated in various flow-related imaging studies. In this study, we aimed to investigate the diagnostic performance of the “black tent” sign in the CSF flow-sensitive T2 SPACE sequence.
Materials and methods
This retrospective study includes 22 patients diagnosed with iNPH who underwent CSF shunting and benefited from the procedure and showed clinical recovery. The control group consisted of 38 patients with excluded diagnoses of iNPH by clinical examination and follow-up. T2 SPACE images from both groups were assessed according to the presence of the “black tent” which was defined as a signal void detected on the T2 SPACE image traced along the borders of the fourth ventricle and filling the triangular area of the median dorsal recess. The diagnostic performance of the sign was calculated, and the results were compared with those of Evan’s Index, callosal angle, and disproportionately enlarged subarachnoid spaces.
Results
The diagnostic performance of the black tent sign in diagnosing iNPH was determined with a sensitivity of 90.91%, specificity of 78.95%, PPV of 71.43%, NPV of 93.75%, and overall accuracy of 83.33%. The sign showed better diagnostic performance in participants over 60 years in which sensitivity, specificity, PPV, NPV, and accuracy increased to 86.67%, 93.75%, 86.67%, 99.75%, and 91.49% respectively. Diagnostic performance of the sign was superior to DESH ( p = 0.007).
Conclusion
The black tent sign observed in T2 SPACE images in CSF flow MRI studies correlates with the diagnosis of iNPH with high sensitivity and specificity.
... 19,20 Research on NPH has validated the importance of MEI and CPCA as diagnostic tools, and our findings confirm MEI and CPCA as key diagnostic biomarkers for adult non-NPH. [21][22][23] Although NPH and non-NPH share some radiologic markers, their clinical presentations and underlying pathophysiology differ, necessitating careful interpretation within each context. Regarding the bicaudate index, while it was among the top 10 important parameters, our study found it was not a key biomarker for diagnosing non-NPH, in accordance with Zuurbier et al. 24 In general, the differences between the results of previous studies and our findings may stem from the methodologies used. ...
BACKGROUND AND OBJECTIVES
Hydrocephalus involves abnormal cerebrospinal fluid accumulation in brain ventricles. Early and accurate diagnosis is crucial for timely intervention and preventing progressive neurological deterioration. The aim of this study was to identify key neuroimaging biomarkers for the diagnosis of hydrocephalus using artificial intelligence to develop practical and accurate diagnostic tools for neurosurgeons.
METHODS
Fifteen 1-dimensional (1-D) neuroimaging parameters and ventricular volume of adult patients with non-normal pressure hydrocephalus and healthy subjects were measured using manual image processing, and 10 morphometric indices were also calculated. The data set was analyzed using 8 machine, ensemble, and deep learning classifiers to predict hydrocephalus. SHapley Additive exPlanations (SHAP) feature importance analysis identified key neuroimaging diagnostic biomarkers.
RESULTS
Gradient Boosting achieved the highest performance, with an accuracy of 0.94 and an area under the curve of 0.97. SHAP analysis identified ventricular volume as the most important parameter. Given the challenges of measuring volume for clinicians, we identified key 1-D morphometric biomarkers that are easily measurable yet provide similar classifier performance. The results showed that the frontal-temporal horn ratio, modified Evan index, modified cella media index, sagittal maximum lateral ventricle height, and coronal posterior callosal angle are key 1-D diagnostic biomarkers. Notably, higher modified Evan index, modified cella media index, and sagittal maximum lateral ventricle height, and lower frontal-temporal horn ratio and coronal posterior callosal angle values were associated with hydrocephalus prediction. The results also elucidated the relationships between these key 1-D morphometric parameters and ventricular volume, providing potential diagnostic insights.
CONCLUSION
This study highlights the importance of a multifaceted diagnostic approach incorporating 5 easily measurable 1-D neuroimaging biomarkers for neurosurgeons to differentiate non-normal pressure hydrocephalus from healthy subjects. Incorporating our artificial intelligence model, interpreted through SHAP analysis, into routine clinical workflows may transform the diagnostic landscape for hydrocephalus by standardizing diagnosis and overcoming the limitations of visual evaluations, particularly in early stages and challenging cases.
... The authors suggested that this decline reflects stagnant CSF flow due to simultaneous ventricle and lateral sulci expansion toward the cranial apex, potentially indicative of glymphatic dysfunction affecting downstream paravascular flow. 39,[153][154][155][156] In summary, these investigations collectively suggest that IVIM metrics, notably f, offer valuable insights for assessing complex CSF motion in ventricles and subarachnoid spaces. While the pseudodiffusion coefficient, D*, theoretically provides the most direct assessment of flow velocity, it exhibits less robustness during the bi-exponential model fitting. ...
Cerebrospinal fluid (CSF) plays a critical role in metabolic waste clearance from the brain, requiring its circulation throughout various brain pathways, including the ventricular system, subarachnoid spaces, para‐arterial spaces, interstitial spaces, and para‐venous spaces. The complexity of CSF circulation has posed a challenge in obtaining noninvasive measurements of CSF dynamics. The assessment of CSF dynamics throughout its various circulatory pathways is possible using diffusion magnetic resonance imaging (MRI) with optimized sensitivity to incoherent water movement across the brain. This review presents an overview of both established and emerging diffusion MRI techniques designed to measure CSF dynamics and their potential clinical applications. The discussion offers insights into the optimization of diffusion MRI acquisition parameters to enhance the sensitivity and specificity of diffusion metrics on underlying CSF dynamics. Lastly, we emphasize the importance of cautious interpretations of diffusion‐based imaging, especially when differentiating between tissue‐ and fluid‐related changes or elucidating structural versus functional alterations.
... From our previous study using 3D T2-weighted MRI data acquired on MAGNETOM Skyra (Siemens AG, Munich, Germany) until September 2019 (Yamada et al., 2015(Yamada et al., , 2016a(Yamada et al., ,b, 2017b(Yamada et al., , 2019, 14 patients (10 Hakim patients and 4 volunteers) were included in this study. Subsequently, from our recent study (Yamada et al., 2020(Yamada et al., , 2021c(Yamada et al., , 2023a, 115 patients (26 Hakim patients and 89 volunteers) who had undergone 3D T1-weighted and T2-weighted MRIs on a Discovery MR 750 W (GE Healthcare, Milwaukee, Wisconsin, United States) from October 2019 to January 2022, and 51 participants (6 Hakim patients and 45 volunteers) on a Signa Architect 3.0 T (GE Healthcare) from February 2022 to May 2022 were enrolled in this study. ...
Background
Disproportionately enlarged subarachnoid-space hydrocephalus (DESH) is a key feature for Hakim disease (idiopathic normal pressure hydrocephalus: iNPH), but subjectively evaluated. To develop automatic quantitative assessment of DESH with automatic segmentation using combined deep learning models.
Methods
This study included 180 participants (42 Hakim patients, 138 healthy volunteers; 78 males, 102 females). Overall, 159 three-dimensional (3D) T1-weighted and 180 T2-weighted MRIs were included. As a semantic segmentation, 3D MRIs were automatically segmented in the total ventricles, total subarachnoid space (SAS), high-convexity SAS, and Sylvian fissure and basal cistern on the 3D U-Net model. As an image classification, DESH, ventricular dilatation (VD), tightened sulci in the high convexities (THC), and Sylvian fissure dilatation (SFD) were automatically assessed on the multimodal convolutional neural network (CNN) model. For both deep learning models, 110 T1- and 130 T2-weighted MRIs were used for training, 30 T1- and 30 T2-weighted MRIs for internal validation, and the remaining 19 T1- and 20 T2-weighted MRIs for external validation. Dice score was calculated as (overlapping area) × 2/total area.
Results
Automatic region extraction from 3D T1- and T2-weighted MRI was accurate for the total ventricles (mean Dice scores: 0.85 and 0.83), Sylvian fissure and basal cistern (0.70 and 0.69), and high-convexity SAS (0.68 and 0.60), respectively. Automatic determination of DESH, VD, THC, and SFD from the segmented regions on the multimodal CNN model was sufficiently reliable; all of the mean softmax probability scores were exceeded by 0.95. All of the areas under the receiver-operating characteristic curves of the DESH, Venthi, and Sylhi indexes calculated by the segmented regions for detecting DESH were exceeded by 0.97.
Conclusion
Using 3D U-Net and a multimodal CNN, DESH was automatically detected with automatically segmented regions from 3D MRIs. Our developed diagnostic support tool can improve the precision of Hakim disease (iNPH) diagnosis.
... In case there is a shunt failure, the PL change will have no effect and pose no risk. The rate of change in VV at the first follow-up after surgery in this study (−8%) was smaller when compared with previously published results ranging from −12.1% to 26.1% in the lateral 11,13,14 or first three ventricles. [15][16][17] This difference could reflect the shorter interval between surgery and follow-up MRI of 1 month in this study compared to the range of 1-12 months in the previous work, but could also reflect the use of different shunt valves and shunt settings. ...
OBJECTIVE
MRI volumetry could be used as an alternative to invasive tests of shunt function. In this study, the authors aimed to assess the difference in ventricular volume (VV) before and after surgery and at different performance levels (PLs) of the shunt.
METHODS
This study was a randomized, double-blind trial with a crossover design. The study sample consisted of 36 patients (25 men, 11 women) with a median age of 76 years. All patients had idiopathic normal pressure hydrocephalus (iNPH) and received a Strata shunt at the regional hospital in Östersund, Sweden, with an initial PL of 1.5. Participants underwent MRI with volumetric sequences before surgery and four times postoperatively: at 1 month before randomization to either PL 1.0 (n = 15) or 2.5 (n = 17); at 2 months before crossover to PL 2.5 or 1.0; at 3 months before lowering the PL to 0.5; and finally, at 3 months and 1 day after surgery before resetting the PL to 1.5. VV was measured semiautomatically using quantitative MRI. Both the patient and the examiner of clinical tests and volumetry were blinded to the PL.
RESULTS
VV changed significantly between the presurgical level (median 129 ml) and the different shunt settings, i.e., PL 1.0 (median 115 ml), 1.5 (median 120 ml), and 2.5 (median 128 ml; p < 0.001). A unidirectional change in VV was observed for all participants between PL 1.0 and PL 2.5 (median 12 ml, range 2.1–40.7 ml, p < 0.001). No significant change was noted in VV after 24 hours at PL 0.5. Eight participants had asymptomatic subdural effusions at PL 1.0.
CONCLUSIONS
The consistent decrease in VV after shunt surgery and between PL 2.5 and 1.0 supports the idea that MRI volumetry could be a noninvasive method for evaluating shunt function in iNPH, preventing unnecessary shunt revisions. However, further studies on retest variability of VV as well as verification against advanced testing of shunt function are needed before a clinical implementation of this method can be performed.
Clinical trial registration no.: NCT04599153 ( ClinicalTrials.gov )
... However, post VP shunt implementation follow-ups are mostly consisted of clinical reviews that rely on observable signs and symptoms by neurologists Williams M, et al. (2016) [2]. In some conditions though ventricle dilation and cortical atrophy extension may address the demand for VP shut to be re-programed [3]. The presenting case outlines difficulties in evaluating the functionality of the VP shunt for an NPH patient. ...
... Panels (A,C,D) reprinted with kind permission from Springer Science and Business Media from Streitberger et al. (2012). Panel (B) reprinted with kind permission from Nature Portfolio from Yamada et al. (2019). subsequent development of neurodegenerative disorders after TBI (Donat et al., 2017). ...
Cells are continuously exposed to physical forces and the central nervous system (CNS) is no exception. Cells dynamically adapt their behavior and remodel the surrounding environment in response to forces. The importance of mechanotransduction in the CNS is illustrated by exploring its role in CNS pathology development and progression. The crosstalk between the biochemical and biophysical components of the extracellular matrix (ECM) are here described, considering the recent explosion of literature demonstrating the powerful influence of biophysical stimuli like density, rigidity and geometry of the ECM on cell behavior. This review aims at integrating mechanical properties into our understanding of the molecular basis of CNS disease. The mechanisms that mediate mechanotransduction events, like integrin, Rho/ROCK and matrix metalloproteinases signaling pathways are revised. Analysis of CNS pathologies in this context has revealed that a wide range of neurological diseases share as hallmarks alterations of the tissue mechanical properties. Therefore, it is our belief that the understanding of CNS mechanotransduction pathways may lead to the development of improved medical devices and diagnostic methods as well as new therapeutic targets and strategies for CNS repair.
... Studies have shown that the VV of patients with NPH decreases after surgery. However, even if the clinical symptoms of NPH patients improve after surgery, the EI remains unchanged even during the entire follow-up process after surgery (Yamada et al., 2019). The clinical improvement in NPH patients after surgery is related to a decrease in ventricle size. ...
... Subsequent studies have shown that the expansion of the lateral ventricle toward the z-axis (z-EI) is a common parameter for distinguishing NPH from AD (Yamada et al., 2016). More importantly, in the followup process of NPH patients after surgery, the z-EI continued to change gradually changing, while the EI did not change (Yamada et al., 2019). Therefore, in the 2021 NPH guidelines, even an EI <0.30, in case of the presence of other indicators of an expanded inferior horn of the lateral ventricle, such as a z-EI >0.42, the diagnosis of possible NPH is acceptable (Nakajima et al., 2021). ...
With an ever-growing aging population, the prevalence of normal pressure hydrocephalus (NPH) is increasing. Clinical symptoms of NPH include cognitive impairment, gait disturbance, and urinary incontinence. Surgery can improve symptoms, which leads to the disease's alternative name: treatable dementia. The Evans index (EI), defined as the ratio of the maximal width of the frontal horns to the maximum inner skull diameter, is the most commonly used index to indirectly assess the condition of the ventricles in NPH patients. EI measurement is simple, fast, and does not require any special software; in clinical practice, an EI >0.3 is the criterion for ventricular enlargement. However, EI's measurement methods, threshold setting, correlation with ventricle volume, and even its clinical value has been questioned. Based on the EI, the z-EI and anteroposterior diameter of the lateral ventricle index were derived and are discussed in this review.
... This morphological characteristic of CSF distribution specific to iNPH has been called as Disproportionately Enlarged Subarachnoid-Space Hydrocephalus (DESH) (49,50). As quantitative indicators of DESH, the callosal angle defined as the angle of the roof of the bilateral ventricles on the coronal plane at the posterior commissure (PC) level (51) and brain per ventricle ratios (BVRs) defined as the maximum width of the brain just above the lateral ventricles divided by the maximum width of the lateral ventricles on the coronal planes at the at the anterior commissure (AC) and PC levels (52) are useful not only for preoperative evaluation but also for comparison before and after shunt surgery (53,54). ...
... Compared to secondary NPH subsequent to subarachnoid hemorrhage (77), iNPH may have a longer period from CSF accumulation to the appearance of symptoms (45). It may take some time for normal CSF distribution and brain formation to return (54). Based on this evidence, if the expected improvement in symptoms and radiological findings are not observed 6 months after shunting, the shunt valve pressure should be reduced one level from the initial optimal valve pressure 6 months to 1 year after shunting (Figure 6). ...
Treatment for idiopathic normal pressure hydrocephalus (iNPH) continues to develop. Although ventriculoperitoneal shunt surgery has a long history and is one of the most established neurosurgeries, in the 1970s, the improvement rate of iNPH triad symptoms was poor and the risks related to shunt implantation were high. This led experts to question the surgical indication for iNPH and, over the next 20 years, cerebrospinal fluid (CSF) shunt surgery for iNPH fell out of favor and was rarely performed. However, the development of programmable-pressure shunt valve devices has reduced the major complications associated with the CSF drainage volume and appears to have increased shunt effectiveness. In addition, the development of support devices for the placement of ventricular catheters including preoperative virtual simulation and navigation systems has increased the certainty of ventriculoperitoneal shunt surgery. Secure shunt implantation is the most important prognostic indicator, but ensuring optimal initial valve pressure is also important. Since over-drainage is most likely to occur in the month after shunting, it is generally believed that a high initial setting of shunt valve pressure is the safest option. However, this does not always result in sufficient improvement of the symptoms in the early period after shunting. In fact, evidence suggests that setting the optimal valve pressure early after shunting may cause symptoms to improve earlier. This leads to improved quality of life and better long-term independent living expectations. However, in iNPH patients, the remaining symptoms may worsen again after several years, even when there is initial improvement due to setting the optimal valve pressure early after shunting. Because of the possibility of insufficient CSF drainage, the valve pressure should be reduced by one step (2–4 cmH2O) after 6 months to a year after shunting to maximize symptom improvement. After the valve pressure is reduced, a head CT scan is advised a month later.
... Due to abnormal CSF circulation, the lateral ventricle and the Sylvian fissure dilate, and the latter resists the pressure of lateral ventricle dilation, so the ventricle dilates mainly along the Z-axis (which is perpendicular to the bi-commissural line). We hypothesize that the white matter in the CS is subjected to externally induced mechanical stress first (Silverberg et al., 2015;Yamada et al., 2019;Younes et al., 2019). As the disease progresses, prolonged compression of the white matter fibers leads to interstitial edema and progressive axonal loss (Younes et al., 2019), resulting in a decrease in the FA value and an increase in the ADC value. ...
The study preliminarily explored the sequence and difference of involvement in different neuroanatomical structures in idiopathic normal pressure hydrocephalus (INPH). We retrospectively analyzed the differences in diffusion tensor imaging (DTI) parameters in 15 ROIs [including the bilateral centrum semiovale (CS), corpus callosum (CC) (body, genu, and splenium), head of the caudate nucleus (CN), internal capsule (IC) (anterior and posterior limb), thalamus (TH), and the bilateral frontal horn white matter hyperintensity (FHWMH)] between 27 INPH patients and 11 healthy controls and the correlation between DTI indices and clinical symptoms, as evaluated by the INPH grading scale (INPHGS), the Mini-Mental State Examination (MMSE), and the timed up and go test (TUG-t), before and 1 month after shunt surgery. Significant differences were observed in DTI parameters from the CS (pFA1 = 0.004, pADC1 = 0.005) and the genu (pFA2 = 0.022; pADC2 = 0.001) and body (pFA3 = 0.003; pADC3 = 0.002) of the CC between the groups. The DTI parameters from the CS were strongly correlated with the MMSE score both pre-operatively and post-operatively. There was association between apparent diffusion coefficient (ADC) values of anterior and posterior limbs of the IC and MMSE. The DTI parameters of the head of the CN were correlated with motion, and the ADC value was significantly associated with the MMSE score. The FA value from TH correlated with an improvement in urination after shunt surgery. We considered that different neuroanatomical structures are affected differently by disease due to their positions in neural pathways and characteristics, which is further reflected in clinical symptoms and the prognosis of shunt surgery.
