Objectives Frailty, reflecting reduced physiological reserve and increased vulnerability to stressors, is common among patients with idiopathic normal pressure hydrocephalus (iNPH). The extent to which frailty influences gait outcomes following ventriculoperitoneal shunting (VPS) remains unclear. This study evaluated the association between frailty and objective gait changes after VPS in patients with iNPH. Methods A single-center database was reviewed for patients who underwent VPS for iNPH with preoperative gait analysis between October 2018 and May 2024. Gait parameters included cadence, velocity, stability ratio, step width, stride length, single and total support. Patients were stratified by the modified 5-item frailty index (mFI) into non-frail (mFI-0), pre-frail (mFI-1), and frail (mFI-2+). Generalized additive mixed-effects models evaluated time, mFI, and their interaction with patient-specific random effects. Results Of the 242 patients that were included, 60 (24.8%) were classified preoperatively as non-frail, 109 (45%) were pre-frail, and 73 (30.2%) were frail, with no difference in age distributions across groups. A total of 844 gait analyses were performed with a median of three per patient and a median latest follow-up time of 12.2 months. Preoperative gait parameters varied significantly across mFI groups. However, the degree of change in gait parameters between preoperative and first postoperative gait assessments did not differ across mFI groups, with most patients exhibiting improvement. Conclusion Frailty correlated with worse baseline gait performance but did not diminish the likelihood or durability of gait improvement following VPS. These findings suggest that VPS yields meaningful gait benefits in patients with iNPH regardless of frailty status.

[This corrects the article DOI: 10.1212/NE9.0000000000200169.].

Conebeam CT (CBCT) is an imaging technique that provides high-resolution, cross-sectional imaging in the fluoroscopy suite. In neuroradiology, CBCT has been used for various applications including temporal bone imaging and during spinal and cerebral angiography. Furthermore, CBCT has been shown to improve imaging of spinal CSF leaks during myelography. One drawback of CBCT is that images have a relatively high noise level. In this technical report, we describe the first application of a high-resolution convolutional neural network to denoise conebeam CT myelographic images. We show examples of the resulting improvement in image quality for a variety of types of spinal CSF leaks. Further application of this technique is warranted to demonstrate its clinical utility and potential use for other CBCT applications.

CSF-venous fistulas (CVFs) are a common cause of spontaneous intracranial hypotension. Due to the more routine use of decubitus myelography and advancements in various imaging techniques, recognition of CVFs has increased in recent years. Most commonly, patients harbor only 1 fistula at the time of myelography (although additional de novo fistulas can arise after treatment). Occasionally, 2 synchronous CVFs may be seen on a single myelogram. The coexistence of more than 2 CVFs, however, is quite rare and has only been previously described in 2 instances. Here, we present a multi-institutional series of 16 patients with 3 or more concurrently discovered CVFs, representing the largest cohort of such patients to date. We describe their clinical features, imaging findings, treatment approaches, and outcomes.

BACKGROUND:CSF-venous fistulas (CVFs) are an important and underrecognized cause of spontaneous intracranial hypotension. Accurate localization is essential for effective treatment. However, data regarding which areas of the spine are at higher risk are limited. PURPOSE:To evaluate the prevalence of affected laterality and spinal levels in patients with CVFs. DATA SOURCES:Scopus, Web of Science, Embase, and PubMed databases. STUDY SELECTION:Studies involving 3 or more patients with confirmed CVFs that specified the level and side of involvement were included. When multiple studies originated from the same institution or research group, they were further reviewed and narrowed to avoid data overlap, prioritizing inclusion of the largest studies. DATA ANALYSIS:Meta-analysis of demographic characteristics, side of involvement, and spinal levels of CVFs. Pooled prevalence rates were computed, and age and gender distribution across studies were analyzed. Pair-wise meta-regression was used, and laterality was further assessed at each spinal level to determine the distribution of right-versus left-sided leaks. Heterogeneity was assessed using Q statistics and the I2 test, with significance defined as an I2 value >50% or a P value <.05. DATA SYNTHESIS:Thirty-six observational studies consisting of 1145 patients (63% women) were analyzed. Most CVFs involved the lower portion of the thoracic spine, including T7 (28/180; 19%; 95% CI: 0.13-0.28), T9 (33/238; 19%; 95% CI: 0.13-0.30), and T10 (31/190; 17%; 95% CI: 0.13-0.24). More CVFs occurred on the right side of the spine (394/709; 67%; 95% CI: 0.62-0.73; P <.001) when compared to the left (214/786; 31%; 95% CI: 0.24-0.39) and bilaterally (18/313; 8%; 95% CI: 0.04-0.18). LIMITATIONS:Study limited by retrospective approach, reporting bias, and paucity of large published series of patients with CVFs. Furthermore, reporting was not standardized, making statistical comparison difficult. CONCLUSIONS:In patients with CVFs, the thoracic spine appears to be the most heavily involved region, especially on the right side.

BACKGROUND AND OBJECTIVES:Ventriculoperitoneal shunt (VPS) placement is a common treatment for idiopathic normal pressure hydrocephalus (iNPH), but patients may require VPS revision. This study aims to evaluate the effectiveness of a standardized VPS placement protocol by comparing indications and rates of shunt revision compared with a historical institutional cohort. METHODS:All patients treated with VPS for "suspected" iNPH at a tertiary care center between January 2000 and January 2023 were retrospectively reviewed and divided into temporally distinct historical (before 2017) and standardized (after 2017) cohorts. Cumulative incidence and timing of VPS revision were compared using competing risks analyses. RESULTS:A total of 561 patients (median age 75.0 years) were identified with 324 (57.8%) in the historical and 237 (42.2%) in the standardized cohorts. Significant variations in surgical technique and shunt hardware were noted between the cohorts. With a median follow-up of 11.4 months for historical and 12.4 months for standardized cohort, shunt revisions occurred in 19.4% and 8.4% of patients in the historical and standardized cohorts, respectively (P < .001). Revision indications also varied significantly with lower rates of overdrainage (P < .001), infection (P < .001), and proximal malfunction (P = .042) but higher rate of distal malfunction (P = .03) in the standardized cohort. Notably, no infections were noted in the standardized cohort. CONCLUSION:Risk of shunt revision among iNPH patients may be associated with modifiable factors related to surgical technique and shunt hardware selection. Importantly, no short-term complications such as hemorrhage, infection, or catheter malposition were observed with the standardized protocol. Development and refinement of standardized shunt protocols for iNPH patients should be commonplace to facilitate tracking, identification, and modification of modifiable technical risk factors.

CSF-venous fistulas are a common cause of spontaneous intracranial hypotension. Though these fistulas are increasingly recognized and diagnosed, their risk factors and pathogenesis remain incompletely understood. Previous studies have elucidated many nonheritable risk factors associated with CSF-venous fistulas, including elevated body mass index (BMI), presence of spinal degenerative changes, and advanced age. Furthermore, these fistulas are associated with the presence of spinal meningeal diverticula, though many asymptomatic patients also possess these diverticula. There are likely additional predisposing factors for this disease that are yet to be discovered. The existence of CSF-venous fistulas among closely related relatives has not been previously studied, even though such cases may imply a heritable basis for this disease. In this clinical report, we performed a retrospective, multicenter case series describing 4 pairs of first-degree relatives (8 patients) who developed CSF-venous fistulas. We evaluated the clinical and imaging features of these patients, finding that most had an elevated BMI and spinal meningeal diverticula. No patients had evidence of a connective tissue disorder. Overall, our study supports previous literature regarding nonheritable risk factors for CSF-venous fistulas but also suggests the presence of undiscovered genetic predispositions.

BACKGROUND AND PURPOSE:Idiopathic normal pressure hydrocephalus (iNPH) symptoms can be alleviated through shunt placement. However, the identification of suitable patients is often challenging despite several existing biomarkers. DTI is commonly used to assess white matter integrity, with DTI analysis along the perivascular space being a recently described though less extensively evaluated metric. It has been proposed to monitor glial-lymphatic (glymphatic) activity in the brain, the impairment of which may play a role in several neurologic diseases. The goal of this study is to evaluate the association of DTI along the perivascular space with other diffusion and structural imaging metrics among patients with normal pressure hydrocephalus and healthy controls to provide insight into the etiology of disease-related changes in the DTI along the perivascular space metric and the utility of this metric in disease diagnosis. MATERIALS AND METHODS:This study retrospectively identified 43 patients with iNPH and 86 sex- and age-matched controls. We compared the DTI along the perivascular space index, fractional anisotropy, ventricular volume, total intracranial volume, white matter hyperintensity volume, and perivascular space load between patients with iNPH and controls and evaluated the association of the DTI along the perivascular space index and other imaging metrics within each diagnostic group. RESULTS:We found that the DTI analysis along the perivascular space index and fractional anisotropy were significantly lower, and ventricular volume, total intracranial volume, white matter hyperintensity volume, and perivascular space load were significantly higher in patients with iNPH compared with controls. The ventricular volume, total intracranial volume, and white matter hyperintensity volume were correlated with the DTI analysis along the perivascular space index in the controls but not the patients with iNPH. CONCLUSIONS:A lower DTI analysis along the perivascular space index in patients with iNPH may be indicative of morphologic disease-related changes. The limited correlations with other imaging metrics suggest that the index is an independent or additive metric compared with existing structural or cerebrovascular disease markers of iNPH.

BACKGROUND AND PURPOSE: CSF-venous fistulas (CVFs) are a common cause of spontaneous intracranial hypotension. The diagnosis and precise localization of these fistulas hinges on specialized myelographic techniques, which mainly include decubitus digital subtraction myelography and decubitus CT myelography (by using either energy-integrating or photon-counting detector CT). A previous case series showed that conebeam CT myelography (CB-CTM), performed as an adjunctive tool with digital subtraction myelography, increased the detection of CVFs. Here, we sought to determine the additive yield of CB-CTM for CVF detection in a consecutive series of patients with spontaneous intracranial hypotension who underwent concurrent decubitus digital subtraction myelography and CB-CTM. MATERIALS AND METHODS: We retrospectively searched our institutional database for all consecutive patients who underwent decubitus digital subtraction myelography with adjunctive CB-CTM between August 5, 2021 and August 5, 2024. We excluded any patients harboring extradural CSF on spine imaging, not meeting International Classification of Headache Disorders, 3rd edition criteria for spontaneous intracranial hypotension, or not having undergone technically successful CB-CTM in combination with digital subtraction myelography. All myelographic images were independently reviewed by 2 neuroradiologists. We calculated the diagnostic yield of both myelographic tests for localizing a CVF. RESULTS: We identified 100 patients who underwent decubitus digital subtraction myelography with adjunctive conebeam CT. We excluded 15 patients based on above criteria. Fifty-nine of 85 patients had a single definitive CVF. Among positive cases, the fistula was visible on digital subtraction myelography in 38 of 59 patients and visible on CB-CTM in 59 of 59 patients. In 26 of 85 patients, no definitive fistula was identified by either technique. CONCLUSIONS: CB-CTM increased the diagnostic yield for CVF detection and may be a useful addition to digital subtraction myelography.

Post-dural puncture headache is an increasingly recognized cause of chronic headache. Outside of clinical history and myelography that requires an additional dural puncture, there is no reliable diagnostic test to evaluate for persistent dural defects. We describe the injection of iodinated contrast into the dorsal epidural space under CT guidance in 5 patients as a potential tool to visualize persistent dural defects.

Harlequin syndrome is a rare autonomic disorder characterized by unilateral facial flushing and contralateral anhidrosis. We sought to delineate underlying causes, clinical presentations, and autonomic testing profiles of patients with Harlequin syndrome. Retrospective chart review was performed of the Mayo Clinic electronic health record for patients with a Harlequin syndrome diagnosis from 1998 to 2024. Clinical, laboratory, imaging, and autonomic function testing results, including autonomic reflex screen (ARS) and thermoregulatory sweat test (TST), were reviewed. Of 51 patients with Harlequin syndrome, 39 (76

INTRODUCTION: While ventriculoperitoneal shunt (VPS) placement is increasingly considered standard of care for idiopathic normal pressure hydrocephalus (iNPH), many patients may require revision. This study aimed to identify independent predictors of shunt revision following VPS for iNPH. METHODS: All patient treated with shunting iNPH at a tertiary care center between January 2000 and January 2023 were retrospectively reviewed, and independent predictors of shunt revision were identified utilizing multivariable logistic regression. RESULTS: Of 574 total patients, 88 (15.3%) underwent revision (). Comparison between revised and non-revised patients disclosed associations of revision with age (73.2 ± 6.4 vs 75.0 ± 6.2 years; p = 0.02), prior shunt placement (2.3% vs 0.0%; p = 0.02), shunt type (ventriculoperitoneal: 94.3% vs 98.8%; ventriculoatrial: 5.7% vs 1.2%; p = 0.02), valve type (fixed: 63.6% vs 37.2%; programmable: 36.4% vs 62.8%; p < 0.01), distal catheter placement technique (open surgery: 71.1% vs 50.8%; laparoscopy: 28.9% vs 49.2%; p < 0.01), and proximal catheter placement approach (frontal: 61.4% vs 41.8%; occipital approach: 38.6% vs 58.2%, p < 0.01). Multivariable logistic regression showed that shunt revision was associated with younger age (OR=1.04/yr; p=0.02), ventriculopleural/ventriculoatrial placement (OR=4.48 [vs VPS]; p=0.02), fixed setting valve (OR=2.85 [versus adjustable]; p<0.01), open approach for distal catheter placement (OR=2.33 [versus laparoscopic]; p<0.01), frontal proximal catheter (OR=2.16 [versus parietal]; p<0.01), and ). Similar results were noted when analyzing predictors of revision amongst only patients who required surgical revision for reasons other than infection. CONCLUSIONS: Shunt revision amongst iNPH patients is associated with factors relating to surgical technique. Shunt revision rates appear lower amongst patients with VPS using an occipital proximal catheter with an adjustable valve and laparoscopic distal catheter placement.

In this study, we have summarized the various myelographic techniques that are used for CSF leak localization. These include conventional CTM, intrathecal GdM, dynamic myelography, DSM, dynamic CTM, decubitus CTM. We have also discussed PCD CTM, highlighting its advantages as they pertain to improving dynamic and decubitus CTM techniques for localizing CSF leaks. Currently, all of these techniques are used by different institutions for CSF leak localization. To date, comparative evidence assessing the relative sensitivity of these modalities is lacking. One recent study directly compared DSM and EID CTM, finding the latter to have a higher yield for CVF detection.25 Further studies similar to this will be particularly helpful. Generally, dynamic myelography, DSM, EID CTM, and PCD CTM are considered the best techniques for CSF leak localization. Among these, PCD CTM shows promise as potentially being the most sensitive technique, though more data must be accrued to establish this.

BACKGROUND AND PURPOSE:Photon-counting detector CT myelography (PCD-CTM) is a recently described technique used for detecting spinal CSF leaks, including CSF-venous fistulas. Various image reconstruction techniques, including smoother-versus-sharper kernels and virtual monoenergetic images, are available with photon-counting CT. Moreover, denoising algorithms have shown promise in improving sharp kernel images. No prior studies have compared image quality of these different reconstructions on photon-counting CT myelography. Here, we sought to compare several image reconstructions using various parameters important for the detection of CSF-venous fistulas. MATERIALS AND METHODS:We performed a retrospective review of all consecutive decubitus PCD-CTM between February 1, 2022, and August 1, 2024, at 1 institution. We included patients whose studies had the following reconstructions: Br48-40 keV virtual monoenergetic reconstruction, Br56 low-energy threshold (T3D), Qr89-T3D denoised with quantum iterative reconstruction, and Qr89-T3D denoised with a convolutional neural network algorithm. We excluded patients who had extradural CSF on preprocedural imaging or a technically unsatisfactory myelogram-. All 4 reconstructions were independently reviewed by 2 neuroradiologists. Each reviewer rated spatial resolution, noise, the presence of artifacts, image quality, and diagnostic confidence (whether positive or negative) on a 1-5 scale. These metrics were compared using the Friedman test. Additionally, noise and contrast were quantitatively assessed by a third reviewer and compared. RESULTS:The Qr89 reconstructions demonstrated higher spatial resolution than their Br56 or Br48-40keV counterparts. Qr89 with convolutional neural network denoising had less noise, better image quality, and improved diagnostic confidence compared with Qr89 with quantum iterative reconstruction denoising. The Br48-40keV reconstruction had the highest contrast-to-noise ratio quantitatively. CONCLUSIONS:In our study, the sharpest quantitative kernel (Qr89-T3D) with convolutional neural network denoising demonstrated the best performance regarding spatial resolution, noise level, image quality, and diagnostic confidence for detecting or excluding the presence of a CSF-venous fistula.

CSF-venous fistulas (CVFs) are a common and increasingly recognized type of spinal CSF leak. Most of these fistulas occur in the setting of spontaneous intracranial hypotension, though nonspontaneous cases have been described as well. In most instances, CVFs arise from the dome or neck of nerve root sleeve diverticula (also called meningeal diverticula). Venous drainage typically involves some combination of the internal epidural venous plexus and external vertebral venous plexus. Not uncommonly, venous drainage into the basivertebral venous plexus or other intraosseous veins can be seen. However, the drainage is usually a secondary finding related to normal communication between intraosseous and extraosseous veins. We have recently observed unique cases in which CVFs arise directly within the vertebral elements, resulting in primarily intraosseous drainage. It is possible that this phenomenon is secondary to prominent meningeal diverticula remodeling the adjacent vertebral elements. In this clinical report, we reviewed a multi-institutional series of CVFs exhibiting primary intraosseous drainage, with the goal of illustrating the imaging findings, treatment strategies, and outcomes of the patients. Nine cases were identified demonstrating this phenomenon. We show that intraosseous CVFs can arise in virtually any part of the vertebrae and describe how this feature affects treatment.

OBJECTIVE:The objective of this study was to summarize the available evidence regarding the clinical value and trend over time of lumbar cerebrospinal fluid (CSF) opening pressure utilization to diagnose spontaneous intracranial hypotension (SIH). BACKGROUND:CSF opening pressure obtained via lumbar puncture is one of the diagnostic criteria for SIH based on the International Criteria for Headache Disorders, 3rd Edition (ICHD-3), but it has questionable utility as an initial investigation for diagnosing SIH. METHODS:The authors performed a systematic literature review and meta-analysis. PubMed/MEDLINE, Scopus, and Cochrane Library were searched from inception to October 2022. Original studies and case series in English reporting three or more patients with suspected or known SIH and CSF pressure measurement were included. Meta-analyses and meta-regression were used to calculate pooled estimates and examine the impact of age, sex, and publication year on outcomes, including CSF pressure < 60 mm CSF, orthostatic headache, and positive findings on brain magnetic resonance imaging (MRI), spinal imaging, and radionuclide studies. RESULTS:For every 1-year increase in the year of publication, the odds of reporting low CSF pressure decreased by 6.20% (adjusted odds ratio [aOR] = 0.94, aOR 95% confidence interval [CI] = [0.90, 0.97], p = 0.001), the odds of reporting a positive brain MRI increased by 4.67% (aOR = 1.05, aOR 95% CI = [1.01, 1.09], p = 0.026), and the odds of reporting orthostatic headache increased by 9.13% (aOR = 1.09, aOR 95% CI = [1.03, 1.15], p = 0.002). Each 1% increase in the percentage of patients with orthostatic headache was associated with a 3.13% increase in the odds of low CSF pressure (aOR = 1.03, aOR 95% CI = [1.01, 1.05], p = 0.003). Similarly, as the percentage of patients with low CSF pressure increased by 1%, there was a 2.53% increase in the odds of orthostatic headache (aOR = 1.03, aOR 95% CI = [1.01, 1.04], p = 0.005). It was estimated that 31.9% of patients with SIH had normal opening pressure (95% CI = [24.0%, 40.8%], prediction interval = [5.0%, 80.5%]). Every 1% increase in the percentage of patients with positive brain MRI was associated with a 5.25% increase in the odds of positive spinal imaging (aOR = 1.05, aOR 95% CI = [1.00, 1.11], p = 0.047). Age and positive radionuclide study did not significantly impact the outcomes measured. The corresponding I2 for each outcome was reduced by controlling for study-wide covariates believed to impact the prevalence of each outcome. Sensitivity analyses did not reveal discrepancies in results when studies requiring outcomes of interest were removed. CONCLUSION:Our analysis found that recent studies indicate a reduced reliance on opening pressure for diagnosing SIH. Rather, results suggest an increasing reliance on contrast-enhanced brain MRI, spine imaging, and clinical features for SIH diagnosis.

OBJECTIVE:This article reviews the preoperative considerations, postoperative complications, and ongoing management of shunts for normal pressure hydrocephalus. LATEST DEVELOPMENTS:The radiographic pattern of disproportionately enlarged subarachnoid space hydrocephalus (DESH) predicts a positive response to permanent CSF diversion. MRI-safe programmable shunt valves allow for fluid drainage adjustment based on patients' symptoms and radiographic images. Endoscopic third ventriculostomy is a viable alternative to shunting for patients with normal pressure hydrocephalus due to aqueductal stenosis. ESSENTIAL POINTS:Approximately 75% of patients with normal pressure hydrocephalus improve after shunt surgery regardless of shunt type or location. Clinical benefit and complication rates are similar for frontal and parietal ventricular catheter approaches. Acetazolamide is not an effective treatment for normal pressure hydrocephalus.