Tag: Diagnostic performance

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Diagnosing Cerebrospinal Fluid Shunt Failure: Systematic Review and Meta-Analysis of Noninvasive and Minimally Invasive Tests in Children and Adults

Neurosurgery 98:1206–1220, 2026

This systematic review and meta-analysis evaluates diagnostic performance of noninvasive and minimally invasive tests (X-ray shunt series, CT, MRI, nuclear scintigraphy, thermal flow) for cerebrospinal fluid shunt failure in pediatric and adult patients, synthesizing 33 studies and 8,077 patients. Pooled accuracy was 82%, sensitivity 67%, and specificity 88%, with X-ray series showing lower sensitivity but higher specificity compared with CT.

The analysis highlights substantial study bias—especially in patient selection and reference standards—and concludes no existing test is adequate as a standalone diagnostic for shunt failure, underscoring the need to optimize diagnostic pathways, reduce harm, and develop improved point-of-care functional tests.

Objective Assess diagnostic performance of noninvasive/minimally invasive tests (X-ray shunt series, CT, MRI, nuclear scintigraphy, thermal flow evaluation) for suspected CSF shunt failure in pediatric and adult patients.

Methods Systematic review/meta-analysis (PROSPERO CRD42024596142) including patients with permanent CSF shunts who underwent the above index tests; performance (accuracy, sensitivity, specificity) modeled via meta-regression incorporating test type, age group, follow-up timeframe, and shunt type.

Evidence base PubMed search (Oct 22, 2024) screened 465 articles; 33 studies included, totaling 8077 patients.

Pooled performance Overall pooled accuracy 82%, sensitivity 67%, specificity 88% across included tests.

Key comparative finding (sensitivity) X-ray shunt series had significantly lower sensitivity than CT (OR 0.106, 95% CI 0.056–0.201; overall effect of test type on sensitivity P = .013).

Key comparative finding (specificity) No overall effect of test type on specificity (P = .192), but X-ray shunt series showed higher specificity than CT in subgroup analysis (OR 4.04, 95% CI 1.938–8.424).

Covariates No significant effects of age group, follow-up timeframe, or shunt type on accuracy, sensitivity, or specificity.

Conclusion/limitations No test performed well enough to serve as a standalone diagnostic for shunt failure; evidence limited by high risk of bias, especially in the reference standard domain for most studies.

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A Multicenter Study of Noninvasive Wireless Assessment of Cerebrospinal Fluid Shunt Function in Hydrocephalus Patients

Neurosurgery 97:1397–1405, 2025

This multicenter prospective study evaluates a wearable, wireless thermal anisotropy sensor for noninvasive detection of cerebrospinal fluid (CSF) shunt flow in symptomatic hydrocephalus patients. Using a random forest algorithm on data from 112 validated subjects, the device showed high sensitivity (88.9%) and a very high negative predictive value (96.8%), though specificity was modest (49.2%) and a 37.5% no-result rate occurred.

Methods, usability, and comparative analyses are detailed: device design, algorithm development, blinded validation, and 7-day surgical follow-up with intraoperative confirmation as ground truth. Ease-of-use was rated highly, adverse events were minor skin reactions, and combined use with CT/MRI improved specificity and overall accuracy, supporting adjunctive clinical application.

Device Purpose: A novel, noninvasive, wireless wearable device was developed to assess cerebrospinal fluid (CSF) shunt flow in hydrocephalus patients presenting with possible shunt failure, using thermal anisotropy measurements to detect flow through the shunt tubing.

Study Design: The prospective, blinded, multicenter study included both pediatric and adult patients with existing ventriculoperitoneal shunts and symptoms suggestive of shunt failure; subjects underwent device evaluation alongside standard-of-care assessments.

Algorithm Performance: The device’s random forest algorithm demonstrated high sensitivity (88.9%) and negative predictive value (NPV, 96.8%) but moderate specificity (49.2%) for detecting complete shunt failure, indicating strong ability to rule out failure when flow is confirmed.

Clinical Utility: The high NPV suggests the device could help identify patients whose shunts are functioning, potentially reducing unnecessary surgical interventions or additional invasive tests.

Comparison with Standard Tests: Standard imaging tests (CT/MRI) showed moderate-to-high sensitivity and specificity but require radiation or sedation, whereas the device is noninvasive, wireless, and does not require such resources.

Combined Diagnostic Approach: When device results were combined with CT or MRI findings, specificity increased to 93.3% and NPV to 96.6%, supporting a potential workflow where the device is used to complement imaging for risk stratification.

Safety and Usability: The device was rated as easy to use by clinicians, with a low rate of mild, self-resolving skin redness and no serious adverse events reported.

Limitations: The device is not suitable as a stand-alone diagnostic tool due to moderate specificity and a substantial rate of incomplete measurements; further studies are ongoing to optimize performance and generalizability.

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