Systematic review and meta-analysis of MRI-based cerebrospinal fluid flow reference values in normal pressure hydrocephalus: unveiling diagnostic inconsistencies.

PURPOSE: The primary aim of this meta-analysis is to assess the consistency and reliability of MRI-based cerebrospinal fluid (CSF) flow reference values in the diagnosis of Idiopathic Normal Pressure Hydrocephalus (iNPH). The research seeks to identify the sources of variability in CSF flow measurements and evaluate which parameters offer the most reliable diagnostic value.

METHODS

A systematic review and meta-analysis were conducted following PRISMA guidelines. Relevant studies were identified through a comprehensive search in PubMed. The inclusion criteria focused on studies reporting quantitative CSF flow parameters such as Stroke Volume (SV), Peak Systolic Velocity (PSV), Peak Diastolic Velocity (PDV), and Mean Flow (MF) in iNPH patients. Data were synthesized using a random-effects model, and heterogeneity was assessed using the I2 statistic.

RESULTS

The analysis revealed significant variability in SV and PSV across studies, likely driven by differences in MRI protocols, equipment, and patient populations. MF, however, consistently showed elevated values in iNPH patients compared to controls (effect size: 0.143 ml/s; 95% CI: 0.131-0.155 ml/s), suggesting its potential as a reliable diagnostic marker for iNPH.

CONCLUSION

MF appears to be the most reliable parameter for diagnosing iNPH, given its consistency across studies. However, the substantial variability in SV and PSV underscores the need for standardized MRI protocols to improve the diagnostic accuracy of CSF flow measurements. Future research should prioritize the development of unified imaging protocols to reduce heterogeneity and enhance diagnostic reliability in iNPH.