To determine the utility of the iNPH Radscale in predicting clinical outcomes of VPS placement in patients with NPH.

NPH is treated by placement of a VPS; however, there is no standardized approach to determining surgical candidacy. The iNPH Radscale is an established scoring system for CT/MRI scans that evaluates seven radiographic features characteristic of iNPH. A Radscale score of ≥8 suggests a high probability of an iNPH diagnosis. This study aimed to assess whether the pre-surgical iNPH Radscale could be used to help determine surgical candidacy.

Patients with a clinical diagnosis of NPH who underwent VPS placement between 1/1/10-6/30/21 were included in the study. The seven Radscale parameters were measured on patients’ pre-surgical MRIs. Patient charts were reviewed to determine clinical ambulation, cognition, and urination outcomes closest to one year post-VPS and were graded using the Clinical Global Impression Scale-Improvement (CGI-I). Chi-square and ANOVA were used to determine the relationship between total Radscale scores and CGI-I scores. The Fisher’s Exact Test was used to determine the association between each Radscale sub-score and CGI-I scores.

Out of 180 patients, 134 had complete Radscale scores and were included in this analysis. Fifty-nine percent had scores of ≥8, and 41% had scores <8. Forty-seven percent had CGI-I ambulation scores that reflected significant improvement, and 45% demonstrated insignificant improvement or worse outcomes. There was no evidence of a significant association between the total Radscale score and CGI-I scores after VPS; nor was there evidence of a significant association between the Radscale sub-scores and CGI-I outcomes.

This study suggests both total and sub-scores of the iNPH Radscale ratings based on pre-VPS placement imaging have no clear association with clinical improvement after VPS placement. Further research is needed to identify preoperative parameters that are predictive of positive shunt response.