Prognostic value of perivascular spaces, diffusion tensor imaging-derived indices, and choroid plexus in idiopathic...

This study investigated the ability of the perivascular space (PVS), free water in the white matter (FW-WM), diffusion tensor imaging analysis along the PVS (DTI-ALPS), and choroid plexus (CP) to predict postoperative prognosis for idiopathic normal pressure hydrocephalus (iNPH), and the relationships between these MRI indices and clinical phenotypes. This retrospective study included patients with iNPH who underwent magnetic resonance imaging (MRI). MRI indices included the PVS volume fraction (PVSVF), FW-WM fractional volume, DTI-ALPS, and CP volume fraction (CPVF). Predictors of improvement were analyzed using a logistic regression model and receiver operating characteristic analysis. The primary endpoint was the improvement in the modified Rankin Scale (mRS) score at 1 year after surgery; secondary endpoints were the iNPH grading scale (iNPHGS), Mini-Mental State Examination (MMSE), and Timed Up-and-Go (TUG) test at 1 year. Multiple comparisons were controlled using the false discovery rate (FDR). The 32 enrolled patients (70 ± 7 years) included 17 men. The improvement rates in mRS, iNPHGS, MMSE, and TUG were 56% (18/32), 59% (19/32), 60% (15/25), and 57% (12/21), respectively. No significant differences in the examined MRI indices or clinical symptoms were observed between improved and non-improved groups for either the primary or secondary outcomes (all p > 0.05). Lower DTI-ALPS scores were correlated with lower MMSE scores (r = 0.542, p_FDR = 0.007). Higher FW-WM was correlated with higher TUG time (r = 0.546; p_FDR = 0.011) and steps (r = 0.507; p_FDR = 0.013). Preoperative PVSVF, DTI-ALPS, FW-WM, and CPVF showed no significant associations with postoperative outcomes in this cohort. Higher FW-WM scores were correlated with gait impairment, whereas lower DTI-ALPS scores were correlated with cognitive impairment.