Association between periventricular white matter hyperintensities around the anterior horn and CSF tap test responsiveness in idiopathic normal pressure hydrocephalus.

BACKGROUND

White matter hyperintensities (WMH) are common in idiopathic normal pressure hydrocephalus (iNPH), particularly in periventricular regions around the anterior horns. However, their quantitative evaluation using simple and reproducible methods and their association with cerebrospinal fluid (CSF) tap test responsiveness remain insufficiently studied. We investigated whether the extent of periventricular WMH around the anterior horn area is associated with responsiveness to the CSF tap test.

METHODS

We retrospectively reviewed patients who underwent a CSF tap test and preprocedural MRI between January 2020 and September 2023. Periventricular WMH around the anterior horn area was manually quantified on axial T2-weighted fluid-attenuated inversion recovery images using freehand regions of interest. Gait and cognitive function were assessed using the 3-m Timed Up and Go test (3-TUG) and the Frontal Assessment Battery (FAB). Correlation, multivariable regression, and receiver operating characteristic (ROC) analyses were performed.

RESULTS

Thirty-six patients were included. Inter-rater reliability for WMH measurements was good (intraclass correlation coefficient = 0.73). Larger WMH areas were associated with lower baseline FAB scores and longer disease duration. Although correlations with changes in 3-TUG or FAB scores were not significant, greater WMH burden was associated with smaller improvement after the CSF tap test. Multivariable analysis showed that WMH area independently predicted FAB score improvement. ROC analysis identified a WMH cutoff value of 254 mm2 for predicting ≥ 3-point FAB improvement (area under the curve = 0.728).

CONCLUSIONS

Quantitative assessment of periventricular WMH around the anterior horn area may help predict cognitive responsiveness to the CSF tap test iNPH.