This study aimed to compare the anterior lateral ventricular index with established radiological markers, including the Evans Index, callosal angle, and disproportionately enlarged subarachnoid-space hydrocephalus, in evaluating postoperative radiological improvement in patients with idiopathic normal pressure hydrocephalus. A retrospective analysis was conducted on 46 patients who underwent ventriculoperitoneal shunt surgery between January 2019 and February 2025. Pre- and postoperative cranial computed tomography and magnetic resonance imaging scans were used to measure Evans Index, anterior lateral ventricular index, callosal angle and the presence of disproportionately enlarged subarachnoid-space hydrocephalus was assessed. Clinical parameters, including gait performance (10-meter walking and 360° turning steps) and urinary continence, were compared with radiological changes. Both Evans Index and anterior lateral ventricular index significantly decreased postoperatively (Evans Index: 0.388→0.336, p < 0.001; anterior lateral ventricular index: 0.552→0.479, p < 0.001), while callosal angle significantly increased (85.3°→99.7°, p < 0.05). Anterior lateral ventricular index reduction correlated moderately with Evans Index reduction (r = 0.37, p = 0.011) and weakly with callosal angle increase (r = 0.26, p = 0.080). Gait performance improved significantly (p < 0.001), and urinary incontinence resolved in 40.9% of affected patients. Anterior lateral ventricular index reduction showed stronger correlations with gait improvement (r = -0.45, p = 0.002) and continence recovery (r = -0.33, p = 0.024) compared with Evans Index or callosal angle. Disproportionately enlarged subarachnoid-space hydrocephalus positivity was not significantly associated with postoperative outcomes. These findings suggest that anterior lateral ventricular index may provide a more sensitive and clinically relevant linear measure than traditional indices and can serve as a complementary parameter to Evans Index and callosal angle in the postoperative evaluation of idiopathic normal pressure hydrocephalus.
DORUK et al. (Thu,) studied this question.