Apparent Diffusion Coefficient and Transient Neurological Deficit after Revascularization Surgery in Moyamoya Disease

BackgroundTransient neurological deficits are relatively common after direct revascularization surgery for moyamoya disease (MMD). Although recent evidence has revealed the clinical features and pathophysiology, preoperative predictors have remained unclear. This study investigated whether the apparent diffusion coefficient (ADC) in normal-appearing white matter (NAWM) on magnetic resonance imaging could offer a predictor of postoperative transient neurological deficits.MethodsThis study included adult patients with MMD who underwent superficial temporal artery-middle cerebral artery bypass. Preoperative ADCs were measured in NAWM on ipsilateral hemisphere. Single photon emission computed tomography (SPECT) with 123I-iodoamphetamine was performed on postoperative days 2-6. Relationships between mean ADC and postoperative transient neurological deficits were assessed.ResultsTwenty of the 26 subjects (76.9%) experienced transient neurological deficits. Focal hyperemia on postoperative SPECT appeared in 11 of the 20 subjects with postoperative transient neurological deficits and 1 of the 6 subjects without (P = .12). Mean ADCs in patients with and without postoperative transient neurological deficits were 748.3 ± 12 mm2/second × 10−6 and 679.7 ± 21.9 mm2/second × 10−6, respectively (P = .0091).ConclusionsPreoperative ADC elevation in NAWM may indicate postoperative transient neurological deficits not only in patients with postoperative hyperemia on SPECT, but also in patients with this pathology.