Prediction of poor outcome in cerebellar infarction by diffusion MRI

Objective: Identification of patients with posterior fossa infarction at risk for neurological deterioration remains a challenge. MRI-based assessments of MCA infarction can predict poor outcome. Similar quantitative imaging measures after cerebellar stroke have not been studied. We tested the hypothesis that MRI-based volumetric assessment of cerebellar infarcts can provide reliable information for the prediction of poor outcome. Design: We retrospectively identified 44 consecutive subjects (age 55.2 ± 13) with cerebellar stroke who underwent MRI with diffusion-weighted imaging (DWI) (median 63.7 h). Subjects were divided into poor (n = 13) and good outcomes (n = 31). Poor outcome was defined as having at least one of the following criteria: (1) mortality, (2) decompressive craniectomy, (3) ventriculostomy, and (4) decrease level of consciousness. DWI and cerebellar volume were defined on apparent diffusion coefficient maps. The ratio of the lesion volume to the whole cerebellum volume was calculated (rVolume). Measurements and Main Results: Logistic regression revealed that lesion volume and rVolume were associated with increased risk of poor outcome, even after adjusting for age and NIHSS (χ ² = 8.2230, p < 0.0042; χ ² = 8.3992, p < 0.0038, respectively). The receiver operating characteristic curve with age, NIHSS, and volume or rVolume achieved an AUC of 0.816 (95 % CI 0.678-0.955) and 0.831 (95 % CI 0.6989-0.9636), respectively. Conclusions: Quantitative volumetric measurement predicts poor outcome of cerebellar stroke patients, even when controlling for age and NIHSS. Quantitative analysis of diffusion MRI may assist in identification of patients with cerebellar stroke at highest risk of neurological deterioration. Prospective validation is warranted.