Diffusion-weighted MRI helps predict outcome in basilar artery occlusion patients treated with intra-arterial thrombolysis

Background: Intra-arterial thrombolysis (IAT) can improve clinical outcome in patients with acute basilar artery occlusion (BAO). The purpose of this study was to determine whether the severity of neurological symptoms, the extent of early ischemic damage on pretreatment diffusion-weighted MRI (DWI), and the lesion progression or regression on post-treatment MRI can predict functional outcome in patients with BAO treated with IAT.

Methods: Thirty-six BAO patients (13 women, 23 men; mean age 60 years) treated with IAT within 12 h of symptom onset were studied. Early ischemic damage on DWI was assessed by applying 4 DWI scoring systems, including a proposed DWI score developed for this study. The latter was used for evaluation of lesion dynamics on post-treatment MRI. The association of pretreatment DWI, severity of symptoms (National Institutes of Health Stroke Scale, NIHSS, and Glasgow Coma Scale, GCS, scores), vessel recanalization, and lesion progression or regression after IAT with clinical outcome at 3 months was analyzed.

Results: Median NIHSS and GCS scores on admission were 17 and 10, respectively. In univariate analysis, NIHSS and GCS scores (on admission) and all 4 DWI scores were significantly associated with clinical outcome. After regression analysis for each DWI score, the DWI score proposed herein was the only score that remained independently associated with clinical outcome at 3 months (p = 0.004). A decrease in DWI score was observed in 3 of 23 patients with post-IAT MRI. Successful recanalization was significantly associated with lesion regression (p = 0.044).

Conclusions: BAO patients with less extensive tissue damage on DWI and milder neurological deficits (lower NIHSS and higher GCS) have a better clinical outcome following IAT. The introduced DWI score reliably quantified the pretreatment ischemic damage and was an independent predictor of functional outcome. Lesion regression on DWI score after IAT was associated with vessel recanalization (p = 0.44), but had no impact on clinical outcome.