DWI Cerebellar Infarct Volume as Predictor of Outcomes After Endovascular Treatment of Acute Basilar Artery Occlusion

Acute basilar artery occlusion (ABAO) is a rare and devastating type of stroke. Endovascular treatment (EVT) is routinely performed in real-world practice, encouraged by guidelines from learned societies, and the recent result of the basilar artery international cooperation study (BASICS), a randomized controlled study.

ABAO may result in infarcts in the brainstem, cerebellar lobes, thalamus and subthalamic area, or occipitotemporal lobes. Previously, studies using the DWI Posterior-circulation Alberta Stroke Program Early CT (Pc-ASPECT) Score or brainstem score, for predicting outcome in patients with ABAO showed conflicting results. The rational for the brainstem scoring system was based on the anatomic architecture and the regional eloquence of brainstem, which may negatively influence functional outcome.

Nevertheless, one of the most significant and immediate dreaded complication, in patients with ABAO and cerebellar infarcts, is the development of a space-occupying edema. Due to the small volume of posterior fossa, cerebellar infarct with mass effect (CIMASS) contribute to a risk of catastrophic herniation with direct brainstem compression, hydrocephalus due to blockage of the fourth ventricle, or both. Up to 25% of patients with CIMASS deteriorate clinically resulting in morbidity and in mortality in 85% of patients without intervention. This potential risk of CIMASS, lead clinicians to strengthen clinical and radiological monitoring and modify therapeutic management with the recourse of live-saving suboccipital decompressive craniectomy (SDC), as recommended by learned societies.

Until now, little is known about predicting factors of outcomes in patients with ABAO treated by EVT and associated cerebellar infarct. In fact, there are no focusing research to assess if baseline cerebellar infarct volume (CIV) may correlate with 90-day clinical outcome and mortality, nor if such lesions would affect a reperfusion decision.

Using data of our prospective registry, the investigators analyzed consecutive MRI selected, endovascularly treated ABAO patients within the first 24h after symptom-onset. Using the initial Magnetic Resonance Imaging (MRI), baseline CIV was calculated in mL, on an apparent diffusion-coefficient map reconstruction (Olea sphere software).