Relationship between thrombus density on CT scans and recanalization rate in acute middle cerebral artery occlusion

Mechanical thrombectomy has proven to be highly effective for acute ischemic stroke because of the advent of novel devices for intervention. However, we have encountered some cases where recanalization is challenging. In this study, we investigated the relationship between the thrombus density on computed tomography (CT) scans and the recanalization rate or the clinical outcomes in patients with acute occlusion of the proximal segment of the middle cerebral artery (M1). The thrombus density was calculated as the rate of the average density at the occluded M1 segment to that of the contralateral M1 based on the axial views of the plain CT scans before thrombectomy. The thrombolysis in cerebral infarction (TICI) grading scale and the modified Rankin scale were used for the evaluation of the recanalization rate and the clinical outcomes, respectively. This study included 76 cases with M1 occlusion, and the successful recanalization with TICI 2b-3 was achieved in 72 cases (94.7%). The mean thrombus density of the TICI 2b-3 group was significantly higher than that of the TICI 0-2a group (1.54 vs 1.34, p = 0.03). We calculated the cutoff value of thrombus density as 1.42 for the clinical outcomes (sensitivity = 0.792, specificity = 1.000, area under the curve = 0.858). In conclusion, we can predict the difficulty of recanalization therapy by rapidly analyzing the CT scans. A detailed investigation is required to identify the association of thrombus density on CT scans with clinical outcomes and treatment strategies. (author)