Association between flat-panel computed tomography hyperattenuation and clinical outcome after successful recanalization by endovascular treatment

OBJECTIVE Hyperattenuation on CT scanning performed immediately after endovascular treatment (EVT) is known to be associated with the final infarct. As flat-panel CT (FPCT) scanning is readily accessible within their angiography suite, the authors evaluated the ability of the extent of hyperattenuation on FPCT to predict clinical outcomes after EVT. METHODS Patients with successful recanalization (modified Thrombolysis in Cerebral Infarction grade 2b or 3) were reviewed retrospectively. The extent of hyperattenuation was assessed by the Alberta Stroke Program Early CT Score on FPCT (FPCT-ASPECTS). FPCT-ASPECTS findings were compared according to functional outcome and malignant infarction. The predictive power of the FPCT-ASPECTS with initial CT images before EVT (CT-ASPECTS) and follow-up diffusion-weighted images (MR-ASPECTS) was also compared. RESULTS A total of 235 patients were included. All patients were treated with mechanical thrombectomy, and 45.5% of the patients received intravenous tissue plasminogen activator. The mean (± SD) time from stroke onset to recanalization was 383 ± 290 minutes. The FPCT-ASPECTS was significantly different between patients with a favorable outcome and those without (mean 9.3 ± 0.9 vs 6.7 ± 2.6) and between patients with malignant infarction and those without (3.4 ± 2.9 vs 8.8 ± 1.4). The FPCT-ASPECTS was an independent factor for a favorable outcome (adjusted OR 3.28, 95% CI 2.12–5.01) and malignant infarction (adjusted OR 0.42, 95% CI 0.31–0.57). The area under the curve (AUC) of the FPCT-ASPECTS for a favorable outcome (0.862, cutoff ≥ 8) was significantly greater than that of the CT-ASPECTS (0.637) (p < 0.001) and comparable to that of the MR-ASPECTS (0.853) (p = 0.983). For malignant infarction, the FPCT-ASPECTS was also more predictive than the CT-ASPECTS (AUC 0.906 vs 0.552; p = 0.001) with a cutoff of ≤ 5. CONCLUSIONS The FPCT-ASPECTS was highly predictive of clinical outcomes in patients with successful recanalization. FPCT could be a practical method to immediately predict clinical outcomes and thereby aid in acute management after EVT.