Immediate postinterventional flat-panel CT: Differentiation of hemorrhagic transformation from contrast exudation of acute ischemic stroke patients after thrombectomy.

Background: Flat-panel computed tomography (CT) is an available imaging modality immediately after endovascular thrombectomy without transferring patients to the CT room.

Purpose: To determine the accuracy of flat-panel CT scans in differentiating hemorrhagic transformation (HT) from contrast exudation after thrombectomy in patients with acute ischemic stroke (AIS).

Material And Methods: From January 2019 to December 2021, consecutive patients with AIS who received an immediate flat-panel CT scan and follow-up neuroimaging after thrombectomy were enrolled in our study. The receiver operating characteristic curve was adopted to assess the discriminating accuracy of characteristics of flat-panel CT for HT.

Results: A total of 108 patients were enrolled in the study; 58 (53.7%) patients presented with hyperdense lesions on flat-panel CT. Patients with hyperdense lesions experienced a higher proportion of HT than patients without (58.7% vs. 10.0%;  < 0.001). Among all patients with hyperdensity on flat-panel CT, patients who experienced HT had higher average Hounsfield units (HUavg) (125 vs. 93;  = 0.001) and a higher proportion of mass effect (67.6 vs. 12.5;  < 0.001). The flat-panel CT differentiating HT from contrast exudation yielded a sensitivity of 87.2% and a negative predictive value of 90.0%. The area under the curve of HUavg, mass effect, and combination for differentiation of HT were 0.74, 0.78, and 0.83, respectively.

Conclusion: The hyperdensity on immediately post-thrombectomy flat-panel CT could differentiate HT from contrast exudation with an excellent negative predictive value. The ability of flat-panel CT in differentiating HT from contrast exudation was improved when combined with HUavg and mass effect.