Flat Detector Angio-CT following Intra-Arterial Therapy of Acute Ischemic Stroke: Identification of Hemorrhage and Distinction from Contrast Accumulation due to Blood-Brain Barrier Disruption

BACKGROUND AND PURPOSE:Flat panel detector CT in the angiography suite may be valuable for the detection of intracranial hematomas; however, abnormal contrast enhancement frequently mimics hemorrhage. We aimed to assess the accuracy of flat panel detector CT in detecting/excluding intracranial bleeding after endovascular stroke therapy and whether it was able to reliably differentiate hemorrhage from early blood-brain barrier disruption.MATERIALS AND METHODS:Seventy-three patients were included for retrospective evaluation following endovascular stroke therapy: 32 after stent-assisted thrombectomy, 14 after intra-arterial thrombolysis, and 27 after a combination of both. Flat panel CT images were assessed for image quality and the presence and type of intracranial hemorrhage and BBB disruption by 2 readers separately and in consensus. Follow-up by multisection head CT, serving as the reference standard, was evaluated by a single reader.RESULTS:Conventional head CT revealed intracranial hematomas in 12 patients (8 subarachnoid hemorrhages, 7 cases of intracerebral bleeding, 3 SAHs plus intracerebral bleeding). Image quality of flat panel detector CT was considered sufficient in all cases supratentorially and in 92% in the posterior fossa. Regarding detection or exclusion of intracranial hemorrhage, flat panel detector CT reached a sensitivity, specificity, positive and negative predictive values, and accuracy of 58%, 85%, 44%, 91%, and 81%, respectively. Maximum attenuation measurements were not valuable for the differentiation of hemorrhage and BBB disruption.CONCLUSIONS:Flat panel CT after endovascular stroke treatment was able to exclude the rare event of an intracranial hemorrhage with a high negative predictive value. Future studies should evaluate the predictive value of BBB disruptions in flat panel detector CT for the development of relevant hematomas.

Flat panel detectors in modern angiographic C-arm systems allow almost instant access to CT-like cranial imaging in the angiography suite.^1–4 While flat panel detector CT (FPCT) is currently not reliable in depicting ischemic brain lesions, it proved to be a sensitive tool for the detection of intracranial hematomas in both experimental and clinical settings.^5,6 However, there have been numerous reports of abnormal contrast enhancement following neurovascular interventions that frequently mimic subarachnoid, intraventricular, or intracerebral hemorrhage.^7–9 It is important to recognize such patterns of temporary blood-brain barrier disruption in postprocedural imaging because misinterpretation may unnecessarily delay anticoagulant/antiaggregant treatment.In the present study, we aimed to assess the diagnostic accuracy of FPCT for the detection of intracranial bleeding immediately after endovascular stroke therapy and whether it was able to reliably differentiate hemorrhage from early blood-brain barrier disruption.