Background and Purpose Hemorrhagic transformations are pejorative for patients with acute ischemic stroke (AIS). We evaluated flat panel CT (FPCT) to detect enhancing brain parenchymal lesions immediately after mechanical thrombectomy (MT) in AIS patients and its ability to predict hemorrhagic transformation within 24 h. The second objective was to evaluate an easy-reading protocol for post-procedure FPCT evaluation by clinicians to enable them to determine the potential risk of hemorrhagic transformation.

Material and Methods Two neuroradiologists retrospectively and independently reviewed FPCT and 24-h follow-up imagery for AIS patients revascularized by MT. We evaluated brain parenchymal enhancement on FPCT and evaluated its power to predict the occurrence of hemorrhagic transformation within 24 h detected with conventional cross sectional imaging (CT, MR) on 63 consecutive patients. κ test was used for inter observer agreement.

Results We observed a large homogeneity between the different readers (two neuradiologists and one intensivist). Thirty-eight patients were followed at 24 h with conventional non-enhanced CT, 25 patients with MRI. 60.3% of the 63 included patients presented a post procedural parenchymal enhancement and 53.9% had hemorrhagic transformation. 84.2% of patients with enhancement presented hemorrhagic transformation, vs 8.0% of the patients without enhancement (p<0.0001). No significant hemorrhagic transformations were detected on the 24-h follow-up for patients without enhancement. Sensibility and specificity of enhancing parenchymal lesions on FPCT for the prediction of hemorrhagic transformation were respectively 94.1% (80.3–99.3) and 79.3% (60.3–92.0). The positive and negative predictive values for the occurrence of a hemorrhagic transformation were 84.2% (68.8–94.0) and 92% (74.0–99.0). For significant PH2 hemorrhagic transformation, sensibility and negative predictive value of FPCT were 100%.

Conclusions In the light of our results, FPCT can be deemed as effective as conventional CT scans to predict the risk of 24 h hemorrhagic transformation. FPCT is cost effective and augments patient safety in the setting of MT of AIS patients.

Competing interests None.