Abstract W MP13: Missed Imaging Diagnosis Without CT Perfusion May Affect Clinical Decision for TPA and Thrombectomy in Acute Stroke

Abstract

Purpose: In a previous study, we found higher detection rate of 2nd and 3rd order vascular thrombosis when CT Perfusion (CTP) was performed as compared to non-contrast CT (NCCT) and CT angiography (CTA) alone. Additionally, a significant number of patients with acute infarct were reported as negative without CTP. In this study, we sought to determine whether missed imaging diagnosis without CTP might affect clinical decision making. Methods: A total of 758 cases were included in our previous study, with CTP deficits reported in all 71 cases with final infarct volume of 2.8 ml or above. Conversely, 23 of 96 (24%) cases without CTP were reported as negative. In the group without CTP, 7 of 10 patients who had 2nd or 3rd order vascular thromboses with a final infarct > 30cc were reported negative, whereas only 1 of 10 cases were missed in patients who had CTP but a negative NCCT. The treatment decisions at the time of stroke were reviewed for these patients. Results: In 10 cases with final infarct volume > 30ml reported negative without CTP, zero received TPA or thrombectomy. Conversely, in the same category, 5 of 10 cases with positive CTP received TPA (p = 0.041). There was also a higher rate of TPA or thrombectomy treatment in patients with a positive imaging diagnosis, both with CTP (13 of 71, 18.3%) and without CTP (28 of 73, 38.4%), as compared to the group reported negative without CTP (3 of 23, 13%, p = 0.059). Fewer cases in the CTP group received treatment as compared to cases reported positive without CTP. A possible reason is that the cases with CTP were from an earlier phase of our acute stroke program, when treatment tended to be more conservative. Conclusions: Our study finds discrepancies in decision making for TPA and thrombectomy in stroke cases with positive versus negative imaging diagnosis. The cases reported negative were less likely to receive treatment, including those with relatively large final infarct size (>30ml). We speculate that a negative imaging diagnosis may create doubt for clinical diagnosis in some cases. Adding CTP in the acute stroke imaging protocol will increase imaging diagnostic accuracy and exclude stroke mimics, therefore providing valuable information for treatment.