Introduction A recently developed multiphase-computed-tomography-angiography(mCTA) tool generates perfusion maps, similar to CT-perfusion(CTP) (i.e., mCTA-perfusion[mCTAp]).

Aim of Study To validate the clinical utility of mCTAp.

Methods In this multi-reader-multi-case analysis, we included baseline images: mCTAp(StrokeSENS-algorithm) and CTP(4D; GE-Healthcare) from 121 randomly selected patients whose scans were not part of algorithm-development. After excluding 2/121 scans due to poor image-quality, three experienced radiologists read Tmax-and rCBF-maps generated by the test(mCTAp) and reference(CTP) modality. The two reading sessions were separated by 5-days with randomized reading order. Core-laboratory imaging assessments-that used NCCT, mCTA and CTP-were considered as ground-truth. We used ‘reader’ as a random-effect to calculate the diagnostic performance for both modalities(mCTAp/CTP) regarding ischemia detection and side/location. Interpretation-time and inter-rater variability were compared across the modalities.

Results AUCs(95%CI) for detecting ischemia using mCTAp and CTP were 0.85(95%CI0.8–0.9) and 0.84(0.8–0.9) respectively(p=0.43). AUCs for the affected side were 0.94(0.92–0.97) and 0.96(0.94–0.98) (p=0.69) respectively; for detecting LVO were 0.84(0.8–0.9) and 0.86(0.8–0.9), (p=0.31) respectively; M2-or-distal occlusion were 0.79(0.73–0.84) and 0.88(0.83–0.92) (p=0.22) respectively, for ACA-occlusion 0.82(0.66–0.98) and 0.93(0.82–1.00) (p=0.15) respectively and for PCA-occlusions 0.9(0.8–1) and 0.99(0.98–0.99) (p=0.01) respectively. The median(IQR) time for image interpretation was 62s(IQR 46–78) and 59s(IQR 42–69) for mCTAp and CTP respectively (p=0.15). Fleiss` Kappa-values for inter-rater reliability in detecting ischemia were 0.5 and 0.8 for mCTAp and CTP respectively.

Conclusion mCTAp shows similar performance compared to CTP in assisting readers to detect ischemia and its side/location, requiring less radiation exposure, acquisition time and contrast-dose compared to additional-CTP, but mainly as it relates to proximal vessel occlusions.

Disclosure of Interest Dr. Menon holds patents on systems of triage in acute stroke, for LVO detection and for mCTAp, and stock ownership in Circle Cardiovascular Inc. Dr. Bala has nothing to declare. Dr. Duszynski is an employee of, and holds stock options for Circle Cardiovascular Imaging Inc. Dr. Nayem Pinky, Dr. Golan and Luis A Souto Maior Neto are employees of Circle Cardiovascular Imaging Inc. All other co-authors have nothing to disclose.