Background: The pivotal impact of collateral circulation on outcomes in endovascular therapy has fueled the development of numerous single and multiphase CTA collateral scales, yet synchronized validation with conventional angiography has never occurred. Multiphase flat detector CT angiography (mpFDCTA) enables direct patient transfer to the angiography suite and rapid collateral triage. We validated this novel collateral imaging paradigm and potential clinical utility for endovascular stroke treatment.
Methods: Consecutive acute ischemic stroke patient data, including mpFDCTA followed within few minutes by digital subtraction angiography (DSA), in the setting of ICA or proximal MCA occlusions were analyzed. An independent core lab scored mpFDCTA with an established multiphase CTA collateral scale and separately graded ASITN collateral status on DSA, blind to all other data.
Results: 24 consecutive cases (age 76.7 ± 7.3 years; 58.3% women; baseline NIHSS median 17 (4-23)) of acute stroke due to ICA or proximal MCA occlusion were analyzed with simultaneous mpFDCTA and DSA. Arterial occlusion sites included 18 M1 MCA, 5 ICA, 1 M2 MCA. ASPECTS was median 8 (4-10). Time from first noncontrast FDCT to intracranial DSA was 23.04 ± 7.6 minutes with mTICI ≥ 2b reperfusion in 91.7% of cases. mpFDCTA collateral score was median 3 (0-5) and DSA ASITN was median 2 (0-3), including the full range of potential collateral grades. mpFDCTA and ASITN were highly correlated (r=0.86, p<0.001). mpFDCTA provided more complete collateral data compared to selective DSA injections in cases of ICAO. ROC analyses for prediction of clinical outcomes revealed an AUC of 0.76 for mpFDCTA collaterals and 0.70 for DSA ASITN collateral grades.
Conclusions: Multiphase flat detector CT angiography (mpFDCTA) in the angiography suite provides a validated measure of collaterals, offering distinct advantages over conventional angiography. Direct patient transfer to the angiography suite and mpFDCTA collateral grading provides a novel and reliable triage paradigm for acute ischemic stroke.