Validation of collateral scoring on flat-detector multiphase CT angiography in patients with acute ischemic stroke

Background
The pivotal impact of collateral circulation on outcomes in endovascular therapy has fueled the development of numerous CTA collateral scales, yet synchronized validation with conventional angiography has never occurred. We validated multiphase flat-detector CTA (mpFDCTA) for collateral imaging in patients undergoing endovascular stroke treatment.
Materials and methods
Consecutive acute ischemic stroke patient data, including mpFDCTA shortly followed by digital subtraction angiography (DSA), in the setting of acute ICA- or MCA-occlusions were analyzed. An independent core lab scored mpFDCTA with an established collateral scale and separately graded American Society of Interventional and Therapeutic Neuroradiology (ASITN) collateral score 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 ICA- or MCA-occlusion were analyzed. Time from mpFDCTA to intracranial DSA was 23.04 ± 7.6 minutes. Median mpFDCTA collateral score was 3 (0–5) and median DSA ASITN collateral score was 2 (0–3), including the full range of potential collateral grades. mpFDCTA and ASITN collateral score were strongly correlated (r = 0.86, p<0.001). mpFDCTA provided more complete collateral data compared to selective DSA injections in cases of ICA-occlusion. ROC analyses for prediction of clinical outcomes revealed an AUC of 0.76 for mpFDCTA- and 0.70 for DSA ASITN collaterals.
Conclusions
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.

背景：侧支循环对缺血性脑卒中血管内治疗预后的关键影响，推动了多款CT血管造影（CT angiography，CTA）侧支分级量表的研发，但目前尚无与常规血管造影同步开展的验证研究。本研究针对接受缺血性脑卒中血管内治疗的患者，对多相平板探测器CT血管造影（multiphase flat-detector CTA，mpFDCTA）用于侧支循环成像的有效性进行了验证。

材料与方法：本研究分析了连续纳入的急性缺血性脑卒中患者数据，这些患者在完成mpFDCTA后短期内接受了数字减影血管造影（digital subtraction angiography，DSA）检查，且均存在急性颈内动脉（internal carotid artery，ICA）或大脑中动脉（middle cerebral artery，MCA）闭塞。由独立核心实验室采用已验证的侧支分级量表对mpFDCTA图像进行评分，并在盲法评估（不参考其他任何临床数据）的状态下，对DSA图像进行美国介入与治疗神经放射学学会（American Society of Interventional and Therapeutic Neuroradiology，ASITN）侧支评分分级。

结果：本研究共纳入24例急性ICA或MCA闭塞患者（平均年龄76.7±7.3岁，女性占比58.3%，基线美国国立卫生研究院卒中量表（National Institutes of Health Stroke Scale，NIHSS）中位数为17，四分位距4~23）进行分析。从mpFDCTA完成至颅内DSA检查的时间为23.04±7.6分钟。mpFDCTA侧支评分中位数为3（0~5），DSA的ASITN侧支评分中位数为2（0~3），覆盖了侧支分级的全部潜在区间。mpFDCTA侧支评分与ASITN侧支评分呈显著正相关（r=0.86，P<0.001）。对于ICA闭塞患者，mpFDCTA相较于选择性DSA造影可提供更完整的侧支循环数据。针对临床预后预测的受试者工作特征曲线（Receiver Operating Characteristic，ROC）分析结果显示，mpFDCTA的曲线下面积（Area Under Curve，AUC）为0.76，DSA的ASITN侧支评分AUC为0.70。

结论：血管造影室内开展的mpFDCTA可作为经过验证的侧支循环评估手段，相较常规血管造影具有显著优势。将患者直接转运至血管造影室并完成mpFDCTA侧支分级，可为急性缺血性脑卒中提供一种全新且可靠的分诊范式。