Deep Learning–Based CT Perfusion-Derived CT Angiography for Enhanced Vascular and Thrombus Evaluation in Acute Ischemic Stroke

Accurate assessment of vascular status, collateral circulation, and occlusive thrombus is essential for acute ischemic stroke (AIS) management. This study evaluated the diagnostic performance and clinical value of CT perfusion–derived CT angiography (CTPA) reconstructed using a deep learning (DL) framework. This retrospective study included 288 patients who underwent both CTP and CTA examinations at two hospitals between November 2022 and May 2023. CTPA images were automatically reconstructed from CTP data using a DL-based workflow. Radiologists independently assessed CTPA and CTA image quality and diagnostic findings. Using digital subtraction angiography as reference, diagnostic performance was compared using the area under the curve (AUC) and the DeLong test. Associations between thrombus measurements, collateral score and stroke etiology were analyzed using regression models. No statistically significant difference was found in the subjective quality of axial images, although a trend favoring CTA was observed ( p = 0.082); CTPA yielded higher maximum intensity projection and volume rendering scores ( p < 0.05). CTPA achieved similar accuracy to CTA for ≥50% stenosis (AUC = 0.96 vs 0.95; p = 0.148) and superior accuracy for ≥70% stenosis (AUC = 0.98 vs 0.94; p = 0.006) and occlusion (AUC = 0.97 vs 0.94; p = 0.013) at vessel-level analysis. CTPA revealed higher thrombus attenuation and longer thrombus length (both p < 0.05), which were negatively associated with collateral score and stroke etiology (both p < 0.05). DL–derived CTPA provides comparable diagnostic performance to CTA while offering additional insights into thrombus and collateral evaluation, supporting CTPA as a valuable adjunct imaging tool for comprehensive AIS assessment. • Deep learning reconstructs CT angiography directly from perfusion data without extra contrast or radiation. • CTPA outperforms conventional CTA for detecting severe (≥70%) stenosis and large-vessel occlusion with improved vascular visualization. • CTPA enhances thrombus and collateral evaluation, enabling comprehensive stroke assessment from a single scan.