Abstract
BACKGROUND: Computed tomography angiography (CTA) is an effective means to detect atherosclerosis yet a whole-body scan may involve excessive dose that can only be considered in extreme cases. This study is to test the feasibility and value of adding a low-dose body CTA to the combined coronary-craniocervical CTA by using artificial intelligence iterative reconstruction (AIIR). METHODS: A total of 100 patients scheduled for one-stop combined coronary-craniocervical CTA were enrolled to receive an extended CTA covering from intracranial to iliofemoral arteries, by adding a low-dose body CTA to the coronary-craniocervical CTA. Radiation dose, contrast medium volume and the resulting image quality of the added scan, reconstructed by the AIIR, were compared to those from the retrospectively collected routine-dose aortic CTA. Diagnostic findings beyond the coronary and craniocervical arteries, which would have been missed if not for the extension, and their influence on clinical management, were assessed on the low-dose images. RESULTS: With rather low cost of radiation and contrast dosage (1.6 mSv, 25.4 mL), the body CTA with AIIR reconstruction yielded diagnostically sufficient image quality and significantly higher contrast-to-noise ratio (CNR) as compared to routine-dose aortic CTA at various vascular locations (all P<0.05). Additional atherosclerosis was detected by the added low-dose body CTA for a substantial proportion of patients (73/100, 73%). Incidental findings in the body were found in 26 patients with 44 detections. The corresponding clinical management of 38% patients was changed due to the atherosclerotic and non-atherosclerotic vascular findings on body arteries. Most of the atherosclerosis were calcified plaques (38/73, 52%) and rated as mild stenosis (62/73, 85%). The prevalence of body arterial atherosclerosis was remarkably higher among patients diagnosed with coronary-craniocervical atherosclerosis than those without coronary-craniocervical atherosclerosis (85% vs. 22%). CONCLUSIONS: Extending the one-stop combined coronary-craniocervical CTA with low-dose body coverage as enabled by the AIIR is technically feasible and of evident clinical value in clinical decision-making, taking a concrete step towards multi-territorial atherosclerosis diagnosis and management in practical application.