A wide-detector CT protocol for one-stop cardio-cerebrovascular angiography: a technical feasibility study comparing an integrated protocol with conventional two-scan approach.

OBJECTIVE: To evaluate the clinical utility of a wide-detector CT protocol with variable helical pitch (vHP) for one-stop cardiovascular and cerebrovascular CT angiography. METHODS: This prospective randomized study enrolled 61 patients (25 in the Group A and 36 in the Group B) with suspected cardiovascular and cerebrovascular diseases. Group A underwent the integrated one-stop CTA protocol (which incorporates vHP technology), whereas Group B underwent conventional separate scans (coronary CTA and head-neck CTA). Both groups used automated bolus-tracking triggering. Comparisons included effective scanning time, total operating time, contrast medium volume, radiation dose (dose-length product, DLP), and subjective and objective image quality. Normality was assessed using the Shapiro-Wilk test; continuous variables were compared using independent samples t-test or Mann-Whitney U test as appropriate. The false discovery rate method was applied to correct for multiple comparisons, and analysis of covariance was performed to adjust for potential confounders. RESULTS: The integrated protocol group (Group A) demonstrated significantly higher contrast-to-noise ratio (CNR) in the coronary arteries and major aortic branches(all FDR-corrected P < 0.001). In the neck region, Group A showed significantly higher SNR in the common carotid arteries (FDR-corrected P < 0.001 for RCCA and P = 0.0044 for LCCA), whereas Group B demonstrated better CNR in the right internal carotid artery (FDR-corrected P < 0.001) and lower image noise in several vessels (FDR-corrected P < 0.05 for RICA SD and LVA SD). Notably, ANCOVA models for SNR exhibited poor fit with adjusted R2 values frequently near zero or negative, warranting cautious interpretation; the primary evidence for protocol-related image quality improvement is therefore based on the robust CNR findings. ANCOVA confirmed that these intergroup differences remained significant after adjustment (all adjusted P < 0.05 for key CNR/SNR comparisons), indicating protocol-related rather than baseline-driven advantages. Subjective image quality was excellent in both groups (median 4, IQR 4-4), with no significant intergroup differences. DLP was higher in Group A (909.00 vs. 694.50 mGy·cm, P < 0.001), but effective scanning time was significantly shorter (8.00 vs. 19.00 s, 57.9% reduction, P < 0.001), and total operating time was markedly reduced (480.00 vs. 1020.00 s, 52.9% reduction, P < 0.001). Contrast medium volume was halved in Group A (50-60 vs. 100-120 mL). CONCLUSION: The integrated wide-detector CT protocol evaluated in this study (which incorporates variable helical pitch as a key enabling component) is technically feasible and offers workflow advantages over conventional scanning, including shorter scan time, reduced contrast volume, and maintained image quality, with a somewhat higher radiation dose. However, lacking an independent reference standard, its diagnostic accuracy for detecting significant stenosis remains unproven. Further validation with invasive angiography is needed before routine clinical use. However, because the integrated protocol differs from the conventional protocol in multiple parameters simultaneously (detector configuration, rotation speed, pitch, and trigger threshold), the individual contribution of variable helical pitch cannot be isolated from these combined hardware and protocol differences.