Intraindividual comparison of contrast-free and contrast enhanced aortic angiography in magnetic resonance imaging

Abstract Introduction Contrast-enhanced (CE) angiography is currently the gold-standard for the evaluation of the aorta in magnetic resonance imaging (MRI). While modern gadolinium-containing contrast agents (CA) have a favorable safety profile, there is great interest in contrast-free techniques due to financial, environmental and safety-issues. Contrast-free steady-state-free-precession (SSFP) sequences for MR-angiography are available but have not been systematically compared to the gold standard of CE-angiography. Methods Between February 2022 and January 2024, a total of 54 patients with an indication for CA angiography of the thoracic aorta have been prospectively included for an intra-individual comparison of CE-angiography with SSFP-angiography before and after CA application. Reformatting and co-registering into corresponding vessel cross-sections, signal to noise ratio (SNR) of the lumen in the ascending aorta as well as maximum diameter measurements at seven prespecified locations (aortic root, sino-tubular Junction (STJ), ascending aorta, proximal aortic arch, medial aortic arch, distal aortic arch, descending thoracic aorta) were performed using an open source DICOM viewing and processing software (Horos, www.horosproject.org). ANOVA was performed to assess mean differences between techniques for SNR. Two-way-ANOVA with post-hoc tests was performed to assess differences in maximum diameter measurements between techniques at all seven measurement locations. A Bland-Altman-analysis was performed for maximum diameter measurements with CE-angiography and SSFP native at the aortic root. Results Five patients had to be excluded due to either incomplete data acquisition or insufficient image quality in one of the three sequences. In the remaining 49 patients, the mean SNR was lower in the CE-angiography compared to both the SSFP-angiography before and after CA application (14.86 vs. 21.3 vs. 22.25, p