A quantitative comparison between a navigated Cartesian and a self‐navigated radial protocol from clinical studies for free‐breathing 3D whole‐heart bSSFP coronary MRA

Abstract

Purpose Navigator‐gated 3D bSSFP whole‐heart coronary MRA has been evaluated in several large studies including a multi‐center trial. Patient studies have also been performed with more recent self‐navigated techniques. In this study, these two approaches are compared side‐by‐side using a Cartesian navigator‐gated and corrected (CNG) and a 3D radial self‐navigated (RSN) protocol from published patient studies. Methods Sixteen healthy subjects were examined with both sequences on a 1.5T scanner. Assessment of the visibility of coronary ostia and quantitative comparisons of acquisition times, blood pool homogeneity, and visible length and sharpness of the right coronary artery (RCA) and the combined left main (LM)+left anterior descending (LAD) coronary arteries were performed. Paired sample t‐tests with P < .05 considered statistically significant were used for all comparisons. Results The acquisition time was 5:40 ± 0:28 min (mean ± SD) for RSN, being significantly shorter than the 16:59 ± 5:05 min of CNG (P < .001). RSN images showed higher blood pool homogeneity (P < .001). All coronary ostia were visible with both techniques. CNG provided significantly higher vessel sharpness in the RCA (CNG: 50.0 ± 8.6%, RSN: 34.2 ± 6.9%, P < .001) and the LM+LAD (CNG: 48.7 ± 6.7%, RSN: 32.3 ± 7.1%, P < .001). The visible vessel length was significantly longer in the LM+LAD using CNG (CNG: 9.8 ± 2.7 cm, RSN: 8.5 ± 2.6 cm, P < .05) but not in the RCA (CNG: 9.7 ± 2.3 cm, RSN: 9.3 ± 2.9 cm, P = .29). Conclusion CNG provided superior vessel sharpness and might hence be the better option for examining coronary lumina. However, its blood pool inhomogeneity and prolonged and unpredictable acquisition times compared to RSN may make clinical adoption more challenging.

Measurement accuracy of prototype non-contrast, compressed sensing-based, respiratory motion-resolved whole heart cardiovascular magnetic resonance angiography for the assessment of thoracic aortic dilatation: comparison with computed tomography angiography

“…Moreover, we did not compare the proposed CMRA technique to the widely available Cartesian respiratory navigator gated CMRA method as CTA, an independent reference standard, was available in our patients. A previous study in healthy subjects investigating coronary arteries demonstrated signal homogeneity and time efficiency with the self-navigated technique, but inferior vessel sharpness [44]. Although, no vessel sharpness quantification was performed in the current study, we also did not visually observe limited sharpness when evaluating the aorta.…”

Efficient non-contrast enhanced 3D Cartesian cardiovascular magnetic resonance angiography of the thoracic aorta in 3Â min

“…These sequences offer inherent high contrast between blood and background tissues, thereby allowing for optimal delineation of the aortic lumen [ 8 , 19 ] and accurate, reproducible pre-operative monitoring of aortic root diameters [ 1 , 15 , 20 , 21 ]. However, several limitations are intrinsic to this approach [ 22 , 23 ]. Conventional 3D bSSFP CMRA techniques use diaphragmatic respiratory gating (dNAV) to minimize the effects of respiratory motion in the images, which results in unpredictable and excessively long acquisition times [ 22 ] and the risk of incomplete or aborted scans because of respiratory drift [ 23 , 24 ].…”

Natively fat‐suppressed 5D whole‐heart MRI with a radial free‐running fast‐interrupted steady‐state (FISS) sequence at 1.5T and 3T

“…As a reference for comparison, the average (N = 10) specific absorption rate for a triggered 3D Cartesian single‐phase coronary MRI scan at 1.5T using the protocol in ref. was 1.0 ± 0.1 W/kg. In general, a large difference in image quality was observed when comparing FISS to bSSFP (Figures ), with the former demonstrating markedly reduced streak artifact.…”