Aorta and coronary artery assessment using high-contrast respiratory motion corrected and ECG-gated 3D T2-prepared GRE MRI with Dixon fat-water separation in patients with and without prior aortic root surgery at 3 T

Abstract

Objectives: Magnetic resonance imaging (MRI) is a widely utilized, non-invasive imaging modality for evaluating aortic diseases. In this study, we sought to validate a novel, ECG-gated, non-contrast enhanced cardiovascular magnetic resonance sequence (T2-Prepared GRE and Dixon Water-Fat Separation, T2p GD) in patients with aortic disease – both with and without prior aortic surgery – and to compare its diagnostic performance with that of standard contrast-enhanced MR angiography (CE-MRA). Materials and methods: A total of 55 patients undergoing cardiovascular MRI were recruited, including 26 with and 29 without a history of aortic surgery. The signal-to-noise ratio (SNR) was measured in the aorta, pericardial fat, and myocardial septum, while the contrast-to-noise ratios (CNR) between the aorta and septum, and the aorta and fat, were calculated for both imaging methods, stratified by surgical history. Additionally, diameters of the aorta and coronary arteries were assessed. The diagnostic quality of the images was evaluated using a five-point Likert scale. Results: While the SNR in the aorta was comparable between sequences, the new sequence provided higher SNR in both the septum and pericardial fat, as well as a significant increase in the aorta-to-fat CNR. Prior aortic surgery did not affect SNR or CNR values overall; however, in the water-only images of the new sequence, CNR between the aorta and fat was significantly lower in patients with prior surgery. Vascular diameters measured with the T2p GD sequence were consistently larger, as CE-MRA only assesses the endoluminal borders, while the T2p GD sequence includes anatomic delineation of the vessel wall. Qualitative image assessment revealed that the new sequence achieved higher overall quality ratings and superior subjective delineation, enabling more accurate measurement of the aortic sinus and the proximal third of the coronary arteries across all readers. Conclusions: The novel T2p GD sequence enables detailed anatomic characterization of the aorta and coronary arteries and a higher CNR than conventional CE-MRA, even in patients with a history of aortic surgery.