Imaging sequence for joint myocardial T 1 mapping and fat/water separation

• Published in: Magnetic resonance in medicine Vol. 81; no. 1; pp. 486 - 494
• Main Authors: Nezafat, Maryam, Nakamori, Shiro, Basha, Tamer A., Fahmy, Ahmed S., Hauser, Thomas, Botnar, René M.
• Format: Journal Article
• Language: English
• Published: United States John Wiley and Sons Inc 01.01.2019
• Subjects: Adipose Tissue - diagnostic imaging; Adult; Aged; Algorithms; Atrial Fibrillation - diagnostic imaging; Cardiac Imaging Techniques; Cardiomyopathies - diagnostic imaging; Female; Healthy Volunteers; Heart - diagnostic imaging; Heart - physiopathology; Humans; Hypertrophy, Left Ventricular - diagnostic imaging; Magnetic Resonance Imaging; Male; Middle Aged; Myocardium - pathology; Notes—Imaging Methodology; Pericardium - diagnostic imaging; Phantoms, Imaging; Prospective Studies; Reproducibility of Results; Water; Young Adult; myocardial tissue characterization; cardiac magnetic resonance imaging; Dixon; T1 mapping
• ISSN: 0740-3194; 1522-2594
• DOI: 10.1002/mrm.27390

To develop and evaluate an imaging sequence to simultaneously quantify the epicardial fat volume and myocardial T relaxation time. We introduced a novel simultaneous myocardial T mapping and fat/water separation sequence (joint T -fat/water separation). Dixon reconstruction is performed on a dual-echo data set to generate water/fat images. T maps are computed using the water images, whereas the epicardial fat volume is calculated from the fat images. A phantom experiment using vials with different T /T values and a bottle of oil was performed. Additional phantom experiment using vials of mixed fat/water was performed to show the potential of this sequence to mitigate the effect of intravoxel fat on estimated T maps. In vivo evaluation was performed in 17 subjects. Epicardial fat volume, native myocardial T measurements and precision were compared among slice-interleaved T mapping, Dixon, and the proposed sequence. In the first phantom, the proposed sequence separated oil from water vials and there were no differences in T of the fat-free vials (P = .1). In the second phantom, the T error decreased from 22%, 36%, 57%, and 73% to 8%, 9%, 16%, and 26%, respectively. In vivo there was no difference between myocardial T values (1067 ± 17 ms versus 1077 ± 24 ms, P = .6). The epicardial fat volume was similar for both sequences (54.3 ± 33 cm versus 52.4 ± 32 cm , P = .8). The proposed sequence provides simultaneous quantification of native myocardial T and epicardial fat volume. This will eliminate the need for an additional sequence in the cardiac imaging protocol if both measurements are clinically indicated.