title: Myocardial fat quantification in humans: Evaluation by two-point water-fat imaging and localized proton spectroscopy.
abstract: Proton MR spectroscopy ((1)H-MRS) has been used for in vivo quantification of intracellular triglycerides within the sarcolemma. The purpose of this study was to assess whether breath-hold dual-echo in- and out-of-phase MRI at 3.0 T can quantify the fat content of the myocardium. Biases, including T(1), T*(2), and noise, that confound the calculation of the fat fraction were carefully corrected. Thirty-four of 46 participants had both MRI and MRS data. The fat fractions from MRI showed a strong correlation with fat fractions from MRS (r = 0.78; P < 0.05). The mean myocardial fat fraction for all 34 subjects was 0.7 +/- 0.5% (range: 0.11-3%) assessed with MRS and 1.04 +/- 0.4% (range: 0.32-2.44%) assessed with in- and out-of-phase MRI (P < 0.05). Scanning times were less than 15 sec for Dixon imaging, plus an additional minute for the acquisition used for T*(2) calculation, and 15-20 min for MRS. The average postprocessing time for MRS was 3 min and 5 min for MRI including T*(2) measurement. We conclude that the dual echo method provides a rapid means to detect and quantifying myocardial fat content in vivo. Correction/adjustment for field inhomogeneity using three or more echoes seems crucial for the dual echo approach.
authors.affiliation: Department of Radiology, Johns Hopkins Hospital, Baltimore, Maryland, USA. cliu51@jhmi.edu
authors.forename: Chia-Ying
authors.initials: CY
authors.lastname: Liu
authors.forename: Alban
authors.initials: A
authors.lastname: Redheuil
authors.forename: Ronald
authors.initials: R
authors.lastname: Ouwerkerk
authors.forename: Joao A C
authors.initials: JA
authors.lastname: Lima
authors.forename: David A
authors.initials: DA
authors.lastname: Bluemke
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology*; D000328:Adult; D000368:Aged; D000465:Algorithms; D001834:Body Water; D055424:Cardiac-Gated Imaging Techniques / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009206:Myocardium; D011522:Protons; D012815:Signal Processing, Computer-Assisted
chemical_list: D011522:Protons