In vitro and in vivo comparison of two-, three- and four-point Dixon techniques for clinical intramuscular fat quantification at 3 T

To compare Dixon-based MRI techniques for intramuscular fat quantification at 3 T with MR spectroscopy (MRS) in vitro and in vivo. In vitro, two- three- and four-point mDixon (Philips Medical Systems, Best, Netherlands) sequences with 10°, 20° and 30° flip angles were acquired from seven test phantoms with sunflower oil-water percentages of 0-60% sunflower oil and calculated fat-water ratios compared with MRS. In vivo, two- three- and four-point mDixon sequences with 10° flip angle were acquired and compared with MRS in the vastus medialis of nine healthy volunteers (aged 30.6 ± 5.3 years; body mass index 22.2 ± 2.6). In vitro, all mDixon sequences correlated significantly with MRS (r > 0.97, p