title: Reliability and agreement of adipose tissue fat fraction measurements with water-fat MRI in patients with manifest cardiovascular disease.
abstract: The supraclavicular fat depot is known for brown adipose tissue presence. To unravel adipose tissue physiology and metabolism, high quality and reproducible imaging is required. In this study we quantified the reliability and agreement of MRI fat fraction measurements in supraclavicular and subcutaneous adipose tissue of 25 adult patients with clinically manifest cardiovascular disease. MRI fat fraction measurements were made under ambient temperature conditions using a vendor supplied mDixon chemical-shift water-fat multi-echo pulse sequence at 1.5 T field strength. Supraclavicular fat fraction reliability (intraclass correlation coefficientagreement , ICCagreement ) was 0.97 for test-retest, 0.95 for intra-observer and 0.56 for inter-observer measurements, which increased to 0.88 when ICCconsistency was estimated. Supraclavicular fat fraction agreement displayed mean differences of 0.5% (limit of agreement (LoA) -1.7 to 2.6) for test-retest, -0.5% (LoA -2.9 to 2.0) for intra-observer and 5.6% (LoA 0.4 to 10.8) for inter-observer measurements. Median fat fraction in supraclavicular adipose tissue was 82.5% (interquartile range (IQR) 78.6-84.0) and 89.7% (IQR 87.2-91.5) in subcutaneous adipose tissue (p < 0.0001). In conclusion, water-fat MRI has good reliability and agreement to measure adipose tissue fat fraction in patients with manifest cardiovascular disease. These findings enable research on determinants of fat fraction and enable longitudinal monitoring of fat fraction within adipose tissue depots. Interestingly, even in adult patients with manifest cardiovascular disease, supraclavicular adipose tissue has a lower fat fraction compared with subcutaneous adipose tissue, suggestive of distinct morphologic characteristics, such as brown adipose tissue.
authors.affiliation: Department of Vascular Medicine, University Medical Center Utrecht, The Netherlands.
authors.forename: Bas T
authors.initials: BT
authors.lastname: Franssens
authors.affiliation: Department of Radiology, University Medical Center Utrecht, The Netherlands.
authors.forename: Anouk L
authors.initials: AL
authors.lastname: Eikendal
authors.affiliation: Department of Radiology, University Medical Center Utrecht, The Netherlands.
authors.forename: Tim
authors.initials: T
authors.lastname: Leiner
authors.affiliation: Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, The Netherlands.
authors.forename: Yolanda
authors.initials: Y
authors.lastname: van der Graaf
authors.affiliation: Department of Vascular Medicine, University Medical Center Utrecht, The Netherlands.
authors.forename: Frank L J
authors.initials: FL
authors.lastname: Visseren
authors.affiliation: Department of Radiology, University Medical Center Utrecht, The Netherlands.
authors.forename: J M
authors.initials: JM
authors.lastname: Hoogduin
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism*; D000368:Aged; D002318:Cardiovascular Diseases / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D015203:Reproducibility of Results
keywords: agreement; brown adipose tissue; fat fraction; mDixon MRI; reliability; reproducibility