title: Measurement of muscle and fat in postmenopausal women: precision of previously reported pQCT imaging methods.
abstract: Peripheral quantitative computed tomography (pQCT) imaging has been used to quantify muscle area and density as well as intermuscular adipose tissue (IMAT) and subcutaneous adipose tissue (SAT) area in the lower and upper limb. Numerous protocols have been reported to derive these soft-tissue outcomes, but their precision has not been assessed in community-dwelling postmenopausal women. The objective of this study was to compare the precision of previously reported analysis protocols for quantifying muscle area and density, as well as IMAT and SAT area in postmenopausal women. Six image analysis protocols using two available software suites (Stratec XCT, BoneJ) were identified from the pQCT literature. Analysis protocols were applied to a sample of 35 older female adults (mean age 73.7; SD 7.2 years), randomly selected from a population based-cohort and scanned twice within an average of 9.7 (SD 3.6) days. Relative precision was calculated as absolute values and as a percentage of the sample mean (root mean square coefficient of variation; CV%RMS). Soft-tissue outcomes across protocols were compared on their log-transformed coefficients of variation using multilevel linear models and Tukey contrasts. For most protocols, CV%RMS for muscle area, density, and SAT area ranged between 2.1 and 3.7%, 0.7 and 1.9%, and 2.4 and 6.4%, respectively. Precision for IMAT area varied considerably, from 3 to 42%. Consideration of these study results will aid in the selection of appropriate image analysis protocols for pQCT-derived soft-tissue outcomes in postmenopausal women.
authors: College of Kinesiology, University of Saskatchewan, Saskatoon, SK, Canada. Electronic address: andrew.frank-wilson@usask.ca.
authors: Andrew W
authors: AW
authors: Frank-Wilson
authors: Department of Mechanical Engineering, University of Saskatchewan, Saskatoon, SK, Canada.
authors: James D
authors: JD
authors: Johnston
authors: College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada; Saskatoon Osteoporosis and CaMos Centre, Saskatoon, SK, Canada.
authors: Wojciech P
authors: WP
authors: Olszynski
authors: College of Kinesiology, University of Saskatchewan, Saskatoon, SK, Canada.
authors: Saija A
authors: SA
authors: Kontulainen
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008875:Middle Aged; D009132:Muscles / Q000000981:diagnostic imaging*; D017698:Postmenopause; D050151:Subcutaneous Fat / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: BoneJ; Image analysis; Muscle adiposity; Myosteatosis; Older adults