title: Assessment of gluteus maximus muscle area with different image analysis programs.
abstract: OBJECTIVE
  To determine the effectiveness of a percutaneous gluteal stimulation system (GSTIM) by comparing assessments of axial computed tomography (CT) scans for the pelvic area.
  
  
  METHODS
  Comparing the measurements of the cross-sectional area (CSA) of the gluteus maximus muscle between raters and 2 image analysis programs.
  
  
  METHODS
  Retrospective axial CT scans of the pelvic area.
  
  
  METHODS
  Men (N=9) with complete (below T6) spinal cord injury (SCI) and at least 2 years postinjury participated in the study (range, 29-75y; mean age, 51.8y).
  
  
  METHODS
  Comparing gluteus maximus CSA before and after a period of GSTIM.
  
  
  METHODS
  Measurements made by 2 expert and 2 nonexpert raters were used to compare the repeatability and reliability of measuring muscle CSA. The longitudinal study presented is from repeated CT scans obtained over a 2-year period for 1 representative participant who received a GSTIM system.
  
  
  RESULTS
  For repeatability, nonexpert raters measured a mean CSA of 35.2 cm2 (range, 20-45 cm2), while experts measured 21 cm2 (range, 10-35 cm2). A composite of all raters using the same program had SDs of 2.5 to 2.6 cm2 for a program available through the National Institutes of Health and 2.5 to 4.4 cm2 for a commercially available program. For reliability, differences between the 2 programs had mean differences in SD between 2.2 and 3.7 cm2.
  
  
  CONCLUSIONS
  The same rater and program (preferably the more reliable ImageJ) is recommended for the course of a longitudinal study. Otherwise, significant error would be introduced. Furthermore, significant increases in the CSA of gluteal muscle compared with preintervention (baseline) measurements were observed for the participant receiving GSTIM.
authors.affiliation: Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA.
authors.forename: Gary A
authors.initials: GA
authors.lastname: Wu
authors.forename: Kath
authors.initials: K
authors.lastname: Bogie
mesh_terms: D000328:Adult; D000368:Aged; D002081:Buttocks; D004599:Electric Stimulation Therapy / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging*; D009133:Muscular Atrophy / Q000000981:diagnostic imaging / Q000209:etiology / Q000534:rehabilitation*; D015588:Observer Variation; D010388:Pelvis; D015203:Reproducibility of Results; D013119:Spinal Cord Injuries / Q000150:complications; D014057:Tomography, X-Ray Computed