title: Reliability of MR-Based Volumetric 3-D Analysis of Pelvic Muscles among Subjects with Low Back with Leg Pain and Healthy Volunteers.
abstract: OBJECTIVE
  Lately, the diagnostic value of magnetic resonance imaging, Lasègue sign and classic neurological signs have been considered not accurate enough to distinguish the radicular from non-radicular low back with leg pain (LBLP) and a calculation of the symptomatic side muscle volume has been indicated as a probable valuable marker. However, only the multifidus muscle volume has been calculated so far. The main objective of the study was to verify whether LBLP subjects presented symptomatic side pelvic muscle atrophy compared to healthy volunteers. The second aim was to assess the inter-rater reliability of 3-D manual method for segmenting and measuring the volume of the gluteus maximus, gluteus medius, gluteus minimus and piriformis muscles in both LBLP patients and healthy subjects.
  
  
  METHODS
  Two independent raters analyzed MR images of LBLP and healthy subjects towards muscle volume of four pelvic muscles, i.e. the piriformis, gluteus minimus, gluteus medius and gluteus maximus. For both sides, the MR images of the muscles without adipose tissue infiltration were manually segmented in 3-D medical images.
  
  
  RESULTS
  Symptomatic muscle atrophy was confirmed in only over 50% of LBLP subjects (gluteus maximus (p<0.001), gluteus minimus (p<0.01) and piriformis (p<0.05)). The ICC values indicated that the inter-rater reproducibility was greater than 0.90 for all measurements (LBLP and healthy subjects), except for the measurement of the right gluteus medius muscle in LBLP patients, which was equal to 0.848.
  
  
  CONCLUSIONS
  More than 50% of LBLP subjects presented symptomatic gluteus maximus, gluteus minimus and piriformis muscle atrophy. 3-D manual segmentation reliably measured muscle volume in all the measured pelvic muscles in both healthy and LBLP subjects. To answer the question of what kind of muscle atrophy is indicative of radicular or non-radicular pain further studies are required.
authors.affiliation: Department of Rheumatology and Rehabilitation, Poznan University of Medical Sciences, Poznan, Poland.
authors.forename: Elżbieta
authors.initials: E
authors.lastname: Skorupska
authors.affiliation: Department of Rheumatology and Rehabilitation, Poznan University of Medical Sciences, Poznan, Poland.
authors.forename: Przemysław
authors.initials: P
authors.lastname: Keczmer
authors.affiliation: Department of Mathematics and Mathematical Economics, Warsaw School of Economics, Warsaw, Poland.
authors.forename: Rafał M
authors.initials: RM
authors.lastname: Łochowski
authors.affiliation: Department of Rheumatology and Rehabilitation, Poznan University of Medical Sciences, Poznan, Poland.
authors.forename: Paulina
authors.initials: P
authors.lastname: Tomal
authors.affiliation: Department of Virtual Engineering, Poznan University of Technology, Poznan, Poland.
authors.forename: Michał
authors.initials: M
authors.lastname: Rychlik
authors.affiliation: Department of Rheumatology and Rehabilitation, Poznan University of Medical Sciences, Poznan, Poland.
authors.forename: Włodzimierz
authors.initials: W
authors.lastname: Samborski
mesh_terms: D016022:Case-Control Studies; D006801:Humans; D021621:Imaging, Three-Dimensional; D007866:Leg; D017116:Low Back Pain / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging; D018482:Muscle, Skeletal / Q000473:pathology* / Q000503:physiopathology*; D009460:Neurologic Examination; D009929:Organ Size; D010388:Pelvis / Q000473:pathology*; D015203:Reproducibility of Results