title: Fatty degeneration of multifidus muscle in patients with chronic low back pain and in asymptomatic volunteers: quantification with chemical shift magnetic resonance imaging.
abstract: OBJECTIVE
  To evaluate and compare the fatty degeneration of multifidus muscles by chemical shift magnetic resonance imaging (MRI) in patients with chronic low back pain and in asymptomatic volunteers.
  
  
  METHODS
  Sixty-five patients with lumbar disc pathology were selected prospectively for this study. The control group consisted of 25 asymptomatic volunteers. The patients were grouped according to the fatty degeneration of multifidus muscles by a semiquantitative method (grade 0-4) on axial T2 weighted imaging. Chemical shift MRI was performed in the axial plane using a double-echo fast low-angle shot (FLASH) sequence. Fatty degeneration was calculated through signal intensity suppression rate (SISR) and signal intensity index (SII).
  
  
  RESULTS
  The semiquantitative grading of fatty degeneration of the multifidus muscle was 0 in 25 of 65 patients (patient group 0), 1 in 20 patients (patient group 1), 2 in 20 patients (patient group 2). Neither grade 3 nor grade 4 were detected in patient groups. For the control group, patient group 0, patient group 1, and patient group 2, median SISR values were 5.00, -9.00, -17.50, and -22.50 %, respectively. SII median values were -4.20 % for the control group, 7.00 % for patient group 0, 12.50 % for patient group 1, and 19.50 % for patient group 2. SISR values in the multifidus muscle calculated for the patient groups were significantly lower than those calculated for the control group. SII values in patients groups were significantly higher than in the control group.
  
  
  CONCLUSIONS
  Chemical shift MRI may be a useful method to quantitatively evaluate the fatty degeneration in multifidus muscle in patients with low back pain.
authors.affiliation: Department of Radiology, Balikesir University, School of Medicine, Balikesir, Turkey. bhrynk@gmail.com
authors.forename: Bahar
authors.initials: B
authors.lastname: Yanik
authors.forename: Bahri
authors.initials: B
authors.lastname: Keyik
authors.forename: Isik
authors.initials: I
authors.lastname: Conkbayir
mesh_terms: D000273:Adipose Tissue / Q000473:pathology*; D000328:Adult; D001415:Back; D059350:Chronic Pain / Q000209:etiology / Q000473:pathology*; D005260:Female; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000150:complications / Q000473:pathology*; D017116:Low Back Pain / Q000209:etiology / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000473:pathology*; D009135:Muscular Diseases / Q000209:etiology / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity