title: Analysis of MRI signal changes in the adjacent pedicle of adolescent patients with fresh lumbar spondylolysis.
abstract: OBJECTIVE
  The purpose of this study is to investigate a discrepancy between MRI and computed tomography (CT) findings in the spinal level distribution of spondylolysis. Recent advances in MRI have led to the early diagnosis of spondylolysis. Therefore, bony healing can be expected before the condition has a chance to worsen. In this study, we used MRI to examine the changes in spinal level signals in the pedicles adjacent to the pars interarticularis in adolescents with fresh lumbar spondylolysis. We then compared spinal level distribution of spondylolysis with that of previous results obtained by multidetector CT.
  
  
  METHODS
  The study included 98 adolescent patients (31 women and 67 men; mean age, 13.6 years; age range, 9-18 years) with fresh lumbar spondylolysis who showed MRI signal changes in the adjacent pedicle. An MRI signal change was defined as a high signal change on fat-suppressed imaging.
  
  
  RESULTS
  MRI signal changes were detected in 150 adjacent pedicles of 101 vertebrae. Of these vertebrae, MRI signal changes in only 67 (66.3%) corresponded to L5, while changes in 34 (33.7%) corresponded to L3 or L4. In our follow-up study, the bone-healing rate with no vertebral defect was 100% at L3, 97.1% at L4, and 84.4% at L5. In addition, 11 of 34 (32.4%) vertebrae with signal changes at L3 or L4 occurred with L5 terminal-stage spondylolysis (no MRI signal change).
  
  
  CONCLUSIONS
  MRI revealed a higher prevalence of L3 or L4 spondylolysis than observed with CT.
authors.affiliation: Department of Orthopedics, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima, 770-8503, Japan, ygoda2000@yahoo.co.jp.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Goda
authors.forename: Toshinori
authors.initials: T
authors.lastname: Sakai
authors.forename: Tadanori
authors.initials: T
authors.lastname: Sakamaki
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Takata
authors.forename: Kosaku
authors.initials: K
authors.lastname: Higashino
authors.forename: Koichi
authors.initials: K
authors.lastname: Sairyo
mesh_terms: D000273:Adipose Tissue / Q000000981:diagnostic imaging / Q000473:pathology; D000293:Adolescent; D002648:Child; D042241:Early Diagnosis; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D017116:Low Back Pain / Q000000981:diagnostic imaging / Q000473:pathology; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging* / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D061330:Multidetector Computed Tomography / Q000379:methods*; D012680:Sensitivity and Specificity; D013169:Spondylolysis / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000628:therapy