title: Significance of magnetic resonance imaging signal change in the pedicle in the management of pediatric lumbar spondylolysis.
abstract: METHODS
  Prospective study.
  
  
  OBJECTIVE
  To investigate the time course of signal changes in the adjacent pedicle in fresh pediatric lumbar spondylolysis.
  
  
  BACKGROUND
  A recent study reported that high signal change (HSC) on T2-magnetic resonance image (MRI) in the pedicle adjacent to the pars interarticularis could be an indicator of early spondylolysis. In addition, the HSC-positive pars defects showed significant better bony healing than the HSC-negative pars defects. However, there has been no report on the time course and the duration of HSC.
  
  
  METHODS
  We prospectively investigated 10 boys and 5 girls with fresh lumbar spondylolysis showing HSC in the adjacent pedicle. Their mean age was 15.1 years, ranging from 10 to 17 years. Two patients had multilevel unilateral spondylolysis. Among 15 patients, HSC was found in 22 (12 unilateral and 5 bilateral) pedicles. At the first presentation, the diagnosis of spondylolysis was made based on the plain radiograph findings, multidetector computed tomograms (CTs), and MRI. Every month from the first presentation, follow-up MRIs were taken. When HSC disappeared, multidetector CT was taken to confirm bony healing of the pars defect.
  
  
  RESULTS
  Bony healing of the pars was obtained in 21 out of 22 defects. The bony healing rate was 95.6%. In 19 pedicles of 12 patients, HSC gradually diminished by every month until it disappeared 3 months later, and radiologic osseous healing was confirmed by CT in all but 1 patient. In the 3 remaining pedicles of 3 patients, HSC took more than 4 months to disappear.
  
  
  CONCLUSIONS
  In this study, HSC disappeared in most pedicles on the 3-month follow-up MRI. In patients who did not comply with treatment, HSC tended to last longer. These results led us to hypothesize that MRI at the third month during follow-up can indicate whether the conservative treatment is being successful or not.
authors.affiliation: Department of Orthopedics, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan. norinori@clin.med.tokushima-u.ac.jp
authors.forename: Toshinori
authors.initials: T
authors.lastname: Sakai
authors.forename: Koichi
authors.initials: K
authors.lastname: Sairyo
authors.forename: Seiichi
authors.initials: S
authors.lastname: Mima
authors.forename: Natsuo
authors.initials: N
authors.lastname: Yasui
mesh_terms: D000293:Adolescent; D001265:Athletic Injuries / Q000628:therapy; D001490:Basketball / Q000293:injuries; D001915:Braces; D002648:Child; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging; D008297:Male; D011446:Prospective Studies; D013169:Spondylolysis / Q000175:diagnosis* / Q000628:therapy; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014945:Wound Healing