title: Assessment of follow-up sonography and clinical improvement among infants with congenital muscular torticollis.
abstract: OBJECTIVE
  Infants grow rapidly, which causes the SCM to thicken physiologically. Therefore some cases of physiologically-thickened SCM can be confused with a poor response to physical therapy. There have been only a few quantitative ultrasonographic studies on the clinical outcome of rehabilitation for CMT. Our aim was to evaluate whether a new sonographic assessment method that uses the muscular thickness ratio of the SCM can help quantify the outcome of rehabilitation therapy for patients with CMT.
  
  
  METHODS
  We evaluated 48 patients (male/female, 17:31; mean age, 3.9 months) who were diagnosed with CMT and who underwent initial and follow-up sonography. The ratio of the thickness of the involved SCM to the thickness of the intact SCM (SCM thickness ratio) was calculated. A scoring system based on the range of motion of the neck was used to assess clinical improvement. The correlations between clinical improvement and the thickness of the involved muscle, the difference in involved muscle thickness, the SCM thickness ratio, and the difference in the SCM thickness ratio were evaluated with Spearman rank correlations.
  
  
  RESULTS
  Follow-up Cheng scores were higher than initial scores; this difference indicates clinical resolution (follow-up, 4.90; initial, 3.38). The SCM thickness ratio at follow-up was lower than that at the initial evaluation (follow-up, 1.29-1.34; initial, 1.65-1.77). Intra- and interobserver agreements were excellent. Most variables were moderately correlated with clinical improvement (correlation coefficients, 0.36-0.509). R1 showed the highest correlation with clinical improvement (0.481 and 0.509), followed by the initial maximal thickness of the SCM (0.434 and 0.488). ΔP (P1-P2) and ΔR showed similar correlation coefficients with clinical improvement.
  
  
  CONCLUSIONS
  Measurement of the SCM thickness ratio appears to overcome the problem of a false-positive diagnosis of clinical aggravation of CMT resulting from physiologic growth. R1 and ΔR are accurate objective measurements, which can be used in the management of CMT.
authors.affiliation: Department of Radiology, Sungkyunkwan University School of Medicine, Kangbuk Samsung Hospital, Seoul, Republic of Korea.
authors.forename: H-J
authors.initials: HJ
authors.lastname: Park
authors.forename: S S
authors.initials: SS
authors.lastname: Kim
authors.forename: S-Y
authors.initials: SY
authors.lastname: Lee
authors.forename: Y-T
authors.initials: YT
authors.lastname: Lee
authors.forename: K
authors.initials: K
authors.lastname: Yoon
authors.forename: E-C
authors.initials: EC
authors.lastname: Chung
authors.forename: M-H
authors.initials: MH
authors.lastname: Rho
authors.forename: H-J
authors.initials: HJ
authors.lastname: Kwag
mesh_terms: D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008297:Male; D009333:Neck / Q000000981:diagnostic imaging / Q000502:physiology; D009334:Neck Muscles / Q000000981:diagnostic imaging* / Q000502:physiology; D026741:Physical Therapy Modalities; D016059:Range of Motion, Articular; D012189:Retrospective Studies; D012720:Severity of Illness Index; D014103:Torticollis / Q000151:congenital* / Q000000981:diagnostic imaging / Q000534:rehabilitation; D014463:Ultrasonography / Q000379:methods*