title: Reliability of assessing the coronal curvature of children with scoliosis by using ultrasound images.
abstract: OBJECTIVE
  To investigate the intra- and inter-observer reliability of the coronal curvature asymmetry of children with adolescent idiopathic scoliosis (AIS) using the center of lamina (COL) method on ultrasound (US) images.
  
  
  METHODS
  A cadaver spinal column phantom which was manipulated to present 30 scoliotic curves of varying severity of scoliotic deformities was scanned using both the US and laser scanner (LS) systems. Three observers of varying experience and skill measured the coronal curvature using the Cobb method on the LS images and the COL method on the US images. All of the measurements were performed twice, with a 1-week interval to reduce memory bias. The intra-class correlation coefficient (ICC), the mean absolute differences (MAD), and the error index (EI) were calculated to determine the agreement on selecting the end vertebrae. In addition, five AIS subjects were scanned using the US system. One observer measured the coronal curvature on the US images twice, and the measurements were compared with the Cobb angle reported in the clinical records.
  
  
  RESULTS
  In the phantom study, the COL method showed high intra- and inter-observer reliabilities, with all ICC values >0.88. The maximum MAD of the COL measurements between different sessions among all observers was <4.1°. The EI values of the US method had similar end-vertebra selections as the LS method. The results of the pilot study showed a high intra-reliability for the US measurements. The measured difference between the Cobb and COL methods was 0.7° ± 0.5°.
  
  
  CONCLUSIONS
  The COL method using US images appears to be a very reliable method for measuring the coronal curvature in AIS without the need to expose the patient to radiation.
authors.affiliation: Department of Biomedical Engineering, University of Alberta, Edmonton, AB Canada.
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.affiliation: Department of Surgery, Glenrose Rehabilitation Research Centre, University of Alberta, 10105-112 Ave, Edmonton, AB T5G 0H1 Canada ; Alberta Health Services-Glenrose Rehabilitation Hospital, Edmonton, AB Canada.
authors.forename: Edmond H M
authors.initials: EH
authors.lastname: Lou
authors.affiliation: Alberta Health Services-Glenrose Rehabilitation Hospital, Edmonton, AB Canada.
authors.forename: Phoebe Q
authors.initials: PQ
authors.lastname: Zhang
authors.affiliation: Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton, AB Canada.
authors.forename: Lawrence H
authors.initials: LH
authors.lastname: Le
authors.affiliation: Department of Surgery, Glenrose Rehabilitation Research Centre, University of Alberta, 10105-112 Ave, Edmonton, AB T5G 0H1 Canada ; Alberta Health Services-Glenrose Rehabilitation Hospital, Edmonton, AB Canada.
authors.forename: Doug
authors.initials: D
authors.lastname: Hill
keywords: Adolescent idiopathic scoliosis; Center of lamina method; Coronal curvature; Reliability; Ultrasound image