Reliability and accuracy of scoliotic parameters on using a wireless handheld 3D ultrasound for children with adolescent idiopathic scoliosis: a pilot study

PurposeTo report the accuracy and reliability of Cobb angle (CA), axial vertebral rotation (AVR), kyphotic and lordotic angles (KA and LA) measurements on using a new 3D ultrasound (US) system.MethodsForty participants (34 F, 6 M, aged 14.0 +/- 2.3 years) were recruited. The first 20 participants were scanned by the validated US system and the new US system. The other 20 participants were scanned with the new US system only. Two raters (R1 and R2) performed the measurements: R1 has 10 years of experience in radiology but is new in ultrasound scoliosis, while R2 has 30 years of scoliosis experience. All US images were measured twice by R1, and once by R2. Forty posteroanterior and 30 lateral standing radiographs were obtained and measured once by R1. Statistical analysis consisted of mean absolute difference (MAD), intraclass correlation coefficient (ICC (2,1)), and Bland-Altman plots.ResultsR1 showed excellent intra-rater and inter-rater reliability for US measurements with ICCs(2,1) >= 0.91. The inter-method reliability was good between the two US systems for all parameters with ICCs(2,1) >= 0.85 and maximum MAD of 3.4 degrees. The new US showed good reliability and accuracy compared to radiographs for CA, AVR and KA with ICCs(2,1) >= 0.81 and maximum MAD of 5.8 degrees, but poor results for LA with ICCs(2,1) of 0.27-0.35 and MADs of 14.0 degrees-15.4 degrees.ConclusionThe new 3D US system showed good reliability and accuracy for CA, AVR and KA measurements, but a large measurement discrepancy on LA. A new measurement method for US LA may need to investigate.