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Chen W.,University of Alberta | Le L.H.,University of Alberta | Lou E.H.M.,University of Alberta | Lou E.H.M.,Glenrose Rehabilitation Research Center
European Spine Journal

Purpose: This study aimed to investigate the intra- and inter-observer reliability of the axial vertebral rotation (AVR) measurements of adolescent idiopathic scoliosis (AIS) using the center of lamina (COL) method on ultrasound transverse images. Methods: Three cadaver vertebrae were scanned with 42 AVR configurations by both ultrasound and radiograph. In this in vitro study, four observers measured the AVR using the COL method on ultrasound transverse images and three observers measured the AVR using the Stokes’ method on radiographs. In the in vivo study, 13 AIS subjects were recruited. Eighteen spinal curvatures were identified and 48 vertebrae were selected for the AVR measurements. Two observers performed the AVR measurements on both the ultrasound images and radiographs. All measurements were performed twice with 1 week interval apart to reduce memory bias. The intraclass correlation coefficient (ICC), mean absolute differences (MAD), and standard deviation (SD) were used to analyze the intra- and inter-observer reliability of the AVR measurements. The Bland–Altman plot was used to analyze the 95 % limit of the differences between the two methods. Results: The proposed COL method had high intra- and inter-observer reliability on both the in vitro and in vivo studies (ICCs > 0.91, MADs < 1.4°) and agreed well with the experimental setup (ICCs > 0.96, MADs < 2.3°). The COL method showed good agreement with the Stokes’ method for the in vitro study (ICC 0.84–0.85, MAD 4.5°–5.0°), while poor agreement for the in vivo study (ICC 0.49–0.54, MAD 2.7°–3.5°). Conclusions: The pilot study indicated the proposed COL method was a simple and reliable method to evaluate the AVR on ultrasound images. Standardization of the posture during ultrasound scan and taking radiograph is important. © 2016 Springer-Verlag Berlin Heidelberg Source

Vo Q.N.,University of Alberta | Vo Q.N.,Ho Chi Minh City University of Technology | Lou E.H.M.,University of Alberta | Lou E.H.M.,Glenrose Rehabilitation Research Center | Le L.H.,University of Alberta
Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS

Spinal deformity is a three-dimensional (3D) spinal disorder with a lateral deviation and coupled with axial vertebral rotation (AVR). The current clinical practice only measures its severity on postero-anterior (PA) radiographs, which may underestimate the deformity. The actual severity should be obtained on the plane of maximal curvature (PMC), which requires a 3D spinal image. There are many approaches to reconstruct 3D spinal images; however, ultrasound is one of the promising techniques with its non-ionizing characteristic. This study proposed an image processing method using the voxel-based bilinear interpolation to reconstruct a 3D spinal image from ultrasound data, from which the AVR was measured and the spinal curvature on the PMC was determined. In-vitro and in-vivo experiments were performed to determine the accuracy of the measurements from the ultrasound method. The results showed that the 3D ultrasound spinal image could be reconstructed. The curvature angle on the PA and the PMC planes could also be determined. The tilt angle of each individual vertebra in in-vitro study showed high accuracy and correlation (MAD < 0.9° ± 0.2° and r2 > 0.87) when comparing the measurements from CT with ultrasound. In in-vivo study, the curvature angles measured on the PA radiographs and ultrasound images yielded a small difference (MAD 3.4° ± 1.0°) and a strong correlation (r2 = 0.63) within a clinical accepted error of 5°. © 2015 IEEE. Source

Zheng R.,University of Alberta | Young M.,University of Alberta | Hill D.,University of Alberta | Hill D.,Glenrose Rehabilitation Research Center | And 7 more authors.

Study design. Retrospective study of the coronal curvature measurement on ultrasound (US) images with the aid of previous radiographs. Objective. To compare the reliability and accuracy of the coronal curvature measurements from US images on children who have adolescent idiopathic scoliosis (AIS) with and without the knowledge of previous radiographs. Summary of Background Data. Using US imaging technique to measure coronal curvature on children with AIS has demonstrated high intra- and interrater reliabilities. However, the selection of end-vertebrae and the measurement difference between radiography and the US method were only moderately reliable. Methods. Two raters measured the coronal curvatures from 65 AIS standing US spine images, without (measured one time) and with the aid of previous standing radiographs (measured two times). The intra- and interrater reliability, the correlation and the difference between the radiographic and US measurements, and the error index of the end-vertebrae selection were assessed. Results. Overall, 109 curves were investigated. The intraclass correlation coefficients (ICC) of intra- and interrater reliability of the US coronal curvature measurement with the aid of previous radiographs (AOR) were 0.95 and 0.91, respectively. In comparison with the radiographic measurements, the correlation of AOR method (R 2) was 0.90 and the MAD was 2.8°; the corresponding results of the US measurement without the AOR (blinded US method) were 0.73° and 4.8°, respectively. The average error index on end-vertebral selection improved 43% with the AOR. Conclusion. The AOR method significantly improved reliability and accuracy of the spinal curvature measurement on US images compared with the blinded US method (P<0.001). It indicates that US standing images with the AOR can be used as a reliable and accurate nonionizing imaging method to monitor children with AIS. © 2016 Wolters Kluwer Health, Inc. Source

Zheng R.,University of Alberta | Chan A.C.Y.,University of Alberta | Chen W.,University of Alberta | Hill D.L.,University of Alberta | And 8 more authors.
Spine Deformity

Study Design Retrospective reliability study of the coronal curvature measurement on ultrasound (US) imaging in adolescent idiopathic scoliosis (AIS). Objectives To determine the intra- and inter-rater reliability and validity of the coronal curvature measurements obtained from US images. Summary of Background Data Cobb angle measurements on radiographs are the usual method to diagnose and monitor the progression of scoliosis. Repeated ionizing radiation exposure is a frequent concern of patients and their families. Use of US imaging method to measure coronal curvature in children who have idiopathic scoliosis has not been clinically validated. Methods The researchers scanned 26 subjects using a medical 3-dimensional US system. Spinal radiographs were obtained on the same day from the local scoliosis clinic. Three raters used the center of lamina method to measure the coronal curvature on the US images twice 1 week apart. The raters also measured the Cobb angle on the radiographs twice. Intra- and inter-rater reliability of the coronal curvature measurement from the US images was analyzed using intra-class correlation coefficients. The correlation coefficient of the US coronal curvature measurements was compared with the Cobb angles. Results The intra-class correlation coefficient (2,1) values of intra- and inter-rater reliability on the US method were greater than 0.80. Standard error of measurement on both of the intra- and inter-rater US methods was less than 2.8°. The correlation coefficient between the US and radiographic methods ranged between 0.78 and 0.84 among 3 raters. Conclusions The US method illustrated substantial intra- and inter-rater reliability. The measurement difference between radiography and the US method was within the range of clinically acceptable error (5°). The US method may be considered a radiation-free alternative to assess children with scoliosis of mild to moderate severity. © 2015 Scoliosis Research Society. Source

Chalmers E.,University of Alberta | Westover L.,University of Alberta | Westover L.,Glenrose Rehabilitation Research Center | Jacob J.,Glenrose Rehabilitation Research Center | And 8 more authors.
Medical and Biological Engineering and Computing

Adolescent idiopathic scoliosis (AIS) is a three-dimensional spinal deformity. Brace treatment is a common non-surgical treatment, intended to prevent progression (worsening) of the condition during adolescence. Estimating a braced patient’s risk of progression is an essential part of planning treatment, so method for predicting this risk would be a useful decision support tool for practitioners. This work attempts to discover whether failure of brace treatment (progression) can be predicted at the start of treatment. Records were obtained for 62 AIS patients who had completed brace treatment. Subjects were labeled as “progressive” if their condition had progressed despite brace treatment and “non-progressive” otherwise. Wrapper-based feature selection selected two useful predictor variables from a list of 14 clinical measurements taken from the records. A logistic regression model was trained to classify patients as “progressive” or “non-progressive” using these two variables. The logistic regression model’s simplicity and interpretability should facilitate its clinical acceptance. The model was tested on data from an additional 28 patients and found to be 75 % accurate. This accuracy is sufficient to make the predictions clinically useful. It can be used online: http://www.ece.ualberta.ca/~dchalmer/SimpleBracePredictor.html. © 2015, International Federation for Medical and Biological Engineering. Source

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