Reliability of assessing the coronal curvature of children with scoliosis by using ultrasound images

Wei Chen,Edmond H M Lou,Doug Hill,Phoebe Q Zhang,Lawrence H Le

doi:10.1007/s11832-013-0539-y

Wei Chen, Edmond H M Lou + Show 3 more

Open Access

https://doi.org/10.1007/s11832-013-0539-y

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Abstract

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. 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. 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°. 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.

Highlights

Adolescent idiopathic scoliosis (AIS) is a three-dimensional (3D) spinal deformity that is first detected during adolescence with no known causes
The center of lamina (COL) method using US images appears to be a very reliable method for measuring the coronal curvature in adolescent idiopathic scoliosis (AIS) without the need to expose the patient to radiation
This result implied that the Cobb angle measured from the laser scanner (LS) images would be similar to that measured from the radiographs

Summary

Introduction

Adolescent idiopathic scoliosis (AIS) is a three-dimensional (3D) spinal deformity that is first detected during adolescence with no known causes. The Cobb angle [1] measured from the standing posteroanterior (PA) radiograph is the standard method to evaluate the severity of scoliosis. Many studies have focused on the accuracy and intra- and interobserver reliabilities of the Cobb angle measurement, with. Computer-aided methods have been developed to reduce the measurement variability and error of the Cobb angle measurements [10,11,12]. The results of these studies indicate that computer-aided measurements have the ability to decrease the variability by minimizing the subjective factors, such as selection of end-vertebrae and skill level of the observer. Since the reliability and accuracy of any measurement is important in the clinical decision-making process, any new proposed method to assess the severity of the scoliotic spine must be evaluated before clinical acceptance can even be contemplated

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