A reliability and validity study for Scolioscan: a radiation-free scoliosis assessment system using 3D ultrasound imaging

Abstract

BackgroundRadiographic evaluation for patients with scoliosis using Cobb method is the current gold standard, but radiography has radiation hazards. Several groups have recently demonstrated the feasibility of using 3D ultrasound for the evaluation of scoliosis. Ultrasound imaging is radiation-free, comparatively more accessible, and inexpensive. However, a reliable and valid 3D ultrasound system ready for clinical scoliosis assessment has not yet been reported. Scolioscan is a newly developed system targeted for scoliosis assessment in clinics by using coronal images of spine generated by a 3D ultrasound volume projection imaging method. The aim of this study is to test the reliability of spine deformity measurement of Scolioscan and its validity compared to the gold standard Cobb angle measurements from radiography in adolescent idiopathic scoliosis (AIS) patients.MethodsProspective study divided into two stages: 1) Investigation of intra- and inter- reliability between two operators for acquiring images using Scolioscan and among three raters for measuring spinal curves from those images; 2) Correlation between the Cobb angle obtained from radiography by a medical doctor and the spine curve angle obtained using Scolioscan (Scolioscan angle). The raters for ultrasound images and the doctors for evaluating radiographic images were mutually blinded. The two stages of tests involved 20 (80 % females, total of 26 angles, age of 16.4 ± 2.7 years, and Cobb angle of 27.6 ± 11.8°) and 49 (69 % female, 73 angles, 15.8 ± 2.7 years and 24.8 ± 9.7°) AIS patients, respectively. Intra-class correlation coefficients (ICC) and Bland-Altman plots and root-mean-square differences (RMS) were employed to determine correlations, which interpreted based on defined criteria.ResultsWe demonstrated a very good intra-rater and intra-operator reliability for Scolioscan angle measurement with ICC larger than 0.94 and 0.88, respectively. Very good inter-rater and inter-operator reliability was also demonstrated, with both ICC larger than 0.87. For the thoracic deformity measurement, the RMS were 2.5 and 3.3° in the intra- and inter-operator tests, and 1.5 and 3.6° in the intra- and inter-rater tests, respectively. The RMS differences were 3.1, 3.1, 1.6, 3.7° in the intra- and inter-operator and intra- and inter-rater tests, respectively, for the lumbar angle measurement. Moderate to strong correlations (R2 > 0.72) were observed between the Scolioscan angles and Cobb angles for both the thoracic and lumbar regions. It was noted that the Scolioscan angle slightly underestimated the spinal deformity in comparison with Cobb angle, and an overall regression equation y = 1.1797x (R2 = 0.76) could be used to translate the Scolioscan angle (x) to Cobb angle (y) for this group of patients. The RMS difference between Scolioscan angle and Cobb angle was 4.7 and 6.2°, with and without the correlation using the overall regression equation.ConclusionsWe showed that Scolioscan is reliable for measuring coronal deformity for patients with AIS and appears ...

Postural Screening for Adolescent Idiopathic Scoliosis with Infrared Thermography

“…Therefore, further studies are required to determine the exact duration for SSS. Furthermore, the gold standard for diagnosing scoliosis is radiography, rather than Scolioscan, which is a tool used to provide the spinal deformity angle of the participants, despite the demonstration by the development team of Scolioscan showing that the scanner has good reliability and close correlations with radiography 32 – 34 .…”

Results of ultrasound-assisted brace casting for adolescent idiopathic scoliosis

“…Although finite element (FE) models have been developed to determine optimal orientations and load magnitudes of pressure pads for brace design [ 18 , 19 ], these still have practical limitations [ 20 ] with evaluation of the brace correction not available until the in-brace follow-up clinic. Recently, ultrasound (US) imaging, a real-time non-invasive and non-ionizing method, was demonstrated to be successful in measuring proxy Cobb angles, vertebral rotation, and flexibility [ 21 – 27 ]. The proxy Cobb angles which use vertebrae lamina positions rather than end plates, measured from ultrasound images have high intra- and inter-reliability as well as correlate well with radiographic measurements [ 22 , 26 ].…”

Weight-bearing Imaging in Adolescent Idiopathic Scoliosis

“…This system was found to be reliable with a high degree of accuracy for measuring coronal deformities for AIS subjects in the upright position with full weight-bearing (intra-rater and intra-operator rates: > 0.94 and > 0.88, respectively). 48 Similarly, Brink et al 49 evaluated the reliability and validity of 3D ultrasound for different coronal angles in AIS subjects and found an excellent correlation between the ultrasound and Cobb angle measurements (radiography approach) (►Fig. 5).…”

“…In tandem with these advantages, several studies have explored the applicability and reliability of this imaging technique in AIS management. Zheng et al 48 developed a 3D ultrasound system dubbed "Scolioscan Air." This system was found to be reliable with a high degree of accuracy for measuring coronal deformities for AIS subjects in the upright position with full weight-bearing (intra-rater and intra-operator rates: > 0.94 and > 0.88, respectively).…”