Semi-automatic ultrasound curve angle measurement for adolescent idiopathic scoliosis

• Published in: Spine deformity Vol. 10; no. 2; pp. 351 - 359
• Main Authors: Yang, De, Lee, Timothy Tin-Yan, Lai, Kelly Ka-Lee, Lam, Tsz-Ping, Chu, Winnie Chiu-Wing, Castelein, René Marten, Cheng, Jack Chun-Yiu, Zheng, Yong-Ping
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.03.2022
• Subjects: Adolescent; Case Series; Humans; Kyphosis; Medicine; Medicine & Public Health; Orthopedics; Reproducibility of Results; Scoliosis - diagnostic imaging; Thoracic Vertebrae - diagnostic imaging; Ultrasonography - methods; Scoliotic angles; Transverse process; AIS; Cobb; 3D ultrasound
• ISSN: 2212-134X; 2212-1358; 2212-1358
• DOI: 10.1007/s43390-021-00421-4

Purpose Using X-ray to evaluate adolescent idiopathic scoliosis (AIS) conditions is the clinical gold standard, with potential radiation hazards. 3D ultrasound has demonstrated its validity and reliability of estimating X-ray Cobb angle (XCA) using spinous process angle (SPA), which can be automatically measured. While angle measurement with ultrasound using spine transverse process-related landmarks (UCA) shows better agreed with XCA, its automatic measurement is challenging and not available yet. This research aimed to analyze and measure scoliotic angles through a novel semi-automatic UCA method. Methods 100 AIS subjects (age: 15.0 ± 1.9 years, gender: 19 M and 81 F, Cobb: 25.5 ± 9.6°) underwent both 3D ultrasound and X-ray scanning on the same day. Scoliotic angles with XCA and UCA methods were measured manually; and transverse process-related features were identified/drawn for the semi-automatic UCA method. The semi-automatic method measured the spinal curvature with pairs of thoracic transverse processes and lumbar lumps in respective regions. Results The new semi-automatic UCA method showed excellent correlations with manual XCA ( R 2  = 0.815: thoracic angles R 2  = 0.857, lumbar angles R 2  = 0.787); and excellent correlations with manual UCA ( R 2  = 0.866: thoracic angles R 2  = 0.921, lumbar angles R 2  = 0.780). The Bland–Altman plot also showed a good agreement against manual UCA/XCA. The MADs of semi-automatic UCA against XCA were less than 5°, which is clinically insignificant. Conclusion The semi-automatic UCA method had demonstrated the possibilities of estimating manual XCA and UCA. Further advancement in image processing to detect the vertebral landmarks in ultrasound images could help building a fully automated measurement method. Level of evidence Level III.