• Tomaž Vrtovec University of Ljubljana, Faculty of Electrical Engineering, Laboratory of Imaging Technologies
  • Franjo Pernuš University of Ljubljana, Faculty of Electrical Engineering, Laboratory of Imaging Technologies
  • Boštjan Likar University of Ljubljana, Faculty of Electrical Engineering, Laboratory of Imaging Technologies



computed tomography, computerized measurements, coronal vertebral inclination, manual measurements, measurement variability


Objective measurement of coronal vertebral inclination (CVI) is of significant importance for evaluating spinal deformities in the coronal plane. The purpose of this study is to systematically analyze and compare manual and computerized measurements of CVI in cross-sectional and volumetric computed tomography (CT) images. Three observers independently measured CVI in 14 CT images of normal and 14 CT images of scoliotic vertebrae by using six manual and two computerized measurements. Manual measurements were obtained in coronal cross-sections by manually identifying the vertebral body corners, which served to measure CVI according to the superior and inferior tangents, left and right tangents, and mid-endplate and mid-wall lines. Computerized measurements were obtained in two dimensions (2D) and in three dimensions (3D) by manually initializing an automated method in vertebral centroids and then searching for the planes of maximal symmetry of vertebral anatomical structures. The mid-endplate lines were the most reproducible and reliable manual measurements (intra- and inter-observer variability of 0.7° and 1.2° standard deviation, SD, respectively). The computerized measurements in 3D were more reproducible and reliable (intra- and inter-observer variability of 0.5° and 0.7° SD, respectively), but were most consistent with the mid-wall lines (2.0° SD and 1.4° mean absolute difference). The manual CVI measurements based on mid-endplate lines and the computerized CVI measurements in 3D resulted in the lowest intra-observer and inter-observer variability, however, computerized CVI measurements reduce observer interaction.


Adam CJ, Izatt MT, Harvey JR, Askin GN (2005). Variability in Cobb angle measurements using reformatted computerized tomography scans. Spine 30:1664-9.

Allen S, Parent E, Khorasani M, Hill DL, Lou E, Raso JV (2008). Validity and reliability of active shape models for the estimation of Cobb angle in patients with adolescent idiopathic scoliosis. J Digit Imaging 21:208-18.

Capasso G, Maffulli N, Testa V (1992). The validity and reliability of measurements in spinal deformities: a critical appraisal. Acta Orthop Belg 58:126-35.

Carman DL, Browne RH, Birch JG (1990). Measurement of scoliosis and kyphosis radiographs: intraobserver and interobserver variation. J Bone Joint Surg Am 72:328-33.

Chen Y-L, Chen W-J, Chiou W-K (2007). An alternative method for measuring scoliosis curvature. Orthopedics 30:828-31.

Cheung J, Wever DJ, Veldhuizen AG, Klein JP, Verdonck B, Nijlunsing R, Cool JC, Van Horn JR (2002). The reliability of quantitative analysis on digital images of the scoliotic spine. Eur Spine J 11:535-42.

Chockalingam N, Dangerfield PH, Giakas G, Cochrane T, Dorgan JC (2002). Computer-assisted Cobb measurement of scoliosis. Eur Spine J 11:353-7.

Cobb JR (1948). Outline for the study of scoliosis. Am Acad Orthop Surg Instr Course Lect 5:261-75.

De Carvalho A, Vialle R, Thomsen L, Amzallag J, Cluzel G, Pointe H, Mary P (2007). Reliability analysis for manual measurement of coronal plane deformity in adolescent scoliosis. Are 30 x 90 cm plain films better than digitized small films? Eur Spine J 16:1615-20.

Diab KM, Sevastik JA, Hedlund R, Suliman IA (1995). Accuracy and applicability of measurement of the scoliotic angle at the frontal plane by Cobb's method, by Ferguson's method and by a new method. Eur Spine J 4:291-5.

Dutton KE, Jones TJ, Slinger BS, Scull ER, O'Connor J (1989). Reliability of the Cobb angle index derived by traditional and computer assisted methods. Australas Phys Eng Sci Med 12:16-23.

Facanha-Filho FA, Winter RB, Lonstein JE, Koop S, Novacheck T, L'Heureux EA, Noren CA (2001). Measurement accuracy in congenital scoliosis. J Bone Joint Surg Am 83:42-5.

Ferguson AB (1930). The study and treatment of scoliosis. South Med J 23:116-20.

Goldberg MS, Poitras B, Mayo NE, Labelle H, Bourassa R, Cloutier R (1988). Observer variation in assessing spinal curvature and skeletal development in adolescent idiopathic scoliosis. Spine 13:1371-7.

Gstoettner M, Sekyra K, Walochnik N, Winter P, Wachter R, Bach CM (2007). Inter- and intraobserver reliability assessment of the Cobb angle: manual versus digital measurement tools. Eur Spine J 16:1587-92.

Jeffries BF, Tarlton M, {De Smet} AA, Dwyer SJ, Brower AC (1980). Computerized measurement and analysis of scoliosis: a more accurate representation of the shape of the curve. Radiology 134:381-5.

Loder RT, Urquhart A, Steen H, Graziano G, Hensinger RN, Schlesinger A, Schork MA, Shyr Y (1995). Variability in Cobb angle measurements in children with congenital scoliosis. J Bone Joint Surg Br 77:768-70.

Loder RT, Spiegel D, Gutknecht S, Kleist K, Ly T, Mehbod A (2004). The assessment of intraobserver and interobserver error in the measurement of noncongenital scoliosis in children less or equal 10 years of age. Spine 29:2548-53.

Mok JM, Berven SH, Diab M, Hackbarth M, Hu SS, Deviren V (2008). Comparison of observer variation in conventional and three digital radiographic methods used in the evaluation of patients with adolescent idiopathic scoliosis. Spine 33:681-6.

Oda M, Rauh S, Gregory PB, Silverman FN, Bleck EE (1982). The significance of roentgenographic measurement in scoliosis. J Pediatr Orthop 2:378-82.

Pruijs JE, Hageman MA, Keessen W, van der Meer R, van Wieringen JC (1994). Variation in Cobb angle measurements in scoliosis. Skeletal Radiol 23:517-20.

Shea KG, Stevens PM, Nelson M, Smith JT, Masters KS, Yandow S (1998). A comparison of manual versus computer-assisted radiographic measurement: intraobserver measurement variability for Cobb angles. Spine 23:551-5.

Stokes IAF, Aronsson DD (2006). Computer-assisted algorithms improve reliability of King classification and Cobb angle measurement of scoliosis. Spine 31:665-70.

Tanure MC, Pinheiro AP, Oliveira AS (2010). Reliability assessment of Cobb angle measurements using manual and digital methods. Spine J 10:769-74.

Vrtovec T, Pernuš F, Likar B (2008). A symmetry-based method for the determination of vertebral rotation in 3D. Lect Notes Comput Sc 5241:942-50.

Vrtovec T, Likar B, Pernuš F (2013). Manual and computerized measurement of coronal vertebral inclination in MRI images: a pilot study. Clin Radiol 68:807-14.

Wills BPD, Auerbach JD, Zhu X, Caird MS, Horn BD, Flynn JM, Drummond DS, Dormans JP, Ecker ML (2007). Comparison of Cobb angle measurement of scoliosis radiographs with preselected end vertebrae: traditional versus digital acquisition. Spine 32:98-105.

Ylikoski M, Tallroth K (1990). Measurement variations in scoliotic angle, vertebral rotation, vertebral body height, and intervertebral disc space height. J Spinal Disord Tech 3:387-91.

Zhang J, Lou E, Shi X, Wang Y, Hill DL, Raso JV, Le LH, Lv L (2010). A computer-aided Cobb angle measurement method and its reliability. J Spinal Disord Tech 23:383-7.




How to Cite




Original Research Paper