Computer-aided Measurement System Using Image Processing for Measuring Cobb Angle in Scoliosis

Background: One of the spine deformities is scoliosis, and Cobb angle is generally used to assess it. Objectives: In this study, a computer-aided measurement system (CAMS) was presented as a new repeatable and reproducible approach to assess the Cobb angle in idiopathic scoliosis patients. Methods: Python libraries, including OpenCV and Numpy were used for image processing and design of the software. To assess the repeatability and reproducibility of the CAMS, a series of 98 anterior-posterior radiographs from patients with idiopathic scoliosis were used. Assessments were done by five independent observers. Each radiograph was assessed by each observer three times with a minimum break of two weeks among assessment. The single measure intraclass correlation coefficient (ICC), the mean absolute difference (MAD), and the standard error measurement (SEM) values were used for intra- and inter-observer reliability. Results: The inter-observer analysis indicated that the ICCs ranged from 0.94 - 0.99, and the MAD between manual and CAMS were less than 3°. For intra-observer measurements, the combined SEM between all observers for the manual and CAMS was 1.79° and 1.27°, respectively. An ICC value of 0.97 with 95% confidence interval (CI) was excellent in CAMS for inter-observer reliability. The MAD of CAMS was 2.18 ± 2.01 degrees. Conclusions: The CAMS is an effective and reliable approach for assessing scoliotic curvature in the standing radiographs of thoraco-lumbar. Moreover, CAMS can accelerate clinical visits, and its calculation results are reliable.

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A Novel Computer-Aided Method to Evaluate Scoliosis Curvature using Polynomial Math Function

Journal of Biomedical Physics and Engineering ◽

10.31661/jbpe.v0i0.1194 ◽

2019 ◽

Author(s):

D F Guamán-Lozada ◽

J Cabrera-Escobar ◽

M D Guamán-Lozada ◽

V Romero-Rodríguez ◽

A P Castro-Martin ◽

...

Keyword(s):

Cobb Angle ◽

Pearson Correlation ◽

Intraclass Correlation ◽

Correlation Method ◽

Plain Film ◽

Spinal Curvature ◽

Plain Films ◽

Computer Aided ◽

Spine Curvature ◽

Cobb Method

Introduction: Scoliosis is a health problem that causes a side-to-side curvature in the spine. The curvature may have an “S” or “C” shape. To evaluate scoliosis, the Cobb angle has been commonly used. However, digital image processing allows the Cobb angle to be obtained easily and quickly, several researchers have determined that Cobb angle contains high variations (errors) in the measurements. Therefore, a more reproducible computer aided-method to evaluate scoliosis is presented.Material and Methods: Several polynomial curves were fitted to the spine curvature (4th to 8th order) of thirty plain films of scoliosis patients to obtain the Curvature-Length of the spine. Each plain film was evaluated by 3 physician observers. Curvature was measured twice using the Cobb method and the proposed Curvature-Length Technique (CLT). Data were analyzed by a paired-sample Student t-test and Pearson correlation method using SPSS Statistics 25.Results: The curve of 7th order polynomial had the best fit on the spine curvature and was also used for our proposed method (CLT) obtaining a significant positive correlation when compared to Cobb measurements (r=0.863, P<0.001). The Intraclass Correlation (ICC) was between 0.863 and 0.948 for Cobb method and0.974 to 0.984 for CLT method. In addition, mean measurement of the inter-observer COV (Coefficient of Variation) for Cobb method was of 0.185, that was significantly greater than the obtained with CLT method of 0.155, this means that CLT method is 16.2% more repeatable than Cobb Method.Conclusion: Based on results, it was concluded that CLT method is more reproducible than the Cobb method for measuring spinal curvature.

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Assessment of the plane of maximum curvature for patients with adolescent idiopathic scoliosis via computed tomography

Prosthetics and Orthotics International ◽

10.1177/0309364620941297 ◽

2020 ◽

Vol 44 (5) ◽

pp. 298-304

Author(s):

Hui-Dong Wu ◽

Winnie Chiu-Wing Chu ◽

Cheng-Qi He ◽

Man-Sang Wong

Keyword(s):

Computed Tomography ◽

Adolescent Idiopathic Scoliosis ◽

Idiopathic Scoliosis ◽

Cobb Angle ◽

Correlation Coefficient ◽

Intraclass Correlation ◽

Intrarater Reliability ◽

Maximum Curvature ◽

Curvature Measurements ◽

The Mean

Background: In the assessment of three-dimensional features of adolescent idiopathic scoliosis, the plane of maximum curvature was compared with the coronal Cobb angle. Objectives: To investigate the intrarater reliability, variability, and difference of the prone plane of maximum curvature measurements taken from computed tomography using the constrained and unconstrained Cobb methods; to assess the difference and correlation between the prone plane of maximum curvature measurements obtained using the constrained and unconstrained Cobb methods; and to examine differences and correlation between the prone plane of maximum curvature Cobb angle and coronal Cobb angle measurements. Study design: Retrospective study. Methods: Records of 29 subjects with adolescent idiopathic scoliosis aged 15.8 ± 3.5 years were reviewed (25 thoracic and 24 thoracolumbar/lumbar curves). An experienced rater measured the plane of maximum curvature using the constrained and unconstrained Cobb methods, and the coronal Cobb angles using the conventional Cobb method on computed tomography images 3 times each with 1-week interval. The intraclass correlation coefficient (2,1), Pearson correlation coefficient ( r), one-way repeated measures analysis of variance, and paired t test were applied for various analyses. Results: The intraclass correlation coefficients for all intrarater reliability assessments were greater than 0.87. The plane of maximum curvature measurements of the two Cobb methods were excellently correlated ( r ⩾ 0.97) with no significant difference ( P > 0.05). The mean plane of maximum curvature Cobb angle was moderately correlated with ( r > 0.72) but significantly greater ( P < 0.001) than the mean coronal Cobb angle. Conclusion: The plane of maximum curvature measurements obtained from computed tomography were found to be reliable while the plane of maximum curvature measurements of the two Cobb methods were comparable. The mean plane of maximum curvature Cobb angle was moderately correlated with but significantly greater than the mean coronal Cobb angle. Clinical relevance The plane of maximum curvature measurements taken from computed tomography was found to be reliable, hence it could be used as a supplement to the coronal Cobb angle in the assessment and management of adolescent idiopathic scoliosis. With technological advancement, the radiation dose of computed tomography can be further reduced to a safer level for a broader range of cases.

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Computer-Aided Cobb Measurement Based on Automatic Detection of Vertebral Slopes Using Deep Neural Network

International Journal of Biomedical Imaging ◽

10.1155/2017/9083916 ◽

2017 ◽

Vol 2017 ◽

pp. 1-6 ◽

Cited By ~ 11

Author(s):

Junhua Zhang ◽

Hongjian Li ◽

Liang Lv ◽

Yufeng Zhang

Keyword(s):

Neural Network ◽

Cobb Angle ◽

Deep Neural Network ◽

Intraclass Correlation ◽

Correlation Coefficients ◽

Angle Measurement ◽

Training Data ◽

Manual Measurement ◽

Computer Aided

Objective. To develop a computer-aided method that reduces the variability of Cobb angle measurement for scoliosis assessment. Methods. A deep neural network (DNN) was trained with vertebral patches extracted from spinal model radiographs. The Cobb angle of the spinal curve was calculated automatically from the vertebral slopes predicted by the DNN. Sixty-five in vivo radiographs and 40 model radiographs were analyzed. An experienced surgeon performed manual measurements on the aforementioned radiographs. Two examiners used both the proposed and the manual measurement methods to analyze the aforementioned radiographs. Results. For model radiographs, the intraclass correlation coefficients were greater than 0.98, and the mean absolute differences were less than 3°. This indicates that the proposed system showed high repeatability for measurements of model radiographs. For the in vivo radiographs, the reliabilities were lower than those from the model radiographs, and the differences between the computer-aided measurement and the manual measurement by the surgeon were higher than 5°. Conclusion. The variability of Cobb angle measurements can be reduced if the DNN system is trained with enough vertebral patches. Training data of in vivo radiographs must be included to improve the performance of DNN. Significance. Vertebral slopes can be predicted by DNN. The computer-aided system can be used to perform automatic measurements of Cobb angle, which is used to make reliable and objective assessments of scoliosis.

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APPLICABILITY OF THE COBB ANGLE MEASUREMENT IN IDIOPATHIC SCOLIOSIS USING SCANNED IMAGING

Coluna/Columna ◽

10.1590/s1808-185120171601153058 ◽

2017 ◽

Vol 16 (1) ◽

pp. 22-24

Author(s):

ERASMO DE ABREU ZARDO ◽

MARCUS SOFIA ZIEGLER ◽

AFRANE SERDEIRA ◽

CARLOS MARCELO DONAZAR SEVERO ◽

RODRIGO VALENTE FRAST ◽

...

Keyword(s):

Idiopathic Scoliosis ◽

Cobb Angle ◽

Intraclass Correlation ◽

Angle Measurement ◽

Average Variation ◽

Cobb Angle Measurement ◽

Spine Surgeon ◽

Cobb Method ◽

Main Curve ◽

Excellent Reproducibility

ABSTRACT Objectives: To compare the measurement of the Cobb angle on printed radiographs and on scanned radiographs viewed through the software "PixViewer". Methods: Preoperative radiographs of 23 patients were evaluated on printed films and through the software "PixViewer". The same evaluator, a spine surgeon, chose the proximal and distal limiting vertebrae of the main curve on printed radiographs, without identification of patients, and measured the Cobb angle based on these parameters. The same parameters and measurements were applied to scanned radiographs. The measurements were compared, as well as the choice of limiting vertebrae. Results: The average variation of the Cobb angle between methods was 1.48 ± 1.73°. The intraclass correlation coefficient (ICC) was 0.99, demonstrating excellent reproducibility. Conclusion: The Cobb method can be used to evaluate scoliosis through the "PixViewer" tool with the same reliability as the classic method on printed radiographs.

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Intra- and inter-observer reliability of Cobb angle measurements in patients with adolescent idiopathic scoliosis

Spine Deformity ◽

10.1007/s43390-021-00398-0 ◽

2021 ◽

Author(s):

F. G. Prestigiacomo ◽

M. H. H. M. Hulsbosch ◽

V. E. J. Bruls ◽

J. J. Nieuwenhuis

Keyword(s):

Adolescent Idiopathic Scoliosis ◽

Idiopathic Scoliosis ◽

Cobb Angle ◽

Observer Reliability ◽

Angle Measurements

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Upper instrumented vertebra to the right of the lowest instrumented vertebra as a predictor of an increase in the main thoracic curve after selective posterior fusion for the thoracolumbar/lumbar curve in Lenke type 5C adolescent idiopathic scoliosis: multicenter study on the relationship between fusion area and surgical outcome

Journal of Neurosurgery Spine ◽

10.3171/2019.5.spine181469 ◽

2019 ◽

Vol 31 (6) ◽

pp. 857-864 ◽

Cited By ~ 1

Author(s):

Hiroki Oba ◽

Jun Takahashi ◽

Sho Kobayashi ◽

Tetsuro Ohba ◽

Shota Ikegami ◽

...

Keyword(s):

Adolescent Idiopathic Scoliosis ◽

Idiopathic Scoliosis ◽

Cobb Angle ◽

Posterior Fusion ◽

Main Thoracic ◽

Lowest Instrumented Vertebra ◽

Line Tilt ◽

The Right ◽

Upper Instrumented Vertebra

OBJECTIVEUnfused main thoracic (MT) curvatures occasionally increase after selective thoracolumbar/lumbar (TL/L) fusion. This study sought to identify the predictors of an unacceptable increase in MT curve (UIMT) after selective posterior fusion (SPF) of the TL/L curve in patients with Lenke type 5C adolescent idiopathic scoliosis (AIS).METHODSForty-eight consecutive patients (44 females and 4 males, mean age 15.7 ± 2.5 years, range 13–24 years) with Lenke type 5C AIS who underwent SPF of the TL/L curve were analyzed. The novel “Shinshu line” (S-line) was defined as a line connecting the centers of the concave-side pedicles of the upper instrumented vertebra (UIV) and lowest instrumented vertebra (LIV) on preoperative radiographs. The authors established an S-line tilt to the right as S-line positive (S-line+, i.e., the UIV being to the right of the LIV) and compared S-line+ and S-line− groups for thoracic apical vertebral translation (T-AVT) and MT Cobb angle preoperatively, early postoperatively, and at final follow-up. The predictors for T-AVT > 20 mm at final follow-up were evaluated as well. T-AVT > 20 mm was defined as a UIMT.RESULTSAmong the 48 consecutively treated patients, 26 were S-line+ and 22 were S-line−. At preoperative, early postoperative, and final follow-up a minimum of 2 years later, the mean T-AVT was 12.8 mm (range −9.3 to 32.8 mm), 19.6 mm (range −13.0 to 41.0 mm), and 22.8 mm (range −1.9 to 68.7 mm) in the S-line+ group, and 10.8 mm (range −5.1 to 27.3 mm), 16.2 mm (range −11.7 to 42.1 mm), and 11.0 mm (range −6.3 to 26.9 mm) in the S-line− group, respectively. T-AVT in S-line+ patients was significantly larger than that in S-line− patients at the final follow-up. Multivariate analysis revealed S-line+ (odds ratio [OR] 23.8, p = 0.003) and preoperative MT Cobb angle (OR 7.9, p = 0.001) to be predictors of a UIMT.CONCLUSIONSS-line+ was defined as the UIV being to the right of the LIV. T-AVT in the S-line+ group was significantly larger than in the S-line− group at the final follow-up. S-line+ status and larger preoperative MT Cobb angle were independent predictors of a UIMT after SPF for the TL/L curve in patients with Lenke type 5C AIS. Surgeons should consider changing the UIV and/or LIV in patients exhibiting S-line+ during preoperative planning to avoid a possible increase in MT curve and revision surgery.

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Clinical predictive model of lumbar curve Cobb angle below selective fusion for thoracic adolescent idiopathic scoliosis: a longitudinal multicenter descriptive study

European Journal of Orthopaedic Surgery & Traumatology ◽

10.1007/s00590-021-03054-5 ◽

2021 ◽

Author(s):

Federico Solla ◽

Walid Lakhal ◽

Christian Morin ◽

Jerome Sales de Gauzy ◽

Gaby Kreichati ◽

...

Keyword(s):

Adolescent Idiopathic Scoliosis ◽

Idiopathic Scoliosis ◽

Cobb Angle ◽

Predictive Model ◽

Descriptive Study ◽

Lumbar Curve ◽

Selective Fusion ◽

Clinical Predictive Model

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Sagittal profile modifications in hybrid versus all screw technique in adolescent idiopathic scoliosis

Scientific Reports ◽

10.1038/s41598-020-79523-4 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Laura Scaramuzzo ◽

Antonino Zagra ◽

Giuseppe Barone ◽

Stefano Muzzi ◽

Leone Minoia ◽

...

Keyword(s):

Adolescent Idiopathic Scoliosis ◽

Idiopathic Scoliosis ◽

Cobb Angle ◽

Thoracic Kyphosis ◽

Sagittal Alignment ◽

Vertical Axis ◽

Sagittal Profile ◽

Sacral Slope ◽

Sagittal Vertical Axis ◽

Lenke Classification

AbstractAim of the study was to evaluate sagittal parameters modifications, with particular interest in thoracic kyphosis, in patients affected by adolescent idiopathic scoliosis (AIS) comparing hybrid and all-screws technique. From June 2010 to September 2018, 145 patients were enrolled. Evaluation included: Lenke classification, Risser scale, coronal Cobb angle, thoracic kyphosis (TK), lumbar lordosis (LL), sagittal vertical axis (SVA), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS). Patients were divided in two groups (1 all-screws and 2 hybrid); a further division, in both groups, was done considering preoperative TK values. Descriptive and inferential statistical analysis was conducted. 99 patients were in group 1, 46 in group 2 (mean follow-up 3.7 years). Patients with a normo-kyphotic profile developed a little variation in TK (Δ pre–post = 2.4° versus − 2.0° respectively). Hyper-kyphotic subgroups had a tendency of restoring a good sagittal alignment. Hypo-kyphotic subgroups, patients treated with all-screw implants developed a higher increase in TK mean Cobb angle (Δ pre–post = 10°) than the hybrid subgroup (Δ pre–post = 5.4°) (p = 0.01). All-screws group showed better results in restoring sagittal alignment in all subgroups compared to hybrid groups, especially in hypo-TK subgroup, with the important advantage to give better correction on coronal plane.

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Comparison of Changes in SRS-22 Values with Improvement in Cobb Angles after Posterior Fusion Surgery in Adolescent Idiopathic Scoliosis

Zeitschrift für Orthopädie und Unfallchirurgie ◽

10.1055/a-1401-0477 ◽

2021 ◽

Author(s):

Kadir Gem ◽

Sertan Hancioglu ◽

Abdulkadir Bilgiç ◽

Serkan Erkan

Keyword(s):

Adolescent Idiopathic Scoliosis ◽

Idiopathic Scoliosis ◽

Cobb Angle ◽

Posterior Instrumentation ◽

Research Society ◽

Posterior Fusion ◽

Improvement Rate ◽

Scoliosis Research Society ◽

Correction Rate ◽

Group B

Abstract Introduction The purpose of this study was to evaluate the relationship between the correction rate in Cobb angle and the improvement in quality of life profile in terms of Scoliosis Research Society (SRS)-22 values. Patients and Methods Between January 2007 and December 2013, posterior instrumentation and fusion was performed to 30 patients with adolescent idiopathic scoliosis (AIS). Patients were grouped according to their improvement rate in Cobb angles after surgery. Patients with an improvement rate of > 80% were grouped as Group A; those with an improvement rate of > 60% and ≤ 80% as Group B and those with an improvement rate of ≤ 60% were grouped as Group C. The SRS-22 questionnaire of these three groups was calculated and their relationship with the improvement in Cobb angle was evaluated. Results No statistical difference was found among the three groups in terms of pain, appearance, function, spirit, satisfaction, and SRS-22 values (all p > 0.05). Conclusion The results of this study demonstrate that the degree of correction rate does not correlate with the degree of improvement in the SRS-22 questionnaire in patients with AIS that underwent posterior fusion and instrumentation.

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