Comparison of Cobb Angles on Radiographs With Magnetic Resonance Imaging in Idiopathic Scoliosis (original) (raw)
Related papers
A Comparison of Cobb Angle: Standing Versus Supine Images of Late-onset Idiopathic Scoliosis
Polish Journal of Radiology, 2016
Background: Scoliosis is traditionally evaluated by measuring the Cobb angle in radiograph images taken while the patient is standing. However, low-dose computed tomography (CT) images, which are taken while the patient is in a supine position, provide new opportunities to evaluate scoliosis. Few studies have investigated how the patient's position, standing or supine, affects measurements. The purpose of this study was to compare the Cobb angle in images from patients while standing versus supine. Material/Methods: A total of 128 consecutive patients (97 females and 21 males; mean age 15.5 [11-26] years) with late-onset scoliosis requiring corrective surgery were enrolled. One observer evaluated the type of curve (Lenke classification) and measured the Cobb angle in whole-spine radiography (standing) and scout images from low-dose CT (supine) were taken on the same day. Results: For all primary curves, the mean Cobb angle was 59° (SD 12°) while standing and 48° (SD 12°) while in the supine position, with a mean difference of 11° (SD 5°). The correlation between primary standing and supine images had an r value of 0.899 (95% CI 0.860-0.928) and an intraclass correlation coefficient value of 0.969. The correlation between the difference in standing and supine images from primary and secondary curves had an r value of 0.340 (95% CI 0.177-0.484). Conclusions: We found a strong correlation between the Cobb angle in images obtained while the patient was standing versus supine for primary and secondary curves. This study is only applicable for patients with severe curves requiring surgical treatment. It enables additional studies based on low-dose CT.
Comparison of Cobb Angle Measurement in Scoliosis by Residents and Spine Experts
Coluna/Columna, 2016
Objective: The adolescent idiopathic scoliosis (AIS) is a spine deformity that occurs in both the coronal plane and the sagittal plane of patients between 10 and 17 years. The Cobb method is the most widely used to determine the angular value of scoliosis and it is defined as the "gold standard". The goal is to verify the reproducibility of the measured angles between orthopedic residents and spinal pathologies specialists, comparing the variability of the angles measured by professionals with greater and lesser experience. Method: A total of 10 radiographs of patients diagnosed with AIS were assessed. Radiographs were handed over to 7 orthopedists specialized in spine and 14 orthopedic residents. The measurement of the angles for each of the examiners was described using means and standard deviations and intraclass correlations were calculated, as well as the measure of repeatability, and Bland-Altman plots were designed with the results of the measurements of each group ...
Comparison of two- and three-dimensional measurement of the Cobb angle in scoliosis
International Orthopaedics, 2016
Purpose The Cobb angle as an objective measure is used to determine the progression of deformity, and is the basis in the planning of conservative and surgical treatment. However, studies have shown that the Cobb angle has two limitations: an inter-and intraobserver variability of the measurement is approximately 3-5 degrees, and high variability regarding the definition of the end vertebra. Scoliosis is a three-dimensional (3D) pathology, and 3D pathologies cannot be completely assessed by two-dimensional (2D) methods, like 2D radiography. The objective of this study was to determine the intraobserver and interobserver reliability of end vertebra definition and Cobb angle measurement using X-rays and 3D computer tomography (CT) reconstructions in scoliotic spines. Methods To assess interoberver variation the Cobb angle and the end vertebra were assessed by five observers in 55 patients using X-rays and 3D CT reconstructions. Definition of end vertebra and measurement of the Cobb angle was repeated two times with a three-week interval. Intraclass correlation coefficients (ICC) were used to determine the interobserver and intraobserver reliabilities. 95% prediction limits were provided for measurement errors. Results Intraclass correlation coefficient (ICC) showed excellent reliability for both methods. The measured Cobb angle was on average 9.2 degrees larger in the 3D CT group (72.8°, range 30-144) than on 2D radiography (63.6°, range 24-152). Conclusions In scoliosis treatment it is very essential to determine the curve magnitude, which is larger in a 3D measurement compared to 2D radiography.
The method for measurement of the three-dimensional scoliosis angle from standard radiographs
BMC Musculoskeletal Disorders, 2020
Background: Three-dimensional idiopathic scoliosis cannot be accurately assessed with the aid of a single plane parameterthe Cobb angle. We propose a novel method for evaluating the three-dimensional (3D) pattern of scoliosis based on two X-rays (PA and lateral). The proposed method consists of the measurements of the angles between the upper endplate of the upper-end vertebra and the lower endplate of the lower-end vertebra (3D scoliosis angle). Methods: The 3D-angles of thirty scoliosis curves were measured with either computed tomography (CT) or digitally reconstructed radiographs (DRRs): PA and lateral. CT was used as a reference. In the case of CT, the 3D angle was calculated based on the coordinates of three points situated on the upper endplate and those of three points situated on the lower endplate of the scoliosis curve. In the case of the DRR, the 3D angle was calculated using the four-angle method: the angles formed by the endplates of the curve with the transverse plane. The results were tested with the Student's t-test, and the agreement of measurements was tested with the intraclass correlation coefficient. Results: There was no significant difference between the 3D-angle measurements obtained with DRRs versus CT, p > 0.05. There was, however, a significant difference between the 3D-scoliosis angle and the Cobb angle measurements performed based on the X-rays. The reproducibility and reliability of 3D angle measurements were high. Conclusions: Based on two standard radiographs, PA and lateral, it is possible to calculate the 3D scoliosis angle. The proposed method facilitates 3D-scoliosis assessment without the use of sophisticated devices. Considering the 3D nature of AIS, the 3D parameters of the spine may help to apply a more effective treatment and estimate a more precise prognosis for patient with scoliosis.
Radiation-free quantitative assessment of scoliosis: a multi center prospective study
European Spine Journal, 2007
Accurate quantitative measurements of the spine are essential for deformity diagnosis and assessment of curve progression. There is much concern related to the multiple exposures to ionizing radiation associated with the Cobb method of radiographic measurement, currently the standard procedure for diagnosis and follow-up of the progression of scoliosis. In addition, the Cobb method relies on 2-D analysis of a 3-D deformity. The aim of this prospective study was to investigate the clinical value of Ortelius800TM that provides a radiation-free method for scoliosis assessment in three planes (coronal, sagittal, apical), with simultaneous automatic calculation of the Cobb angle in both coronal and sagittal views. Analysis of the clinical value of the device for assessing spinal deformities was performed on patients with adolescent idiopathic scoliosis, deformity angles ranging from 10° to 48°. Correlation between Cobb angles measured manually on standard erect posteroanterior radiographs and those calculated by Ortelius800TM showed an absolute difference between the measurements to be significantly less than ± 5° for coronal measurements and significantly less than ± 6° for sagittal measurements indicating good correlation between the two methods. The measurements from four independent sites and six independent examiners were not significantly different. We found the novel clinical tool to be reliable for following mild and moderate idiopathic curves in both coronal and sagittal planes, without exposing the patient to ionizing radiation. Considering the need for further validation of this new method, any change in treatment protocol should still be based on radiographic control.
Supine to standing Cobb angle change in idiopathic scoliosis: the effect of endplate pre-selection
Scoliosis, 2014
Supine imaging modalities provide valuable 3D information on scoliotic anatomy, but the altered spine geometry between the supine and standing positions affects the Cobb angle measurement. Previous studies report a mean 7°-10° Cobb angle increase from supine to standing, but none have reported the effect of endplate pre-selection or whether other parameters affect this Cobb angle difference. Cobb angles from existing coronal radiographs were compared to those on existing low-dose CT scans taken within three months of the reference radiograph for a group of females with adolescent idiopathic scoliosis. Reformatted coronal CT images were used to measure supine Cobb angles with and without endplate pre-selection (end-plates selected from the radiographs) by two observers on three separate occasions. Inter and intra-observer measurement variability were assessed. Multi-linear regression was used to investigate whether there was a relationship between supine to standing Cobb angle change...
Magnetic Resonance Imaging Evaluation of Patients With Idiopathic Scoliosis
Spine, 2011
Study Design. A prospective study of magnetic resonance imaging findings in outpatients with idiopathic scoliosis. Objective. The purpose of this study was to determine the prevalence of neural axis abnormalities in outpatients with scoliosis and to analyze the characteristics of patients who had such abnormalities. Summary of Background Data. In previous studies, neural axis abnormalities were found in 2.9% to 37% of patients with idiopathic scoliosis. The current guidelines for MRI screening in scoliosis are valuable, and the proposed indications for performing MRI in the literature include early onset, atypical curvature, double thoracic curve (King type-5), rapid progression, male gender, and abnormal neurologic findings. Methods. A total of 472 outpatients with a primary diagnosis of idiopathic scoliosis were examined for neural axis abnormalities by magnetic resonance imaging. Logistic regression was used to determine significant predictors of neural axis abnormalities on MRI. Results. The incidence of neural axis abnormalities on MRI was 3.8% (18 of 472 patients). Among the 18 patients, 6 had a Chiari I malformation alone, 10 had a Chiari I malformation combined with syringomyelia, and 2 had a syringomyelia without Chiari I malformation. Male gender, patients younger than 11 years old, and abnormal superficial abdominal reflexes were significantly associated with the detection of neural axis abnormalities on MRI. Conclusion. We recommend routine use of MRI in male patients, younger than 11 years old, and abnormal superficial abdominal reflexes. Even if a patient has no specific indications for MRI, we recommend its routine use in preoperative planning.
2020
Background This research analysed discrepancies between the angle of trunk rotation (ATR) and the Cobb angle, in order to study if the commonly used 7° cut-off threshold for ATR helps diagnose scoliosis. In early stadia of scoliosis in children, ATR and the Cobb angle often disagree, increasing the risk of a false diagnosis: while the former does not suggest scoliosis, the latter does. Methods The study analysed ATR clinical parameters and the Cobb angle in the X-ray pictures of 117 (23 boys and 94 girls, aged 6–17 years) children who had not yet started treatment and whose X-ray pictures showed the Cobb angle of at least 10°, indicating idiopathic scoliosis. The degrees of lumbar lordosis and thoracic kyphosis were measured using the Saunders inclinometer, and back asymmetry was measured with Adam’s forward bend test using the Bunnell scoliometer. In the X-ray pictures, the curvature angle was plotted according to the Cobb method. The patients were stratified based on their age, an...