Cross-sectional study. To compare the relative contribution of the vertebral bodies and intervertebral discs with the 3-dimensional spinal deformity in adolescent idiopathic scoliosis. There is an ongoing discussion about the causal role of skeletal growth processes in the etiopathogenesis of adolescent idiopathic scoliosis. Contradictory findings have been reported on the individual contribution of the vertebral bodies as compared with the discs to the coronal deformity. As far as we know, the true 3-dimensional deformity of the discs and vertebral bodies have not yet been described. High-resolution computed tomographic scans of 77 patients with severe adolescent idiopathic scoliosis were included. Torsion and anterior-posterior and right-left asymmetry of each individual vertebral body and intervertebral disc were studied from T2 to L5, using semiautomatic analysis software. True transverse sections were reconstructed along the anterior-posterior and right-left axis of all endplates. These "endplate-vectors" were calculated semiautomatically, taking rotation and tilt into account. Torsion was defined as the difference in axial rotation between 2 subsequent endplates. Asymmetry was defined as the relative anterior-posterior or right-left height difference of the discs and the vertebrae. There were at least 3 times more torsion, anterior overgrowth, and coronal wedging in the discs than in the vertebrae in the thoracic as well as in the (thoraco) lumbar curves (P<0.001). These values correlated significantly with the Cobb angle (r≥0.37; P<0.001). Anterior overgrowth and coronal asymmetry were greater in the apical regions whereas torsion was most pronounced in the transitional segments between the curves. The discs contribute more to 3-D deformity than the bony structures, and there is significant regional variability. This suggests an adaptive rather than an active phenomenon. 2.

Knee Image Digital Analysis (KIDA) is standardized radiographic analysis software for measuring osteoarthritis (OA) characteristics. It was validated in mild OA, but used for severe OA as well. The current goal was to evaluate the performance of KIDA in severe OA. Of 103 patients, standardized radiographs were performed before and one and 2 years after treatment for severe OA. All radiographs were evaluated on subchondral bone density, joint space width (JSW), osteophytes, eminence height, and joint angle, twice within years by the same observer. Part of the radiographs were randomly selected for reevaluation twice within 1 month and evaluation by another observer. The intraclass correlation coefficient (ICC), smallest detectable difference (SDD) and coefficient of variation (CV) were calculated; the SDD and CV were compared to those in mild OA. The relation of severity with KIDA parameters and with observer differences was calculated with linear regression. Intra-observer ICCs were higher in the 98 severe radiographs reanalyzed within 1 month (all >0.8) than the 293 reanalyzed within years (all >0.5; most >0.8) and than inter-observer ICCs (all >0.7). SDDs and CVs were smaller when reanalyzed within a month and comparable to those in mild OA. Some parameters showed bias between readings. Severity showed significant relation with osteophytes and JSW parameters, and with the observer variation in these parameters (all P < 0.04). KIDA is a well-performing tool also for severe OA. In order to decrease variability and SDDs, images should be analyzed in a limited time frame and randomized order.

Quantification of the severity of chest wall deformation in children with spinal deformities is essential for understanding the effects on trunk appearance and cardiopulmonary function. Magnetic resonance imaging (MRI) is particularly valuable for this purpose, as it does not employ ionizing radiation and can provide three-dimensional (3D) imaging of thoracic anatomy. Acquiring sufficient quality images of the chest wall, lungs and airways at key stages of the respiratory cycle, such as end-inspiratory or expiratory phase, is crucial for accurately assessing chest wall deformation and pulmonary function and mechanics. Regarding image quality, low proton density and short relaxation times of the lung tissues result in poor quality images, and long acquisition times result in blurring caused by respiratory and cardiac motion. This overview summarizes strategies developed to address the inherent challenges of visualization of lung tissue and respiratory motion in MRI acquisition of the chest of pediatric patients with spinal deformities. An overview of the main methods for motion-resolved image acquisition and measurement of chest wall motion and thoracic volumes is presented and discussed. It is concluded that despite the development of multiple techniques and diverse strategies for obtaining high-quality, motion-resolved chest MRI, further validation of these methods is required before their implementation in clinics for routine evaluation of chest deformation in pediatric spinal deformity patients.