Correction to: Inter- and intra-observer reliability of contrast-enhanced magnetic resonance imaging parameters in children with suspected juvenile idiopathic arthritis of the hip.

The article "Inter- and intra-observer reliability of contrast-enhanced magnetic resonance imaging parameters in children with suspected juvenile idiopathic arthritis of the hip".

Inter- and intra-observer reliability of contrast-enhanced magnetic resonance imaging parameters in children with suspected juvenile idiopathic arthritis of the hip.

BACKGROUND: Previous work at our institution demonstrated discrepancies between radiologists in interpretation of contrast-enhanced magnetic resonance imaging (MRI) in suspected hip arthritis. OBJECTIVE: To assess inter- and intra-observer reliability of selected MRI parameters (effusion, marrow oedema and synovial thickness and enhancement) used in the diagnosis of juvenile idiopathic arthritis. MATERIALS AND METHODS: A retrospective cohort study was conducted of patients with confirmed or suspected juvenile idiopathic arthritis who underwent hip contrast-enhanced MRI between January 2011 and September 2014. Three pediatric musculoskeletal radiologists independently assessed all scans for effusion, marrow oedema, measurement of synovial thickness, synovial enhancement and subjective assessment of synovium. Categorical variables were analysed using the Cohen κ, and measurement using Bland-Altman plots. RESULTS: Eighty patients were included. Interobserver reliability was moderate for effusion (κ=0.5-0.7), marrow oedema (κ=0.6), subjective synovial assessment (κ=0.4-0.5) and synovial enhancement (κ=0.1-0.5). Intra-observer reliability was highest for marrow oedema (κ=0.6-0.8) and lowest for effusion (κ=0.4-0.7). Intra-observer reliability for synovial enhancement (κ= -0.7-0.8) and subjective synovial assessment (κ=0.4-1.0) ranged from poor to excellent. For synovial thickness, intra- and interobserver Bland-Altman plots were well clustered around the mean suggesting good agreement. CONCLUSION: There were large differences across variables and only moderate agreement between observers. The most reliable parameters were presence of joint effusion and bone marrow oedema and subjective assessment of synovium.

Hip and groin pain in the child athlete.

An increasing number of children are taking up sporting activities and at more competitive levels. For this reason (pediatric) radiologists should expect to receive greater numbers of requests from their orthopedic colleagues to image the athletic child who presents with hip or groin pain: "athletic pubalgia."Lower limb sports-related pathology is particularly common in sports such as ballet, football, hockey, rugby, and running. Injuries to the hip and groin may account for up to a quarter of injuries seen in athletic children and may be acute or chronic, osseous, cartilaginous, ligamentous, or muscular. The radiologist should also bear in mind the possibility of non-sports-related pathology such as inflammation or tumor and of complications related to previous trauma such as avascular necrosis or femoroacetabular impingement complicating previous slipped capital femoral epiphysis. Radiologists should avoid use of the term sports hernia and provide a more specific description of the true abnormality.The major imaging modalities are radiographs and MRI. In this article we provide an overview of the common sports-related pathologies of the hip and groin that may be encountered in the athletic child.

Diagnostic performance of morphometric vertebral fracture analysis (MXA) in children using a 33-point software program.

BACKGROUND: There is significant inter and intraobserver variability in diagnosing vertebral fractures in children. PURPOSE: We aimed to evaluate the diagnostic accuracy of morphometric vertebral fracture analysis (MXA) using a 33-point software program designed for adults, on dual-energy x-ray absorptiometry (DXA) images of children. MATERIALS AND METHODS: Lateral spine DXA images of 420 children aged between 5 and 18 years were retrospectively reviewed. Vertebral fracture assessment (VFA) by an expert pediatric radiologist using Genant's semiquantitative scoring system served as the gold standard. All 420 DXA scans were analyzed by a trained radiographer, using semi-automated software (33-point morphometry). VFA of a random sample of 100 DXA was performed by an experienced pediatric clinical scientist. MXA of a random sample of 30 DXA images were analyzed by three pediatric radiologists and the pediatric clinical scientist. Diagnostic accuracy and inter and intraobserver agreement (kappa statistics) were calculated. RESULTS: Overall sensitivity, specificity, false positive (FP) and false negative (FN) rates for the radiographer using the MXA software were 80%, 90%, 10%, and 20% respectively and for mild fractures alone were 46%, 92%, 8%, and 54% respectively. Overall sensitivity, specificity, FP, and FN rates for the four additional observers using MXA were 89%, 79%, 21%, and 11% respectively and for mild fractures alone were 36%, 86%, 14%, and 64% respectively. Agreement between two expert observers was fair to good for VFA and MXA [kappa = 0·29 to 0·76 (95% CI: 0·17-0·88) and 0·29 to 0·69 (95% CI: 0·17-0·83)] respectively. CONCLUSION: MXA using a 33-point technique developed for adults is not a reliable method for the identification of mild vertebral fractures in children. A pediatric standard is required which not only incorporates specific vertebral body height ratios but also the age-related physiological changes in vertebral shape that occur throughout childhood.