To assess the discriminatory ability of vertebra-specific volumetric bone mineral density (vBMD), finite element analysis-derived fracture load (FEA-derived FL), and texture analysis (TA) features for incidental vertebral fractures, and to compare performance between thoracic and lumbar levels. We retrospectively reviewed baseline and follow-up thoracolumbar CT scans from 420 patients and identified 11 patients with incidental vertebral fractures contributing to 20 fractured vertebrae (7 females; mean age 65.5years). For each fractured vertebra, three level-matched control vertebrae from patients without fractures were selected, yielding 58 controls across 29 control patients (total 78 vertebrae). Parameters evaluated include vBMD, FEA-derived FL, and TA features (24 total). Discriminatory ability was assessed using area under the curve (AUC) values. vBMD, FEA-derived FL, and 4 of 24 TA features showed group-wise differences between fractured and control vertebrae groups. AUCs were 0.76 [95% CI 0.55-0.90] (vBMD) and 0.73 [95% CI 0.52-0.90] (FEA-derived FL); selected texture features ranged 0.70-0.72. Region-stratified AUC point estimates were higher in the lumbar than in the thoracic vertebrae, but the 95% CIs were wide/overlapping; comparisons are descriptive. vBMD had the numerically largest AUC point estimate for discriminating fractured from control vertebrae; FEA-derived FL was similar, and selected texture features showed modest discrimination with comparable point estimates across lumbar and thoracic levels, generating the hypothesis of less region dependence. Regional comparisons are descriptive. Findings are exploratory and intended to prioritize candidate measures for validation and future multivariable modeling before any clinical application.

To investigate femoral head epiphysis perfusion via dynamic contrast-enhanced MRI (DCE-MRI) in children with developmental dysplasia of the hip (DDH) after closed reduction, assessing correlations between perfusion parameters and enhancement grades, and their utility in identifying post-reduction ischemia. Children with DDH undergoing closed reduction and plaster fixation were evaluated with MRI (conventional sequences, T1 mapping, and DCE-MRI) within 3days post-procedure. Femoral head perfusion was evaluated using DCE-MRI subtraction, graded as 0 (normal), 1 (asymmetric decrease), 2 (focal decrease), or 3 (complete decrease). Perfusion parameters (Ktrans, Kep, Ve) were quantified in the epiphyseal ROI. The correlation with perfusion grades and diagnostic value for ischemia was analyzed. The study included 58 DDH patients (116 hips; 68 dislocated, 48 normal). Among the dislocated side of DDH, although a marginal age difference was observed among the groups (P = 0.053), no significant differences were found in sex distribution or Tönnis grade (P > 0.05). Significant perfusion parameter differences were observed across enhancement grades (all P < 0.05), with Ktrans showing greatest discrimination (H = 89.769). Ktrans and Kep correlated negatively with enhancement grade (r = -0.883 and -0.608, respectively; both P < 0.001). For ischemia detection (grade ≥ 2), Ktrans demonstrated superior diagnostic accuracy (AUC = 0.959, cutoff = 0.028min-1) versus Kep (AUC = 0.811) and Ve (AUC = 0.628). Performance further improved for grade 3 ischemia (Ktrans AUC = 0.992, cutoff = 0.010min-1). Ktrans < 0.010min-1 on DCE-MRI signals post-reduction ischemia in dislocated femoral heads, inversely correlating with enhancement grade. This threshold may help identify high-risk patients requiring close monitoring or intervention.

The patellofemoral (PF) joint plays an integral role in knee biomechanics. Disorders of the PF joint are prevalent and a common source of anterior knee pain, particularly in younger and active patients. Abnormalities related to patellar tracking can lead to recurrent lateral patellar dislocation, early degenerative changes, and poor clinical outcomes if not detected and treated appropriately. Therefore, early recognition of PF instability is imperative to preserving joint function and improving long-term patient outcomes. Several alignment and morphological abnormalities are known risk factors that predispose patients to PF instability, including patellar malalignment, trochlear dysplasia, tibial tubercle lateralization, genu valgus, and rotational deformities. Imaging plays a key role in identifying these abnormalities and other osteoarticular and soft tissue pathology of the PF joint. Additionally, several quantitative measurements performed on imaging provide objective information on patellar alignment and tracking, further aiding clinicians with diagnosis and treatment planning. A consistent and standardized approach to the quantitative imaging evaluation of the PF joint is necessary for accurate reporting of measurements and imaging findings. This article highlights essential PF joint anatomy, current and evolving imaging techniques, and clinically relevant measurements for the evaluation of patients with suspected PF instability.

The acetabular cup version in patients with total hip arthroplasty (THA) is a key parameter influencing hip stability and functional outcomes. Although CT remains the reference standard for assessing cup orientation, MRI with metal artifact reduction techniques is increasingly used for evaluating postoperative pain. This study compared MRI- and CT-based measurements of acetabular cup version regarding agreement, reproducibility, and reliability. Patients who underwent THA between 2015 and 2025 with postoperative CT and MRI were retrospectively analyzed. MRI was performed using optimized metal artifact reduction sequences. Acetabular cup version was measured on axial high-bandwidth T1-weighted turbo spin-echo sequences and on corresponding CT scans by two musculoskeletal radiologists. Inter- and intra-reader, as well as inter-modality agreement, were assessed using intraclass correlation coefficients (ICC). Bland-Altman plots evaluated systematic bias. Thirty patients were included (mean age, 64.1years; 14 women). Mean acetabular version was 31.2° (standard deviation (SD), 9.4-10.3) for CT and 30.1-30.2° (SD, 8.9-9.3) for MRI for both readers. Inter-reader agreement was almost perfect for CT (ICC, 0.96) and substantial for MRI (ICC, 0.76). Intra-reader agreement was almost perfect for both modalities (ICC, CT, 0.99; MRI, 0.94). Bland-Altman analysis showed no statistically significant differences between CT and MRI measurements with a slight positive bias for MRI (mean pooled difference, 1.1°; p = 0.058; limits of agreement, -4.7 to 6.8°) and almost perfect agreement for both readers (ICC, 0.86-0.90). MRI measures acetabular cup version with excellent reliability and close agreement with CT, reinforcing MRI's role in postoperative THA evaluation.

Lateral discoid meniscus is the most common meniscal congenital variant. A lateral discoid meniscus manifests with a spectrum of findings, including abnormalities in size and shape, disorganized collagen architecture, and/or hypermobility, predisposing the meniscus to early degeneration and tearing. The purpose of this narrative review is to discuss the anatomy of the lateral discoid meniscus and to highlight MRI findings that should be included in radiology reports to guide management.

To evaluate whether femoral neck-parallel reconstruction of CT images improves the correlation with dual-energy X-ray absorptiometry for osteoporosis assessment compared with conventional table-parallel reconstruction. A retrospective analysis was conducted on 174 patients who underwent hip CT and dual-energy X-ray absorptiometry. Two CT image reconstruction methods were compared: femoral neck-parallel and table-parallel methods. CT values were extracted from cancellous bone regions in the femoral neck corresponding to the area measured by DXA. Correlation coefficients between CT values and dual-energy X-ray absorptiometry-derived bone mineral density and T-scores were calculated. A stratified analysis by femoral neck-to-table angle (< 5° vs. ≥ 5°) was performed. Receiver operating characteristic (ROC) curve analysis was performed to compare the ability of each method to discriminate between patients with and without low bone mass (defined as osteoporosis or osteopenia). CT values from the femoral neck-parallel method showed significantly stronger correlations with bone mineral density (r = 0.74) and T-score (r = 0.77) than those from the table-parallel method (bone mineral density: r = 0.66, T-score: r = 0.71) (p = 0.001 for both). In patients with ≥ 5° misalignment, the femoral neck-parallel method showed significantly higher correlation coefficients than the table-parallel method (bone mineral density, p < 0.001; T-score, p = 0.005). ROC curve analysis revealed that the area under the curve for detecting low bone mass was higher in the femoral neck-parallel method (0.87) than in the table-parallel method (0.83) (p = 0.012). Femoral neck-parallel reconstruction significantly improves the correlation between CT values and dual-energy X-ray absorptiometry for low bone mass assessment compared to table-parallel reconstruction.

To investigate the relationship between cartilage cap thickness, osteochondroma subtype (pedunculated vs. sessile), patient age, and multiple hereditary exostoses (MHE) diagnosis with malignant transformation of osteochondromas. A single-institution retrospective study of patients who underwent surgical excision of one or more osteochondromas between 1983 and 2025 was conducted. The relationship between cartilage cap thickness, osteochondroma subtype (pedunculated vs. sessile), patient age, and MHE diagnosis with malignant transformation was investigated. Among 1138 pathology-confirmed osteochondromas, 1097 (96.4%) were benign osteochondromas and 41 (3.60%) underwent malignant transformation. In tumors with a pathology-measured cartilage cap (n = 411), benign tumors (n = 397) had a smaller median cap size than malignant lesions (0.3cm [IQR: 0.2-0.6cm] vs. 3.15cm [IQR: 1.93-4.78cm]; p < .0001). Among 27 malignant cases with preoperative imaging, 63% were sessile and 37% pedunculated. Patients with benign tumors were younger than those with malignant transformations (27.1 ± 15.9 vs. 37.8 ± 12.2years; p < .0001). Patients with MHE had a greater incidence of malignant transformation compared to patients without (17% vs. 1.98%) (p < .0001). 137 MRIs and 37 CTs were compared to pathology measurements, yielding a concordance correlation coefficient of 0.80 and 0.92, respectively. The sensitivities and specificities were 29% and 91% for MRI and 67% and 94% for CT, respectively. A thicker cartilage cap, older age, and confirmed MHE diagnosis were each significantly associated with a higher rate of malignant transformation. Multidisciplinary teams should factor in a patient's clinical presentation and past medical history in addition to the tumor characteristics in deciding the proper course of treatment.

To evaluate the clinical impact of an artificial intelligence device, Rho, that opportunistically screens X-rays for low bone mineral density (BMD; DXA T-score < -1). Over 13months, Rho analyzed X-rays from patients ≥ 50years at a large independent health facility. Radiologists could opt to include Rho-flagged findings in their X-ray reports. DXAs that occurred within 6months of an X-ray (from patients in the first 7months of data collection) were categorized as being prompted by Rho ("Rho-generated") or arranged via usual standard-of-care practice ("pre-planned"), and their outcomes (diagnoses and 10-year fracture risk scores) were compared. Of 34,162 X-rays, Rho flagged 19,004 (56%) for low BMD, and radiologists included this information in 7726 (41%) reports. From the first 7months of radiologists reporting Rho findings, initial and surveillance DXAs increased by factors of 1.8 and 1.4, respectively. Of 299 Rho-generated DXAs, 193 had low bone mass (- 2.5 < T-score < - 1) and 65 had osteoporosis. Rho-generated DXAs vs. pre-planned DXAs identified a greater proportion of patients with low BMD (87% vs. 69%; p < 0.001) and similar proportions of patients with elevated fracture risk (34% vs. 40%). The diagnostic yield was particularly marked in patients undergoing their first-ever DXA (84% vs. 60%; p < 0.001), and in males ≥ 65years (83% vs. 45%; p < 0.001). Incorporating Rho in radiology workflow nearly doubled initial bone health assessments and prompted additional surveillance DXA evaluations. Rho-generated DXAs captured higher rates of true low BMD than standard-of-care practices, particularly in older men.