Skeletal Radiology最新文献

A 81-year-old woman with chronic periprosthetic knee infection underwent implantation of a temporary articulating PROSTALAC spacer following prosthesis removal. Over the ensuing 3 months, she developed worsening mechanical symptoms including instability, clicking, and difficulty bearing weight. Radiographs and MRI demonstrated a transverse fracture through the femoral component of the spacer with cement fragmentation and malalignment. Revision surgery with replacement of the fractured spacer led to resolution of symptoms and improved postoperative function. This case highlights the limited structural durability of polymethylmethacrylate (PMMA)-based articulating spacers during prolonged implantation and emphasizes the importance of imaging evaluation when new mechanical symptoms arise.

Objective: 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.

Materials and methods: Children with DDH undergoing closed reduction and plaster fixation were evaluated with MRI (conventional sequences, T1 mapping, and DCE-MRI) within 3 days 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 (K^trans, K_ep, V_e) were quantified in the epiphyseal ROI. The correlation with perfusion grades and diagnostic value for ischemia was analyzed.

Results: 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 K^trans showing greatest discrimination (H = 89.769). K^trans and K_ep correlated negatively with enhancement grade (r = -0.883 and -0.608, respectively; both P < 0.001). For ischemia detection (grade ≥ 2), K^trans demonstrated superior diagnostic accuracy (AUC = 0.959, cutoff = 0.028 min^-1) versus K_ep (AUC = 0.811) and V_e (AUC = 0.628). Performance further improved for grade 3 ischemia (K^trans AUC = 0.992, cutoff = 0.010 min^-1).

Conclusion: K^trans < 0.010 min^-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.

Objective: 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.

Materials and methods: 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.

Results: 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.

Conclusion: 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.

Longitudinal skeletal growth occurs at the physis by a continuous process of chondrocyte division and hypertrophy. The physes of the distal femur and proximal tibia are the main contributors to skeletal growth, and therefore physeal abnormalities are most consequential in the knee. The normal growth structures are well depicted by conventional MR imaging, which demonstrates the integrity of the physeal cartilage, zone of provisional calcification, and primary spongiosa. Insults to the physeal cartilage including trauma, infection, chronic nonbacterial osteomyelitis, and repeated stress are also well depicted by sequences that show discontinuity of the cartilage and zone of provisional calcification. The dreaded complication of these physeal disturbances is the formation of a physeal bar, a bridge of tissue, generally bone, that joins the epiphyseal and metaphyseal bone and tethers growth. MRI shows the size of the abnormality of the physis as well as its location and depicts the abnormal growth by showing abnormal orientation of the growth recovery lines. Abnormal growth activity can be shown by diffusion tensor imaging tractography and quantified by metrics such as tract volume, apparent diffusion coefficient (ADC) and fractional anisotropy (FA).

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.

Objective: 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.

Material and methods: 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.

Results: Thirty patients were included (mean age, 64.1 years; 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).

Conclusion: 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.

Objective: 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.

Materials and methods: 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).

Results: 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).

Conclusions: 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.