RPS 1610 - Imaging of the peripheral joints: shoulder to foot

Author Block: M. Curti, A. Cozzi, V. Chianca, S. Rizzo, F. Del Grande; Lugano/CH
Purpose: The insertion site of the coraco-glenoid ligament (CGL) of the shoulder seems to be involved in superior labrum anterior and posterior (SLAP) lesions. Anatomical and arthro-magnetic resonance imaging (MRA) studies have reported five CGL variants. This study aimed to evaluate inter-reader reliability in the identification of CGL presence and variants on 3-T MRA, also investigating potential associations between CGL variants and SLAP lesions.
Methods or Background: In this retrospective cohort study, three board-certified musculoskeletal radiologists (20, 10, and 5 years of experience) evaluated 1136 consecutive MRA examinations, 577 (50.2%) of patients with SLAP lesions. Inter-reader reliability in assessing CGL presence and variants was evaluated with Fleiss’ κ. After 1:1 patient matching according to age and sex, the association between the presence of SLAP lesions and CGL variants was evaluated with binary logistic regression, calculating odds ratios (ORs) and their 95% confidence intervals (CI).
Results or Findings: “Almost perfect” reliability was found for the identification of CGL variants (κ 0.832, 95% CI 0.813–0.851), the most frequent being type I (393/1136 patients, 34.6%), and type II (320/1136 patients, 28.2%). 1:1 matching resulted in two groups of 427 patients with and without SLAP lesions (256 males in each group; median age 52 years, IQR 44–59 years). Among these 854 matched patients, compared to the type I CGL variant, all other CGL variants had high ORs for the presence of SLAP lesions, ranging from OR 4.3 (95% CI 2.5–7.5) of type III to OR 39.9 (95% CI 24.5–65.0) for type II.
Conclusion: 3-T MRA grants high reliability in identifying CGL presence and variants. In an age and sex matched comparison, the type II CGL variant was strongly associated with the presence of SLAP lesions.
Limitations: Single-center study
Funding for this study: None
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Local etichs commitee

Author Block: A. Fujii, M. Katsumata, C. Sato, S. Tsukahara, T. Wada, M. Yamamoto, H. Kondo, H. Oba, A. Yamamoto; Tokyo, Japan/JP
Purpose: Non-traumatic myositis ossificans (MO) in the pelvic region in patients with neurological disorders are classically reported on radiographs. However, CT findings have been rarely reported and the time-course has not been proven. The purpose is to investigate the patients’ background, CT findings and the time-course of MO involving the short external rotator muscles (SERMs) of the hip.
Methods or Background: Of patients hospitalized for acute cerebrovascular disease between 2001 and 2023 in our hospital, 1,469 CT scans were performed for 436 patients. Swelling, calcification and ossification of SERMs, evaluated for each hip by two radiologists, were judged as calcification when the average density of the lesion was above 100HU, and as ossification when bone marrow fat was confirmed. Medical charts were reviewed for their clinical course and neurological findings.
Results or Findings: SERMs swelling was found in 22 cases, 29 hips (age 61.0±3.0, 9 males, 13 females). Follow-up CT scans were examined in 6 (6/436, 1.4%) (aged 35–72, mean 54.7±12.7, 2 male, 4 female). All showed ipsilateral limb paralysis due to cerebral hemorrhage. Swelling was detected in 8 hips of 6 patients, 4 unilaterally (right:left, 3:1) and 2 bilaterally. Follow-up CT revealed calcification in all swelling lesions in SERMs . The post-onset time-course in 6 hips was 13–36 days for swelling, 23–53 days for calcification, and 49–360 days for ossification. In 2 hips, calcification disappeared on follow-up CT.
Conclusion: CT imaging illustrated the drastic changes in the maturation process of SERMs-MO. Understanding the time-course of SERMs-MO is essential in the management, and frequency of follow-up CT for distinguishing neoplasms and infectious conditions.
Limitations: This was a retrospective study of a few patients. The follow-up durations varied between patients because examinations of the lesions were not always performed.
Funding for this study: No funding was received for this study.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The study was approved by Teikyo University Medical Research Ethics Committee(23-030).

Author Block: L. D. Grünewald, V. Koch, S. Mahmoudi, S. Martin, J-E. Scholtz, I. Yel, C. Booz, T. Vogl; Frankfurt/DE
Purpose: Distal radius fractures (DRF) are commonly diagnosed in emergency departments. Depending on fracture characteristics and patient factors, bone substitutes may be needed, a decision usually made during surgery. However, preoperative preparations, such as obtaining informed consent, are necessary. This study aimed to evaluate metrics from routine CT scans as surrogates for bone texture to predict bone substitute use in surgery.
Methods or Background: Distal radius scans of patients who underwent dual-energy CT (DECT) between 01/2016 and 08/2021 were retrospectively analyzed. Cortical HU, trabecular HU, cortical thickness, and DECT-based bone mineral density (BMD) were measured. Patient records and follow-up images were reviewed to determine bone substitute use during surgery. Receiver-operating characteristic (ROC) analysis identified AUC values for BMD, HU values, and cortical thickness, while logistic regression assessed their association with bone substitute use.
Results or Findings: A total of 263 patients (median age, 52 years; 132 women; 192 fractures) were included. ROC analysis showed a higher AUC for DECT-derived BMD compared to cortical HU, trabecular HU, and cortical thickness (0.87 vs. 0.62, 0.52, and 0.60, respectively; P < .001). Logistic regression confirmed a significant association between lower DECT-derived BMD and the use of bone substitutes (Odds Ratio, 0.94; P = .02), while cortical HU, trabecular HU, and cortical thickness were not significantly associated (P > .05).
Conclusion: Routine CT scans of the distal radius can predict the use of bone substitutes in DRF surgical management, facilitating preoperative planning. DECT-derived BMD offers superior predictive performance compared to cortical HU, trabecular HU, and cortical thickness.
Limitations: Preselection bias, as patients received Xrays before CT.
Funding for this study: No funding was received for this study
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Consent waived due to the retrospective nature of the study

Author Block: S. Rajan, J. S. Chatha, H. Mahajan; New Delhi/IN
Purpose: Purpose: Recalcitrant lateral epicondylitis, often presents diagnostic challenges, particularly in ruling out symptomatic micro-instability in the lateral elbow (SMILE lesion). This study aims to evaluate the radiological findings in a retrospective cohort, focusing on defining MRI findings with arthroscopically confirmed SMILE lesions.
Methods or Background: Methods: A total of 313 consecutive elbow MRIs referred for tennis elbow of which 7 arthroscopically proven cases of SMILE lesions were identified as test cases, and key imaging findings were documented as a checklist. The remaining 306 cases were randomized and anonymized and analyzed by two experienced radiologists (9 and 22 years of experience). On MR, key findings included lateral ulnar collateral ligament (LUCL) tear, partial tear of the extensor carpi radialis brevis (ECRB), widened ulnotrochlear joint or radiocapitellar posterior shift . Statistical significance of findings was assessed using Chi-square tests for categorical variables and Fisher's exact test for small sample sizes.
Results or Findings: Results: Of the 306 evaluated cases, 122 (25.8%) showed partial LUCL tears, 12 (3.9%) had complete LUCL tears, 268 cases (87.5%). had deep surface partial tears of ECRB. Statistical analysis revealed a significant association between the presence of LUCL tears (partial and complete) and abnormal radiocapitellar alignment (p < 0.01). Abnormal ulnotrochlear alignment was significantly associated with the presence of ECRB tears (p < 0.05). Intra-articular abnormalities included posterior radial synovial plica in 22 cases (7.18%), synovitis in 3 cases (0.98%), and chondral lesions in the radial head in 39.78% of cases, with minimal occurrence of lateral capitellar lesions (0.65%).
Conclusion: Conclusions: The study underscores a significant association between MRI findings such as LUCL tears, ECRB injuries, and joint misalignments.
Limitations: Arthroscopic proof was not available in the cases. MR arthrography could possibly have helped.
Funding for this study: None
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information: Retrospective study using HIPAA guidelines

Author Block: W. Xiong¹, J. Han², G. Zhang², T. Wang², M. Cheng¹, L. Hu¹, W. Li¹, Z. Ding¹, X. He¹; ¹Nanchang/CN, ²Shanghai/CN
Purpose: To evaluate the diagnostic performance of dual-energy CT (DECT) with water-calcium and water-hydroxyapatite (HAP) material decomposition for quantitatively detecting and differentiating bone marrow edema (BME) in knee.
Methods or Background: This retrospective study included 26 patients who underwent DECT and magnetic resonance imaging (MRI) on the same day for the knee. The DECT images were post-processed to generate water-calcium and water-HAP material decomposed images, on which two readers independently measured the water mass density of edema zone and contralateral normal bone marrow by drawing ellipse regions of interest. The MRI was served as the reference for presence and extent of BME. The edema extent was graded as mild or severe by visual assessment. The diagnostic performance of DECT was evaluated using the receiver operating characteristic (ROC) analysis.
Results or Findings: Thirty-two bones were confirmed with BME at MRI, caused by fractures (n=16), arthritis (n=10) and bruises (n=6). The mean water mass density of severe BME, mild BME and normal bone marrow was 1073.9 ± 15.2, 1052.9 ± 13.0, and 1012.5 ± 22.4 mg/cm3 (p <0.001), respectively, on water-calcium images; and 1012.9 ± 15.6, 979.7 ± 23.8, and 959.1 ± 12.8 mg/cm3 (p <0.001), respectively, on water-HAP images. In detecting the presence of BME, the area under the ROC curve (AUC) of water-calcium and water-HAP images was 0.976 and 0.885 (p = 0.001), respectively, and the accuracy was 89.1% and 79.7%. In differentiating severe and mild BME, the AUC of the two decomposed images was 0.836 and 0.896 (p = 0.318), respectively, with accuracy of 70.3% and 87.5%.
Conclusion: Dual-energy CT with water-calcium decomposition showed superior diagnostic performance for quantitatively detecting BME in knee, while water-HAP decomposition showed better performance in differentiating severe and mild BME.
Limitations: Not applicable.
Funding for this study: No funding was received for this study.
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information: This study was a retrospective study.

Author Block: T. C. Arnold, L. Wang, L. Yao, A. Shankaranarayanan, S. Pasumarthi Venkata; Menlo Park, CA/US
Purpose: Knee MRI protocols acquire multiple acquisition planes for three main 2D sequences: T1w, T2w, and PD. However, protocol sequence number is limited by time constraints, meaning some contrast and orientation combinations are not available. Here, we develop a deep-learning-based method to synthesize 2D sequences using complementary contrast and acquisition plane information from two input images, and quantitatively compare synthesized and ground truth acquisitions
Methods or Background: We retrospectively analyzed data from 50 knee MRI participants. Each contained three 2D sequences: axial T2 fat-sat, coronal T2 fat-sat, and coronal PD. The coronal T2 fat-sat served as our target sequence and the remaining sequences were our network inputs. All images were coregistered to the target image. Patients were divided into training (N=34), validation (N=8), and testing (N=8) sets. Quantitative metrics (PSNR, SSIM, and NMI) measured the similarity between the synthesized coronal T2 and acquired images.
Results or Findings: The algorithm demonstrated excellent quantitative performance when comparing acquired and synthesized coronal T2 fat-sat images across all three metrics (SSIM: 0.86±0.13, PSNR: 29.98±5.93 dB, and NMI: 1.33±0.10). We also compared the synthesized images to a coronal reformat of the acquired axial T2 fat-sat (SSIM: 0.68±0.22, PSNR: 23.33±5.21 dB, and NMI: 1.21±0.10) to illustrate the significant benefit of our algorithm over simple image reformation (paired t-test, SSIM: p<0.005, PSNR & NMI: p<0.001). Relative to simple reformats, the synthesized image showed a 26% SSIM increase, 29% PSNR increase, and 10% NMI increase. Qualitatively, pathological presentation in the synthesized image was similar to acquired sequences.
Conclusion: This study presents a deep-learning-based method to synthesize high quality multiplanar reformations in knee MRI. Synthesized images exhibited strong quantitative similarity to acquired images.
Limitations: In future work, these methods should undergo qualitative review by radiologists.
Funding for this study: This study was funded by Subtle Medical.
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information: All data was retrospective and anonymized and therefore not considered human subjects research.

Author Block: N. Giannotti¹, A. Liu², H. Gauffin², S. Filbay³, J. Kvist², M. Englund⁴; ¹Sydney/AU, ²Linköping/SE, ³Melbourne/AU, ⁴Lund/SE
Purpose: Anterior cruciate ligament (ACL) injuries are common, and ACL reconstruction (ACLR) is considered vital for restoring knee stability. However, recent evidence evaluating non-surgical approaches to the injured ACL challenges these notions. To date, no studies have used three-dimensional magnetic resonance imaging (3D-MRI) to systematically assess morphological changes of the injured ACL at different time-points in non-reconstructed patients. The aim of this study was to develop and investigate the reliability of a semi-quantitative scoring system to assess morphological changes of the injured ACL using 3D-MRI.
Methods or Background: Baseline and 4 follow-ups within 2 years 3T 3D-MRI scans were acquired with an isotropic proton-density fat-saturated sequence. Scans were censored from further analysis after ACLR. 3D-MRI data were reconstructed on oblique coronal parallel to ACL, sagittal, and axial planes. Unblinded for time sequence, two readers independently scored the MRI data from all available time-points. The intra-rater reliability was measured six months after the initial evaluation. Weighted kappa (κw) was used to calculate inter- and intra-reader reliability.
Results or Findings: 129 patients (46% female; 25 SD [7] years) with non-surgically treated ACL injury from the NACOX study were included. The scoring system developed assessed the following ACL 3D-MRI features: overall structure, fiber continuity, thickness, and shape. The injury location was scored at baseline. 2,430 gradings were collected in total. The averaged inter-reader reliability (κw) was 0.738, 0.673, 0.710 and 0.539 for ligament structure, fiber continuity, thickness and shape, respectively. The intra-rater reliability (κw) ranged from 0.409 to 0.873.
Conclusion: We introduce a novel 3D-MRI-based semi-quantitative scoring system to enable assessment of the acutely injured ACL and its morphological changes over time with acceptable inter-reader reliability. Future validation vs findings from knee arthroscopy will be required.
Limitations: No limitations were identified.
Funding for this study: The NACOX study received funding from the Swedish Research Council, Medical Faculty of Linköping University, Swedish National Centre for Research in Sports, Medical Research Council of Southeast Sweden (FORSS), ALF Region Östergötland
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Ethical approval for the study was granted by the Swedish Ethical Review Authority, Dnr: 2016/44/31.

Author Block: M. V. Bausano¹, F. Di Maria², R. D'Ambrosi¹, L. M. Sconfienza¹, S. Fusco¹, E. Abermann³, C. Fink³; ¹Milan/IT, ²Catania/IT, ³Innsbruck/AT
Purpose: The aim was to assess the posterior cruciate ligament (PCL) angle in anterior cruciate ligament deficient knees and correlate it with anatomic and demographic factors.
Methods or Background: Patients included were initially noted to have an ACL tear clinically as confirmed by MRI.For each patient were evaluated:PCL angle (PCLA), medial tibial slope(MTS), lateral tibial slope(LTS), medial anterior tibial translation(MATT) and lateral anterior tibial translation(LATT).Age,sex,and time from injury to MRI were manually recorded.Age groups were predefined dichotomizing age at its mean value while for time interval from injury to MRI the cut-off of 90 days was selected to differentiate between chronic and acute lesions.Differences by groups were assessed with t-test or a Wilcoxon-Mann Whitney test,according to score distribution.Spearman rank correlations were also estimated to explore correlation among collected variables.
Results or Findings: A total of 193 patients were included in the study of which 91 females and 102 males with a mean age of 30.27±12.54.The mean time from injury to MRI was 14.18±55.77 days.On overall population, mean PCLA resulted 128.72±10.33°, mean MTS 3.57±2.33, mean LTS 6.07±3.52, mean MATT and LATT were respectively 4.76±2.02 and 7.01 ±2.48 mm. In 190 cases PCLA angle was≥to 105° and only in 3 was inferior.PCLA negatively correlated with medial and lateral anterior tibial translation(p<0.05).Female showed a higher PCLA compared to male(130.55±10.23vs127.08±10.20;p=0.019).Patients with chronic ACL injury showed a lower value of PCLA compared to patients with acute injury(p=0.032)and a superior grade of LATT(p=0.015).
Conclusion: In the setting of ACL lesions, PCLA has normal value in acute injury and decrease over the time. PCLA is negatively correlated with anterior tibial translation and female have higher PCLA compared to male.
Limitations: First, the diagnosis was made exclusively by MRI analysis, second the data excluded partial ACL injuries.
Funding for this study: N/A
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: After Institutional Review Board approval (ACL-L2104), two of the authors reviewed the MR images of all patients with a clinical diagnosis of acute ACL injury.
The present study was conducted following the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement [3]. All procedures were conducted in accordance with the standards highlighted in the 1964 Helsinki Declaration and its later amendments.

Author Block: S. N. Yılmazer Zorlu, N. A. Ahmady, K. B. Karaca, Z. Akkaya; Ankara/TR
Purpose: To investigate the relationship between meniscal height and adjacent synovitis on magnetic resonance images (MRI) of the knee, based on the hypothesis that, in contrast to simple effusion, hypertrophic synovial tissue will cause compressive distortion on neighboring meniscus.
Methods or Background: Contrast-enhanced knee MRIs from patients (≥18years), acquired during 2014-2024, at a single university hospital were included in this cross-sectional, retrospective study. Patients with history of knee surgery, acute trauma, local and systemic malignancy were excluded. On post-contrast fat-suppressed(fs)-T1-weighted images, 2 independent observers assessed the presence of synovitis (synovial enhancement ≥2mm) adjacent to the medial meniscus body-posterior horn (MMB, MMPH) and lateral meniscus body-posterior horn (LMB, LMPH). Blinded to the synovitis status, meniscal heights were measured on coronal and sagittal fs-fluid sensitive images where menisci were intact and showed < grade 2 degeneration. The relationship between meniscal height and synovitis was evaluated using linear regression models adjusted for age, gender and body mass index (BMI). Intra-class correlations (ICC) were used to test the reproducibility of meniscal height measurements across 10 randomly selected patients.
Results or Findings: A total of 129 patients (85 women, mean age=46.6±15years, mean BMI=24.6±5.1 kg/m2) (119 patients on 1.5T; 10 patients on 3.0T systems; ranges of slice thickness=3.5-6mm, gap=0.3-1mm, FOV=12-16 cm) were included. Mean heights of MMB, MMPH, LMB, LMPH were 5.5±1mm, 5.3±1.1mm, 5.9±0.9mm, 5.6+0.8mm, respectively. MMB, MMPH and LMPH were significantly thinner adjacent to synovitis regions(β=-0.9, [95%CI= -1.34, -0.44], p<0.001; β=-1.26, [95%CI=-1.79, -0.73], p<0.001; β=-0.7, [95%CI= -1.12, -0.29], p=0.001, respectively). ICC ranged between 0.96 - 0.99 (p<0.001), indicating excellent inter-rater agreement.
Conclusion: Diminished meniscal height adjacent to high-signal areas on fluid-sensitive images may help distinguish effusion from synovitis on clinical knee MRIs.
Limitations: The BMI values were not available in 25 patients.
Funding for this study: None
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Ethics Committee Approval Number: I03-251-24

Author Block: M. Acke¹, B. Keelson¹, L. H. W. Engseth², G. Van Gompel¹, F-D. Ohrn³, J. De Mey¹, A. Schulz², S. M. Röhrl², N. Buls¹; ¹Brussels/BE, ²Oslo/NO, ³Kristiansund/NO
Purpose: The current gold-standard for implant migration analysis is radiostereometric analysis (RSA), which is a time-consuming and resource demanding method.
We aim to evaluate the precision of a novel non-invasive method using automated CT-based radio-stereometric analysis (CT-RSA) for tibial implant migration analysis in a porcine model.
Methods or Background: A porcine knee cadaver with a tibial implant was examined with marker-based RSA and computed tomography (CT).
RSA acquisitions (133kV, 6.3mAs) and CT images (120kV, 100mAs, 0.625mm, 0.5s, FOV 200×200mm) were acquired in seven different positions (P1,…,P7) of the cadaveric knee. To obtain enough statistical power, the 7 positions were compared to each other, resulting in 21 double examinations (P1_P2,…,P6_P7) for each method. Post-processing of the CT data was performed by a novel in-house built automatic image processing pipeline using SimpleITK. The reference standard was zero implant motion.
Maximum-Total-Point-Motion (MTPM) was calculated for RSA to identify the implant point with maximum translation. Similarly, from the CT-RSA data we calculated Total-Translation (TT) for 6 non-invasive, virtual landmarks on the implant, including the centre-of-mass and 5 peripheral landmarks. In addition, we computed a virtual implant mesh from the CT data, including its displacement. For RSA and CT-RSA, displacement differences towards the reference-standard were assessed using a two-sample t-test.
Results or Findings: The precision for MTPM using marker-based RSA was 0.45mm (95%CI 0.19–0.70mm). TT calculation for virtual landmarks using CT-RSA was more precise than RSA (p<0.001) with 0.15mm (95%CI 0.12–0.18mm). The mesh data allowed to identify the point of maximum translation with a displacement of 0.16mm (95%CI 0.13–0.19mm).
Conclusion: Compared to RSA, the novel automated CT-RSA shows improved precision in analysing tibial implant migration for a porcine cadaver.
Limitations: This is a porcine phantom-study, which limits generalizability and results may differ in humans.
Funding for this study: Funding is provided by the UZBrussels, Belgium and CIRRO, Norway.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The study was approved by the local research committee at Oslo University Hospital on December 13, 2021. No consent was necessary since exams were performed on a porcine cadaver phantom.

Author Block: E. Mcdermott, D. P. Moloney, S. Murphy, B. Gibney, P. J. Macmahon, E. Kavanagh; Dublin/IE
Purpose: Foot trauma is a common presentation to the emergency department. In our institution Cone Beam Computed Tomography (CBCT) is routinely utilized in patients with suspected fractures with negative radiographs. Previous studies have investigated the role of CBCT in the acute trauma setting for wrist and ankle injuries, but no large study has been performed for foot trauma. Our study focuses on how CBCT can improve the diagnosis of foot fractures in a trauma setting and, with the input of orthopaedic surgery, how it can alter the patient’s treatment plan.
Methods or Background: Patients with foot trauma who underwent CBCT between 2019 and 2023 were reviewed. In cases of discordance between CBCT and X-rays, images were assessed with an orthopaedic surgeon. Patients were classified into three treatment options based on X-rays and CBCT: No Treatment, Immobilisation, and Surgery.
Results or Findings: 204 trauma patients had foot X-rays and CBCT. In 102 cases, CBCT identified 164 additional fractures, leading to treatment changes in 62 cases (p < 0.01). 42 changed from ‘No Treatment’ to ‘Immobilisation,’ 3 from ‘No Treatment’ to Surgery,’ and 3 from ‘Immobilisation’ to ‘Surgery.’ 12 were downgraded from ‘Immobilisation’ to ‘No Treatment,’ and 2 from ‘Surgery’ to ‘Immobilisation’.
Conclusion: Our findings show that a large number of foot trauma goes un-diagnosed on radiographs. The involvement of orthopaedic surgery in reviewing the radiographs and CBCT to assess how treatment plans may change is a novel approach. We found that a significant number of patients would have their type of treatment altered with the use of CBCT. Our findings show the significant role CBCT can have when integrated into trauma care.
Limitations: Only a single centre was used for data collection. Reporting of initial radiographs by non-musculoskeletal specialised radiologists.
Funding for this study: None.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Project approved by the Mater Misericordiae University Hospital's Clinical Audit and Effectiveness Committee.