Experienced Musculoskeletal Radiologist Research Articles

Artificial Intelligence Quantification of Enhanced Synovium Throughout the Entire Hand in Rheumatoid Arthritis on Dynamic Contrast-Enhanced MRI.

Challenges persist in achieving automatic and efficient inflammation quantification using dynamic contrast-enhanced (DCE) MRI in rheumatoid arthritis (RA) patients. To investigate an automatic artificial intelligence (AI) approach and an optimized dynamic MRI protocol for quantifying disease activity in RA in whole hands while excluding arterial pixels. Retrospective. Twelve RA patients underwent DCE-MRI with 27 phases for creating the AI model and tested on images with a variable number of phases from 35 RA patients. 3.0 T/DCE T1-weighted gradient echo sequence (mDixon, water image). The model was trained with various DCE-MRI time-intensity number of phases. Evaluations were conducted for similarity between AI segmentation and manual outlining in 51 ROIs with synovitis. The relationship between synovial volume via AI segmentation with rheumatoid arthritis magnetic resonance imaging scoring (RAMRIS) across whole hands was then evaluated. The reference standard was determined by an experienced musculoskeletal radiologist. Area under the curve (AUC) of receiver operating characteristic (ROC), Dice and Spearman's rank correlation coefficients, and interclass correlation coefficient (ICC). A P-value <0.05 was considered statistically significant. A minimum of 15 phases (acquisition time at least 2.5 minutes) was found to be necessary. AUC ranged from 0.941 ± 0.009 to 0.965 ± 0.009. The Dice score was 0.557-0.615. Spearman's correlation coefficients between the AI model and ground truth were 0.884-0.927 and 0.736-0.831, for joint ROIs and whole hands, respectively. The Spearman's correlation coefficient for the additional test set between the model trained with 15 phases and RAMRIS was 0.768. The AI-based classification model effectively identified synovitis pixels while excluding arteries. The optimal performance was achieved with at least 15 phases, providing a quantitative assessment of inflammatory activity in RA while minimizing acquisition time. 3 TECHNICAL EFFICACY: Stage 2.

Fully automatic quantification for hand synovitis in rheumatoid arthritis using pixel-classification-based segmentation network in DCE-MRI.

A classification-based segmentation method is proposed to quantify synovium in rheumatoid arthritis (RA) patients using a deep learning (DL) method based on time-intensity curve (TIC) analysis in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). This retrospective study analyzed a hand MR dataset of 28 RA patients (six males, mean age 53.7years). A researcher, under expert guidance, used in-house software to delineate regions of interest (ROIs) for hand muscles, bones, and synovitis, generating a dataset with 27,255 pixels with corresponding TICs (muscle: 11,413, bone: 8502, synovitis: 7340). One experienced musculoskeletal radiologist performed ground truth segmentation of enhanced pannus in the joint bounding box on the 10th DCE phase, or around 5min after contrast injection. Data preprocessing included median filtering for noise reduction, phase-only correlation algorithm for motion correction, and contrast-limited adaptive histogram equalization for improved image contrast and noise suppression. TIC intensity values were normalized using zero-mean normalization. A DL model with dilated causal convolution and SELU activation function was developed for enhanced pannus segmentation, tested using leave-one-out cross-validation. 407 joint bounding boxes were manually segmented, with 129 synovitis masks. On the pixel-based level, the DL model achieved sensitivity of 85%, specificity of 98%, accuracy of 99% and precision of 84% for enhanced pannus segmentation, with a mean Dice score of 0.73. The false-positive rate for predicting cases without synovitis was 0.8%. DL-measured enhanced pannus volume strongly correlated with ground truth at both pixel-based (r = 0.87, p < 0.001) and patient-based levels (r = 0.84, p < 0.001). Bland-Altman analysis showed the mean difference for hand joints at the pixel-based and patient-based levels were -9.46 mm3 and -50.87 mm3, respectively. Our DL-based DCE-MRI TIC shape analysis has the potential for automatic segmentation and quantification of enhanced synovium in the hands of RA patients.

Comparison of the diagnostic performance of the Swischuk line method and the anterior atlantodental interval method in atlantodental subluxation.

Atlantodental subluxation (ADS) is a serious condition that can result in sudden death. Measuring the anterior atlantodental interval (AADI method) is the gold standard for diagnosis but the complex anatomy of this region can make diagnosis difficult, especially for beginners. Therefore, we would like to use a simpler method, the Swischuk line method, to diagnose ADS. The purpose of our study was to evaluate the diagnostic performance of the Swischuk line method for ADS on lateral cervical spine radiographs compared to the AADI method. A retrospective study was conducted with patients who presented with ADS (ADS group, n = 32, mean age 57.78 years, age range 34-82 years, 10 men, 21 women) and an age- and sex-matched control group (n = 32). The diagnostic performance of the AADI method and the Swischuk line method for ADS was assessed using lateral cervical radiographs in both flexion and neutral postures by an experienced musculoskeletal radiologist (reader 1), a senior resident (reader 2), and a junior resident (reader 3) in the radiologic department. In the flexion posture, the AADI method and the Swischuk line method showed excellent diagnostic performance with AUCs > 0.9 for readers 1 2 and reader 3. In a neutral posture, the diagnostic performance of the AADI and Swischuk line methods was decreased. With a 1mm cut-off value using the Swischuk line method in flexion posture, the sensitivity was 75% or more, the specificity was 100%, and the accuracy was 87.50% or more 90.63% for all readers. With a 2mm cut-off value, the sensitivity was low (37.50-46.88%) but the specificity was 100% for all three readers. In a neutral posture, the sensitivity for both methods decreased, though specificity remained high (> 80%). The Swischuk line method was found to be reliable and showed high sensitivity and specificity with a cut-off value of 1mm for the diagnosis of ADS in cervical lateral radiographs in flexion posture. It can be used as a complement to the AADI method.

Interobserver reliability of classifying shoulder calcific tendinopathy on plain radiography and ultrasound

Introduction: Shoulder calcific tendinopathy is a frequent cause of shoulder pain. Diagnosis is usually based on ultrasound (US) and/or x-ray. US is considered an inherently operator-dependent imaging modality and, interobserver variability has previously been described by experts in the musculoskeletal US. The main objective of this study is to assess the interobserver agreement for shoulder calcific tendinopathy attending to the size, type, and location of calcium analyzed in plain film and ultrasound among trained musculoskeletal radiologists.Material and methods: From June 2018 to May 2019, we conducted a prospective study. Patients diagnosed with shoulder pain related to calcific tendinopathy were included. Two different experienced musculoskeletal radiologists evaluated independently the plain film and the US.Results: Forty patients, with a mean age of 54.6 years, were included. Cohen´s kappa coefficient of 0.721 and 0.761 was obtained for the type of calcium encountered in plain film and the US, respectively. The location of calcification obtained a coefficient of 0.927 and 0.760 in plain film and US, respectively. The size of the calcification presented an intraclass correlation coefficient (ICC) of 0.891 and 0.86 in plain film and US respectively. No statistically significant differences were found in either measurement.Conclusion: This study shows very good interobserver reliability of type and size measurement (plain film and US) of shoulder calcifying tendinopathy in experienced musculoskeletal radiologists.Level of Evidence: III, prospective inter-observer study

Single-Plane 3-Dimensional Isotropic Spin-Echo Magnetic Resonance Imaging Reconstructions of Shoulder Exhibit Superior Correlation to Surgical Findings Than 2-Dimensional Dixon Multiplanar Magnetic Resonance Imaging.

The aim of the study is to evaluate concordance of multiplanar 2-dimensional magnetic resonance imaging (2D-MRI) versus 3D isotropic MRI for rotator cuff and labral tears with the reference standard of arthroscopic surgical findings. It was an institutional review board-approved retrospective single-center study of consecutive preoperative patients with isotropic 3D-MRI on 3-Tesla scanners, multiplanar 2D-MRI, and shoulder arthroscopy. Scapular plane-oriented contiguous multiplanar reconstructions of 3D-images were evaluated by 2 experienced fellowship-trained musculoskeletal radiologists. Variables included the following: labral tear presence and rotator-cuff tear Ellman grade, thickness, and width. Sensitivities (Sen) and specificities (Spe) were calculated for binary variables. Mean squared errors (MSE) were calculated for ordinal variables. Lower MSE indicated higher concordance. Seventy-two patients (43 female) with a mean age of 50.75 ± 9.76 years were evaluated. For infraspinatus-tear presence, 3D-MRI showed higher sensitivity (0.96) and specificity (0.68) than 2D-MRI (Sen = 0.85, Spe = 0.32) ( Psen = 0.005, Pspe = 0.002). For subscapularis-tear presence, 3D-MRI showed higher sensitivity (0.94) and specificity (0.73) compared with 2D-MRI (Sen = 0.83, Spe = 0.56) ( Psen = 0.02, Pspe = 0.04). For supraspinatus-tear presence, there was no significant difference between 3D-MRI (Sen =0.96, Spe = 0.67) compared with 2D-MRI (Sen = 0.98, Spe = 0.83) ( Psen = 0.43, Pspe = 0.63). For infraspinatus-tear thickness, 3D-MRI showed lower MSE (0.35) compared with 2D-MRI MSE (0.82) ( P = 0.01). For subscapularis-tear thickness, 3D-MRI had lower MSE (0.31) compared with 2D-MRI MSE (0.51) ( P = 0.007). However, no difference noted for supraspinatus-tear thickness when comparing 3D-MRI MSE (0.39) and 2D-MRI MSE (0.51) ( P = 0.49). For labral-tear presence, 3D-MRI had a lower MSE (0.20) compared with 2D-MRI MSE (0.57) ( P < 0.001). Three-dimensional MRI of the shoulder is time efficient with a shorter acquisition time and exhibits comparable with superior correlation to surgical findings than 2D-MRI for detection of labral tears and some rotator cuff tears. Three-dimensional MRI may be used in place of traditional 2D-MRI in detection of soft-tissue shoulder injury in centers equipped to do so.

Abnormalities of the pericruciate fat pad: Correlations with the location and severity of chondral lesions of the knee

PurposeThe aim of this study was to evaluate the relationship between the grade of signal change of the pericruciate fat pad (PCFP) and the location and severity of cartilage alterations in the knee on magnetic resonance imaging (MRI). Materials and methodsThis retrospective study included 234 patients (M:F = 96:138, mean: 51 years) who underwent knee MRI. Two experienced musculoskeletal radiologists assessed any PCFP alterations (as grades 0–3) and chondral lesions using the modified Outerbridge grade (as grades 0–4). Bone marrow lesions (BMLs), meniscal status, anterior cruciate ligament alterations, and effusion-synovitis were also evaluated on the MRI. The relationships between PCFP alteration and MR findings (including the grade of chondral lesion) were evaluated. ResultsSignal changes in the PCFP were detected in 150 cases by Reader 1 (grade 0, 67 cases; grade 1, 53 cases; grade 2, 21 cases; grade 3, 9 cases) and in 154 cases by Reader 2 (grade 0, 59 cases; grade 1, 61 cases; grade 2, 24 cases; grade 3, 10 cases). The grade of PCFP signal change was statistically significantly correlated with the grade of the chondral lesion of the medial femoral condyle (MFC) (p = 0.029 and p = 0.003, respectively) and the medial tibial plateau (MTP) (p = 0.045, p = 0.002, Readers 1 and 2, respectively). The grade of PCFP signal change was significantly correlated with the grade of the BMLs of the MFC, MTP, and lateral femoral condyle (p < 0.05) for both readers. PCFP alteration was related to effusion-synovitis and tears of the medial meniscus. ConclusionsThe grade of PCFP signal change was correlated with the severity of the cartilage alteration in the medial compartment of the knee joint and was also correlated with BMLs in the medial compartment, medial meniscal tears, and synovitis. Therefore, signal change in the PFCP seen on MRI can be an additional clue of the presence of osteoarthritis in the knee, particularly in the medial compartment.

Early Identification of Sacroiliitis in Patients with Suspected Spondyloarthritis: A Challenging Task.

The purpose of this study was to assess the performance of computed tomography (CT) scan and magnetic resonance imaging (MRI) for detecting sacroiliitis in nonradiographic SpA (nr-SpA). This cross-sectional monocentric double-blind study included 63 patients consulting for symptoms suggestive of SpA between February 2014 and February 2017. Patients with conventional radiographs showing a confirmed sacroiliitis (grade 3 or 4) were not included. Eligible patients underwent CT and MRI of sacroiliac joints (SIJ). CT and MR images were interpreted by 2 experienced musculoskeletal radiologists blinded to clinical and laboratory data. Two professors in rheumatology blinded to radiologists' conclusions analyzed clinical data, laboratory tests, HLA typing, X-rays, CT and MRI images, and divided the patients into 2 groups: confirmed nr-SpA or no SpA. This classification was considered the gold standard when analyzing the results. 46 women and 17 men were included in this study. 47 patients were classified as confirmed nr-SpA (74.6%) and 16 patients as no SpA (25.4%). Sensitivity, specificity, and positive and negative predictive values of CT and MRI for detecting sacroiliitis were, respectively, estimated at 71.7%, 71.4%, 89.2%, 43.5%, and 51.2%, 100%, 100%, and 40%. CT and MRI findings were found to be statistically associated (p<0.001). SIJ MRI is a highly specific method in the detection of sacroiliitis, but with a moderate sensitivity. SIJ CT scan, usually known as the third option after radiography and MRI, has much greater diagnostic utility than it has been documented previously.

The increased anterior talofibular ligament–posterior talofibular ligament angle on MRI may help evaluate chronic ankle instability

PurposeThis study intended to compare the difference between the anterior talofibular ligament (ATFL) and posterior talofibular ligament (PTFL) angle with chronic ankle instability (CAI) patients and healthy volunteers, and to confirm whether using the ATFL–PTFL angle could be a reliable assessment method for CAI, so as to improve the accuracy and specificity of clinical diagnosis.MethodsThis retrospective study included 240 participants: 120 CAI patients and 120 healthy volunteers between 2015 and 2021. The ATFL–PTFL angle of the ankle region was gaged in the cross-sectional supine position on MRI between two groups. After participants undergoing a comprehensive MRI scanning, ATFL–PTFL angles were regarded as the main indicator of patients with the injured ATFLs and healthy volunteers to compare, and were measured by an experienced musculoskeletal radiologist. Moreover, other qualitative and quantitative indicators referring to anatomical and morphological characteristics of the AFTL were included in this study with MRI, such as the length, width, thickness, shape, continuity, and signal intensity of the ATFL, which can be used as secondary indicators.ResultsIn the CAI group, the ATFL–PTFL angle was 90.8° ± 5.7°, which was significantly different from the non-CAI group where the ATFL–PTFL angle for 80.0° ± 3.7° (p < 0.001). As for the ATFL-MRI characteristics, the length (p = 0.003), width (p < 0.001), and thickness (p < 0.001) in the CAI group were also significantly different from the non-CAI group. Over 90% of the cases, patients of the CAI group had injured ATFL with an irregular shape, non-continuous, and high or mixed signal intensity.ConclusionCompared with healthy people, the ATFL–PTFL angle of most CAI patients is larger, which can be used as a secondary index to diagnose CAI. However, the MRI characteristic changes of ATFL may not relate to the increased ATFL–PTFL angle.

Surgical treatment of high-grade acute intramuscular hamstring tendon injuries in athletes leads to predictable return to sports and no re-injuries.

The purpose of this study was to assess the post-operative return to sport and re-injury rates following surgical repair of acute, first-time, high-grade intramuscular hamstring tendon injuries in high level athletes. Patients were identified using the databases of two sports surgeons. Once patients were identified their clinical notes and imaging were reviewed to confirm that all patients had injuries to the intramuscular portion of the distal aspect of the proximal biceps femoris tendon. All imaging was reviewed by an experienced musculoskeletal radiologist to confirm diagnosis. Surgery for such injuries was indicated in high-level athletes presenting with acute hamstring injuries. All patients were operated on within 4weeks. Outcomes included Tegner scores, return to sport, Lower Extremity Functional Score (LEFS), current hamstring symptoms and complications including re-injury. Eleven injuries (10 patients) were included in the study. All patients were male and Australian Rules Football players. Six patients were professional athletes and 4 semi-professional athletes. Median age was 24.5 (range 21-29) and median follow-up period was 33.7months (range; 16-65). 91% were British Athletic Muscle Injury Classification (BAMIC) 3c and 9% were BAMIC 4c. 91% were classed as MR2 and 9% as MR3 on the simplified four-grade injury classification. Athletes achieved return to play (RTP) at an average of 3.1months (SD 1.0) post repair. All but one patient achieved a Tegner score equal to pre-injury levels. Maximum LEFS was achieved by all patients. Minor pain scores (all with VAS < 1/10) on sciatic and functional stretch were recorded in 36% and 27% of patients respectively, with subtle neural symptoms (9%) and subjective tightness (36%) also noted. There were no surgical complications in our patient cohort. No patients had a re-injury or re-operation. Surgical repair of high-grade intramuscular tendon injuries of the biceps femoris hamstring muscle in athletes resulted in high levels of return to pre-injury sporting levels and no re-injuries. The intra-muscular tendon should be scrutinized when assessing hamstring injuries in elite sport and offer surgery in high-grade cases. IV.

MRI radiomics-based machine learning for classification of deep-seated lipoma and atypical lipomatous tumor of the extremities

PurposeTo determine diagnostic performance of MRI radiomics-based machine learning for classification of deep-seated lipoma and atypical lipomatous tumor (ALT) of the extremities.Material and methodsThis retrospective study was performed at three tertiary sarcoma centers and included 150 patients with surgically treated and histology-proven lesions. The training-validation cohort consisted of 114 patients from centers 1 and 2 (n = 64 lipoma, n = 50 ALT). The external test cohort consisted of 36 patients from center 3 (n = 24 lipoma, n = 12 ALT). 3D segmentation was manually performed on T1- and T2-weighted MRI. After extraction and selection of radiomic features, three machine learning classifiers were trained and validated using nested fivefold cross-validation. The best-performing classifier according to previous analysis was evaluated and compared to an experienced musculoskeletal radiologist in the external test cohort.ResultsEight features passed feature selection and were incorporated into the machine learning models. After training and validation (74% ROC-AUC), the best-performing classifier (Random Forest) showed 92% sensitivity and 33% specificity in the external test cohort with no statistical difference compared to the radiologist (p = 0.474).ConclusionMRI radiomics-based machine learning may classify deep-seated lipoma and ALT of the extremities with high sensitivity and negative predictive value, thus potentially serving as a non-invasive screening tool to reduce unnecessary referral to tertiary tumor centers.

Predictive Value of Radiographic and Magnetic Resonance Imaging Characteristics on Patient Outcomes in Confirmed Acute Osteomyelitis of the Extremities.

The aim of this study was to determine whether imaging characteristics on plain radiography, magnetic resonance imaging (MRI), and diffusion-weighted imaging are predictive of patient outcomes in cases of confirmed osteomyelitis (OM). In this cross-sectional study, 3 experienced musculoskeletal radiologists evaluated pathologically proven cases of acute extremity OM and recorded imaging characteristics on plain radiographs, MRI, and diffusion-weighted imaging. These characteristics were then compared with the patient outcomes after a 3-year follow-up using length of stay, amputation-free survival, readmission-free survival, and overall survival using multivariate Cox regression analysis. Hazard ratio and corresponding 95% confidence intervals are reported. False discovery rate-adjusted P values were reported. For the 75 consecutive cases of OM in this study, multivariate Cox regression analysis adjusting for sex, race, age, body mass index, erythrocyte sedimentation rate, C-reactive protein, and white blood cell count showed no correlation among any of the recorded characteristics on imaging and patient outcomes. Despite the high sensitivity and specificity of MRI for diagnosing OM, there was no correlation between MRI characteristics and patient outcomes. Furthermore, patients with coexistent abscess of the soft tissue or bone with OM had comparable outcomes using the previously mentioned metrics of length of stay, amputation-free survival, readmission-free survival, and overall survival. Neither radiography nor MRI features predict patient outcomes in extremity OM.

NKX3.1 immunohistochemistry and methylome profiling in mesenchymal chondrosarcoma: additional diagnostic value for a well-defined disease?

Mesenchymal chondrosarcoma (MCS) is a rare and highly aggressive tumour of soft tissue and bone that is defined by an underlying and highly specific fusion transcript involving HEY1 and NCOA2. Histologically, the tumours show a biphasic appearance consisting of an undifferentiated blue and round cell component as well as islands of highly differentiated cartilage. Particularly in core needle biopsies, the chondromatous component can be missed and the non-specific morphology and immunophenotype of the round cell component can cause diagnostic challenges. We applied NKX3.1 immunohistochemistry which was recently reported as a highly specific marker as well as methylome and copy number profiling to a set of 45 well characterised MCS cases to evaluate their potential diagnostic value. Methylome profiling revealed a highly distinct cluster for MCS. Notably, the findings were reproducible also when analysing the round cell and cartilaginous component separately. Furthermore, four outliers were identified by methylome profiling for which the diagnosis had to be revised. NKX3.1 immunohistochemistry showed positivity in 36% of tumours, the majority of which was rather focal and weak. Taken together, NKX3.1 expression showed a low sensitivity but a high specificity in our analysis. Methylome profiling on the other hand represents a sensitive, specific and reliable tool to support the diagnosis of MCS, particularly if only the round cell component is obtained in a biopsy and the diagnosis is not suspected. Furthermore, it can aid in confirming the diagnosis in case RNA sequencing for the HEY1::NCOA2 fusion transcript is not available.

Reliability and Validity of Single Axial Slice vs. Multiple Slice Quantitative Measurement of the Volume of Effusion-Synovitis on 3T Knee MRI in Knees with Osteoarthritis.

Effusion-synovitis (ES) is recognized as a component of osteoarthritis, creating a need for rapid methods to assess ES on MRI. We describe the development and reliability of an efficient single-slice semi-automated quantitative approach to measure ES. We used two samples from the Osteoarthritis Initiative (OAI): 50 randomly selected OAI participants with radiographic osteoarthritis (i.e., Kellgren-Lawrence (KL) grade 2 or 3) and a subset from the Foundation for the National Institutes of Health Osteoarthritis Biomarker study. An experienced musculoskeletal radiologist trained four non-expert readers to use custom semi-automated software to measure ES on a single axial slice and then read scans blinded to prior assessments. The estimated intraclass correlation coefficient (ICC) for intra-reader reliability of the single-slice ES method in the KL 2-3 sample was 0.96 (95% CI: 0.93, 0.97), and for inter-reader reliability, the ICC was 0.90 (95% CI: 0.87, 0.95). The intra-reader mean absolute difference (MAD) was 35 mm3 (95% CI: 28, 44), and the inter-reader MAD was 61 mm3 (95% CI: 48, 76). Our single-slice quantitative knee ES measurement offers a reliable, valid, and efficient surrogate for multi-slice quantitative and semi-quantitative assessment.

The use of radiomics and machine learning for the differentiation of chondrosarcoma from enchondroma.

To construct and compare machine learning models for differentiating chondrosarcoma from enchondroma using radiomic features from T1 and fat suppressed Proton density (PD) magnetic resonance imaging (MRI). Eighty-eight patients (57 with enchondroma, 31 with chondrosarcoma) were retrospectively included. Histogram matching and N4ITK MRI bias correction filters were applied. An experienced musculoskeletal radiologist and a senior resident in radiology performed manual segmentation. Voxel sizes were resampled. Laplacian of Gaussian filter and wavelet-based features were used. One thousand eight hundred eighty-eight features were obtained for each patient, with 944 from T1 and 944 from PD images. Sixty-four unstable features were removed. Seven machine learning models were used for classification. Classification with all features showed neural network was the best model for both readers' datasets with area under the curve (AUC), classification accuracy (CA), and F1 score of 0.979, 0.984; 0.920, 0.932; and 0.889, 0.903, respectively. Four features, including one common to both readers, were selected using fast correlation based filter. The best performing models with selected features were gradient boosting for Fatih Erdem's dataset and neural network for Gülen Demirpolat's dataset with AUC, CA, and F1 score of 0.990, 0.979; 0.943, 0.955; 0.921, 0.933, respectively. Neural Network was the second-best model for FE's dataset based on AUC (0.984). Using pathology as a gold standard, this study defined and compared seven well-performing models to distinguish enchondromas from chondrosarcomas and provided radiomic feature stability and reproducibility among the readers.

Incremental value of diffusion weighted imaging over conventional MRI for the diagnosis of osteomyelitis of extremities.

To determine the incremental value of diffusion weighted imaging (DWI) over conventional MR imaging in diagnosing extremity osteomyelitis (OM). In this cross-sectional study, three experienced musculoskeletal radiologists evaluated clinically suspected cases of extremity OM in two rounds-first on conventional MR imaging, and then conventional MR imaging combined with DWI 4-6 weeks later. The readers recorded a result of the presence or absence of OM and their diagnostic confidence on a 1-5 scale. Mean and minimum apparent diffusion coefficient (ADC) were measured. Pathology diagnosis served as the reference standard. Statistical analysis utilized intraclass correlation (ICC) and Conger's kappa. A total of 213 scans of suspected OM were reviewed by three musculoskeletal radiologists with no significant changes in sensitivity (0.97, 0.97), specificity (0.97, 0.94), positive predictive value (0.91, 0.87), or negative predictive value (0.98, 0.98) between conventional MR imaging and MR imaging combined with DWI, respectively. Reader confidence did not significantly change with the addition of DWI (4.55 and 4.70, respectively). A high inter-reader agreement was observed for the diagnosis of OM, soft tissue abscess, and intraosseous abscess in both rounds. A higher mean (1.46+/-0.43 × 10-3 mm2/s > 0.64+/-0.47 × 10-3mm2/s) and minimum (1.18+/-0.45 × 10-3mm2/s > 0.37+/-0.44 × 10-3mm2/s) ADC value was associated with OM (p-value < 0.0001) with odds ratios of 1.34 and 1.31, respectively, for mean and minimum ADC of the involved bone. DWI-derived ADC increase is associated with OM. The use of DWI slightly increases reader confidence in the diagnosis of OM; however, no significant incremental value over conventional MR imaging is seen for the final diagnosis of OM.

Diagnostic Accuracy of 128-Slice Single-Source CT for the Detection of Dislocated Bucket Handle Meniscal Tears in the Setting of an Acute Knee Trauma—Correlation with MRI and Arthroscopy

(1) Background: Meniscal tears are amongst the most common knee injuries. Dislocated bucket handle meniscal tears in particular should receive early intervention. The purpose of this study was to evaluate the diagnostic performance of CT in detecting dislocated bucket handle meniscal tears compared with the gold-standard MRI and arthroscopy. (2) Methods: Retrospectively, 96 consecutive patients underwent clinically indicated CT of the knee for suspected acute traumatic knee injuries (standard study protocol, 120 kV, 90 mAs). Inclusion criteria were the absence of an acute fracture on CT and a timely MRI (<6 months). Corresponding arthroscopy was assessed. Two experienced musculoskeletal radiologists analyzed the images for dislocated bucket handle meniscal tears, associated signs thereof (double posterior cruciate ligament sign, double delta sign, disproportional posterior horn sign), and subjective diagnostic confidence on a 5-point-Likert scale (1 = 'non-diagnostic image quality', 5 = 'very confident'). (3) Results: Dislocated bucket handle meniscal tears were detected on CT by standard three-plane bone kernel reconstructions with a sensitivity of 90.7% and a specificity of 99.3% by transferring the knowledge of established MRI signs. The additional use of soft-tissue kernel reconstructions in three planes increased the sensitivity by 4.0% to 94.7%, specificity to 100%, inter-rater agreement to 1.0, and the diagnostic confidence of both readers improved to a median 4/5 ('confident') in both readers. (4) Conclusions: Trauma CT scan of the knee with three-plane soft-tissue reconstructions delivers the potential for the detection of dislocated bucket handle meniscal tears with very high diagnostic accuracy.

Tumor-to-bone distance and radiomic features on MRI distinguish intramuscular lipomas from well-differentiated liposarcomas

BackgroundTo develop a machine learning model based on tumor-to-bone distance and radiomic features derived from preoperative MRI images to distinguish intramuscular (IM) lipomas and atypical lipomatous tumors/well-differentiated liposarcomas (ALTs/WDLSs) and compared with radiologists.MethodsThe study included patients with IM lipomas and ALTs/WDLSs diagnosed between 2010 and 2022, and with MRI scans (sequence/field strength: T1-weighted (T1W) imaging at 1.5 or 3.0 Tesla MRI). Manual segmentation of tumors based on the three-dimensional T1W images was performed by two observers to appraise the intra- and interobserver variability. After radiomic features and tumor-to-bone distance were extracted, it was used to train a machine learning model to distinguish IM lipomas and ALTs/WDLSs. Both feature selection and classification steps were performed using Least Absolute Shrinkage and Selection Operator logistic regression. The performance of the classification model was assessed using a tenfold cross-validation strategy and subsequently evaluated using the receiver operating characteristic curve (ROC) analysis. The classification agreement of two experienced musculoskeletal (MSK) radiologists was assessed using the kappa statistics. The diagnosis accuracy of each radiologist was evaluated using the final pathological results as the gold standard. Additionally, we compared the performance of the model and two radiologists in terms of the area under the receiver operator characteristic curves (AUCs) using the Delong’s test.ResultsThere were 68 tumors (38 IM lipomas and 30 ALTs/WDLSs). The AUC of the machine learning model was 0.88 [95% CI 0.72–1] (sensitivity, 91.6%; specificity, 85.7%; and accuracy, 89.0%). For Radiologist 1, the AUC was 0.94 [95% CI 0.87–1] (sensitivity, 97.4%; specificity, 90.9%; and accuracy, 95.0%), and as to Radiologist 2, the AUC was 0.91 [95% CI 0.83–0.99] (sensitivity, 100%; specificity, 81.8%; and accuracy, 93.3%). The classification agreement of the radiologists was 0.89 of kappa value (95% CI 0.76–1). Although the AUC of the model was lower than of two experienced MSK radiologists, there was no statistically significant difference between the model and two radiologists (all P > 0.05).ConclusionsThe novel machine learning model based on tumor-to-bone distance and radiomic features is a noninvasive procedure that has the potential for distinguishing IM lipomas from ALTs/WDLSs. The predictive features that suggested malignancy were size, shape, depth, texture, histogram, and tumor-to-bone distance.

Dynamic ultrasound assessment of hip instability and anterior and posterior hip impingement.

In this technical report, we describe our protocol for the dynamic sonographic evaluation of the hip and assess reliability of the ultrasound assessment of hip microinstability. Our clinical experience with a standardized dynamic ultrasound of the hip performed in a series of 27 patients with imaging performed by an experienced musculoskeletal radiologist during physical examination by an orthopedic surgeon specializing in hip preservation is illustrated with clinical photographs and ultrasound images from volunteers and selected patients. Interrater reliability for the diagnosis of microinstability was calculated. Dynamic ultrasound technique and findings of hip instability, femoroacetabular impingement, and ischiofemoral impingement with corresponding clinical photos showing the necessary physical examination maneuvers are described. Interrater agreement for the diagnosis of microinstability was substantial (κ 0.606 [0.221-0.991]). At our institution, dynamic ultrasound of the hip during physical examination complements information gathered from static imaging by providing real-time correlation of symptoms with what is occurring anatomically.

Poster 200: High Prevalence of Abnormal Imaging Findings in Clinically Asymptomatic Siblings Of JOCD Patients On 3T Knee MRI

Objectives:Endochondral ossification is a skeletal developmental process in children by which the embryonic cartilaginous model of bones undergoes gradual ossification over time until skeletal maturity is reached. Juvenile Osteochondritis Dissecans (JOCD) is a developmental disease characterized by focal areas of chondronecrosis within the epiphyseal cartilage and subsequent delay of the ossification front. JOCD lesions can become loose bodies and lead to premature Osteoarthritis. The etiology of JOCD is not yet well understood, however, there is mounting evidence of a genetic predisposition. Recently, positive familial history, including familial OCD and a genome-wide association study in humans identified genetic loci related to juvenile OCD. In this longitudinal pilot study, we examined siblings of JOCD patients utilizing clinical 3T MRI data to evaluate morphological integrity of the epiphyseal cartilage and the advancing ossification front in the distal femoral condyles in bilateral knees. We hypothesized that asymptomatic, clinically “silent” JOCD lesions could be detected in young siblings of patients affected by JOCD.Methods:In this longitudinal study, 44 MRI datasets from seven skeletally immature participants with no clinical symptoms (7 siblings of JOCD patients; 3 females; 12 bilateral knees; average age at first visit=8.7 years; range=6-10 years) were evaluated. This study was approved by the institutional review board and informed consent was obtained. All images were acquired at 3T MRI system with a 1Tx/15Rx knee coil. Sagittal PD-weighted TSE images without fat suppression (TR/TE = 3900/40 ms, resolution = 0.36x0.36 mm2, scanning time = 1min:49s) and with fat suppression (TR/TE = 3530/40 ms, resolution = 0.36x0.36 mm2, scanning time = 3min:46s) were acquired bilaterally at first visit and at multiple MRI follow-up studies ranging from 6-21 months. The images were reviewed by an experienced musculoskeletal radiologist using the following MRI criteria: (i) integrity of the ossification front; (ii) presence/absence of bone marrow edema; (iii) intact/disrupted secondary physis; and (iv) T2 hyperintensity in epiphyseal cartilage.Results:Five of seven participants (71%) met at least one of the MRI criteria defining a JOCD lesion. Six of the seven participants (86%) had an irregular ossification front at the distal aspect of the medial and/or lateral femoral epicondyles, focal areas of T2 hyperintensities in the epiphyseal cartilage, and a disrupted secondary physis. Of the 13 imaged knees, two knees (both lateral and medial epicondyle) from the same participant and two knees (only lateral epicondyle) had no abnormal MRI findings (= 6 normal epicondyles). Abnormal findings in the medial and lateral epicondyles of the remaining bilateral knees resolved over time in 11 epicondyles (Fig. 1), whereas in the remaining 9 epicondyles the abnormal findings persisted or progressed (Fig. 2).Conclusions:The most important finding of this pilot study is the high prevalence (6 out of 7, 86%) of morphological changes during skeletal development in this group of first-degree relatives of JOCD patients. Furthermore, 71% (5 out of 6) of participants met the imaging criteria for early JOCD lesions at least at one time point during the study without developing any clinical symptoms. There is mounting evidence of a genetic contribution to the etiology of JOCD. In the literature, so called ossification variants are considered morphological variants of bone shape with an overall prevalence of 12% and are believed to resolve naturally over time. While 55% of the epicondyles with abnormalities in the ossification front in our cohort resolved over time on MRI, during the course of this study – typically 8-21 months, the remaining 45% did not resolve or occurred at the last imaging time point with associated marrow edema and needed clinical surveillance. A high incidence of MRI abnormalities in the ossification front, epiphyseal cartilage and secondary physis in a clinically asymptomatic study group of first degree relatives of patients with JOCD supports the hypothesis a) that there is a strong genetic predisposition for this disease, b) clinically “silent” initial stages of the disease could be overlooked, challenging the common current understanding of normal physiologic “ossification variants”.Figure 1.Sagittal PD-weighted TSE w/o fat-suppression (FS) of the lateral femoral condyle in a 10-year-old boy. The follow-up studies demonstrate complete resolution of the irregular ossification front (arrowhead), absence of bone marrow edema.Figure 2.Sagittal PD-weighted TSE w/o fat-suppression (FS) of the lateral femoral condyle in a 10-year-old boy. The baseline study demonstrates a focal T2-hyperintense lesion (arrow) and a delayed ossification front with associated bone marrow edema (*) meeting the MR imaging criteria for an early JOCD lesion. The asymptomatic sibling was clinically surveilled and subsequent follow-up studies demonstrated resolution of the MR imaging findings.

Can indirect magnetic resonance arthrography be a good alternative to magnetic resonance imaging in diagnosing glenoid labrum lesions?: a prospective study.

BackgroundThis study was designed to evaluate and compare the diagnostic value of magnetic resonance imaging (MRI) and indirect magnetic resonance arthrography (I-MRA) imaging with those of arthroscopy and each other.MethodsThis descriptive-analytical study was conducted in 2020. All patients who tested positive for labrum lesions during that year were included in the study. The patients underwent conservative treatment for 6 weeks. In the event of no response to conservative treatment, MRI and I-MRA imaging were conducted, and the patients underwent arthroscopy to determine their ultimate diagnosis and treatment plan. Imaging results were assessed at a 1-week interval by an experienced musculoskeletal radiologist. Image interpretation results and arthroscopy were recorded in the data collection form.ResultsOverall, 35 patients comprised the study. Based on the kappa coefficient, the results indicate that the results of both imaging methods are in agreement with the arthroscopic findings, but the I-MRA consensus rate is higher than that of MRI (0.612±0.157 and 0.749±0.101 vs. 0.449±0.160 and 0.603±0.113). The sensitivity, specificity, negative predictive value, positive predictive value, and accuracy of MRI in detecting labrum tears were77.77%, 75.00%, 91.30%, 50.00%, and 77.14%, respectively, and those of I-MRA were 88.88%, 75.00%, 92.30%, 66.66%, and 85.71%.ConclusionsHere, I-MRA showed higher diagnostic value than MRI for labral tears. Therefore, it is recommended that I-MRA be used instead of MRI if there is an indication for potential labrum lesions.