Opportunistic Screening for Acute Vertebral Fractures on a Routine Abdominal or Chest Computed Tomography Scans Using an Automated Deep Learning Model.

OBJECTIVES: To develop an opportunistic screening model based on a deep learning algorithm to detect recent vertebral fractures in abdominal or chest CTs. MATERIALS AND METHODS: A total of 1309 coronal reformatted images (504 with a recent fracture from 119 patients, and 805 without fracture from 115 patients), from torso CTs, performed from September 2018 to April 2022, on patients who also had a spine MRI within two months, were included. Two readers participated in image selection and manually labeled the fractured segment on each selected image with Neuro-T (version 2.3.3; Neurocle Inc.) software. We split the images randomly into the training and internal test set (labeled: unlabeled = 480:700) and the secondary interval validation set (24:105). For the observer study, three radiologists reviewed the CT images in the external test set with and without deep learning assistance and scored the likelihood of an acute fracture in each image independently. RESULTS: For the training and internal test sets, the AI achieved a 99.86% test accuracy, 91.22% precision, and 89.18% F1 score for detection of recent fracture. Then, in the secondary internal validation set, it achieved 99.90%, 74.93%, and 78.30%, respectively. In the observer study, with the assistance of the deep learning algorithm, a significant improvement was observed in the radiology resident's accuracy, from 92.79% to 98.2% (p = 0.04). CONCLUSION: The model showed a high level of accuracy in the test set and also the internal validation set. If this algorithm is applied opportunistically to daily torso CT evaluation, it will be helpful for the early detection of fractures that require treatment.

Deep Learning-Assisted Quantitative Measurement of Thoracolumbar Fracture Features on Lateral Radiographs.

OBJECTIVE: This study aimed to develop and validate a deep learning (DL) algorithm for the quantitative measurement of thoracolumbar (TL) fracture features, and to evaluate its efficacy across varying levels of clinical expertise. METHODS: Using the pretrained Mask Region-Based Convolutional Neural Networks model, originally developed for vertebral body segmentation and fracture detection, we fine-tuned the model and added a new module for measuring fracture metrics-compression rate (CR), Cobb angle (CA), Gardner angle (GA), and sagittal index (SI)-from lumbar spine lateral radiographs. These metrics were derived from six-point labeling by 3 radiologists, forming the ground truth (GT). Training utilized 1,000 nonfractured and 318 fractured radiographs, while validations employed 213 internal and 200 external fractured radiographs. The accuracy of the DL algorithm in quantifying fracture features was evaluated against GT using the intraclass correlation coefficient. Additionally, 4 readers with varying expertise levels, including trainees and an attending spine surgeon, performed measurements with and without DL assistance, and their results were compared to GT and the DL model. RESULTS: The DL algorithm demonstrated good to excellent agreement with GT for CR, CA, GA, and SI in both internal (0.860, 0.944, 0.932, and 0.779, respectively) and external (0.836, 0.940, 0.916, and 0.815, respectively) validations. DL-assisted measurements significantly improved most measurement values, particularly for trainees. CONCLUSION: The DL algorithm was validated as an accurate tool for quantifying TL fracture features using radiographs. DL-assisted measurement is expected to expedite the diagnostic process and enhance reliability, particularly benefiting less experienced clinicians.

Histiocytic sarcoma mimicking localized tenosynovial giant cell tumor in the pediatric foot: A rare case report with MRI Findings.

We present a rare case of histiocytic sarcoma (HS) occurring in the foot of a 12-year-old male, initially misdiagnosed as localized tenosynovial giant cell tumor (TSGCT). HS is an exceptionally uncommon hematologic malignant neoplasm, with its occurrence in children and extranodal sites being even rarer. To our knowledge, this is the first reported case of extranodal HS in the foot, emphasizing comprehensive MRI findings. Initially, the patient was diagnosed with TSGCT based on histological results following surgical resection. However, after recurrence and subsequent surgical resection, histological and immunochemical analyses led to a revised diagnosis of HS. This report focuses on the MRI findings of HS, highlighting the distinctions from localized TSGCT. While both conditions share histopathological similarities, immunohistochemical tests are crucial for accurate diagnosis. The report underscores the importance of differentiating HS for appropriate treatment.

Deep learning system for automated detection of posterior ligamentous complex injury in patients with thoracolumbar fracture on MRI.

This study aimed to develop a deep learning (DL) algorithm for automated detection and localization of posterior ligamentous complex (PLC) injury in patients with acute thoracolumbar (TL) fracture on magnetic resonance imaging (MRI) and evaluate its diagnostic performance. In this retrospective multicenter study, using midline sagittal T2-weighted image with fracture (± PLC injury), a training dataset and internal and external validation sets of 300, 100, and 100 patients, were constructed with equal numbers of injured and normal PLCs. The DL algorithm was developed through two steps (Attention U-net and Inception-ResNet-V2). We evaluate the diagnostic performance for PLC injury between the DL algorithm and radiologists with different levels of experience. The area under the curves (AUCs) generated by the DL algorithm were 0.928, 0.916 for internal and external validations, and by two radiologists for observer performance test were 0.930, 0.830, respectively. Although no significant difference was found in diagnosing PLC injury between the DL algorithm and radiologists, the DL algorithm exhibited a trend of higher AUC than the radiology trainee. Notably, the radiology trainee's diagnostic performance significantly improved with DL algorithm assistance. Therefore, the DL algorithm exhibited high diagnostic performance in detecting PLC injuries in acute TL fractures.

Predictors of Extraprostatic Extension in Patients with Prostate Cancer.

PURPOSE: To identify effective factors predicting extraprostatic extension (EPE) in patients with prostate cancer (PCa). METHODS: This retrospective cohort study recruited 898 consecutive patients with PCa treated with robot-assisted laparoscopic radical prostatectomy. The patients were divided into EPE and non-EPE groups based on the analysis of whole-mount histopathologic sections. Histopathological analysis (ISUP biopsy grade group) and magnetic resonance imaging (MRI) (PI-RADS v2.1 scores [1-5] and the Mehralivand EPE grade [0-3]) were used to assess the prediction of EPE. We also assessed the clinical usefulness of the prediction model based on decision-curve analysis. RESULTS: Of 800 included patients, 235 (29.3%) had EPE, and 565 patients (70.7%) did not (non-EPE). Multivariable logistic regression analysis showed that the biopsy ISUP grade, PI-RADS v2.1 score, and Mehralivand EPE grade were independent risk factors for EPE. In the regression assessment of the models, the best discrimination (area under the curve of 0.879) was obtained using the basic model (age, serum PSA, prostate volume at MRI, positive biopsy core, clinical T stage, and D'Amico risk group) and Mehralivand EPE grade 3. Decision-curve analysis showed that combining Mehralivand EPE grade 3 with the basic model resulted in superior net benefits for predicting EPE. CONCLUSION: Mehralivand EPE grades and PI-RADS v2.1 scores, in addition to basic clinical and demographic information, are potentially useful for predicting EPE in patients with PCa.

Fibrosarcoma of Great Toe Shown with Multimodality Radiologic Imaging Features.

INTRODUCTION: Fibrosarcoma of bone is a rare malignant spindle cell tumor. CASE STUDY: Herein, we present a case of fibrosarcoma in a 40-year-old male who was presented to the clinic with left-sided great toe pain for 20 years. Simple radiographs showed acrolysis at the distal phalanx of great toe. Magnetic resonance imaging (MRI) revealed a 1.5 cm sized heterogenous high signal intensity mass on T2-weighted images and iso signal intensity on T1- weighted images. Dorsal and distal portion of the mass showed markedly dark signal intensity on T1 and T2-weighted images. CONCLUSION: In an enhanced image, the mass showed heterogenous enhancement. Surgical removal was performed and pathologic analysis revealed fibrosarcoma. Although extremely rare, fibrosarcoma of the bone should be kept in mind as a possibility when a lesion exhibits a black signal intensity component on an MRI with acrolysis.

MRI Findings of Periarticular Lesions with Isolated Greater Tubercle Fractures and Dislocation.

PURPOSE: To identify MRI findings for injuries to periarticular soft tissue structures that were related to isolated greater tubercle fracture. MATERIALS AND METHODS: 16 patients (mean age: 53.8, range 30-71 yrs) were enrolled and diagnosed with isolated greater tubercle (GT) fracture with CT and MRI and underwent shoulder arthroscopy from September 2009 to April 2019. Two musculoskeletal radiologists were blinded to the patient history and arthroscopic surgical findings and reviewed patient's CT and MRI. Fracture displacement, fracture center, and presence of bony Bankart lesion with Hill sachs lesion were checked on shoulder CT. Soft tissue injuries, including rotator cuff injury, deltoid muscle injury, long head of biceps tendon injury, capsular injury, glenoid injury, and injury location of the subscapularis and infraspinatus were checked on shoulder MRI. RESULTS: MRI showed supraspinatus injury (56.3%), subscapularis injury (56.3%), deltoid muscle injury (25%), infraspinatus injury (25%), teres minor muscle injury (37.5%), injury of the long head of the biceps tendon (43.8%), inferior glenohumeral ligament tear (87.5%), superior labral anterior-toposterior lesion (25%), Bankart lesion (18.8%), and Hill-Sachs lesion (6.3%). 88.9% of subscapularis injuries and 75% of infraspinatus injuries showed caudal predominance. All of the patients with infraspinatus injuries showed concomitant teres minor muscle injuries. In order of frequency, the fracture centers were anterior (25%), posterior (31.3%), and all (43.8%). For patients with Bankart and Hill- Sachs lesions, the fracture center included the posterior portion in all cases. CONCLUSION: MRI and active arthroscopic examinations may be valuable when an isolated GT avulsion fracture is identified on X-ray examination.

Prediction of anterior tibiotalar ligament injury: measurement of the angle between the deep posterior tibiotalar ligament and talus on MRI.

BACKGROUND: Identification of anterior tibiotalar ligament (aTTL) injury is essential because it influences the surgeon's treatment option and patient prognosis. PURPOSE: To assess the diagnostic accuracy of the angle measurement between the talus and posterior tibiotalar ligament (talus-pTTL) on magnetic resonance imaging (MRI) in patients with arthroscopically proven aTTL injuries. MATERIAL AND METHODS: Ankle MRI scans of 67 patients who underwent arthroscopic examination were retrospectively reviewed. The talus-pTTL angle on axial T2-weighted MRI and the medial clear space (MCS) on mortise ankle radiograph were measured. Inter-observer agreement of the measurements was calculated. Also, sensitivity, specificity, and area under the receiver operating characteristic (ROC) curve (AUC) were the metrics of diagnostic accuracy. RESULTS: AUC was 0.90 for observer 1 with 78.6% sensitivity, 97.4% specificity, 88% accuracy, and 54.7° cutoff value for the talus-pTTL angle. AUC was 0.87 for observer 2 with 85.7% sensitivity, 84.6% specificity, 85.2% accuracy, and 53.7° cutoff value for the talus-pTTL angle. AUC was 0.86 with 82.1% sensitivity, 79.5% specificity, and 80.8% accuracy for observer 1 and 0.79 with 57.1% sensitivity, 92.3% specificity, and 74.7% accuracy for observer 2 for the MCS. Different MCS values and additional capabilities when complemented with the angle measurement showed an increase in diagnostic performances. Intra-observer reliability of MCS and talus-pTTL angle of the two radiologists was excellent. Inter-observer reliability of the two radiologists was excellent for both the talus-pTTL angle (0.95) and the MCS (0.85). CONCLUSION: Measurement of the talus-pTTL angle showed good sensitivity, specificity, and accuracy for the evaluation of aTTL injury with excellent inter-observer reliability.

Extradural Spinal Lymphoplasmacyte-Rich Meningioma in the Thoracic Spine: A Case Report and Literature Review.

Most spinal meningiomas have an intradural or partly extradural location. The meningothelial origin is the most common pathologic type of spinal meningioma. Pure extradural spinal meningiomas are not common, and lymphoplasmacyte-rich meningioma (LPRM) is very rare. We report a case of isolated extradural spinal meningioma in the thoracic spine that was pathologically confirmed as LPRM.

Extra-Abdominal Desmoid-Type Fibromatosis Mimicking Myxofibrosarcoma.

A 27-year-old woman was confirmed to have extraabdominal desmoid-type fibromatosis. Desmoid-type fibromatosis is a very rare connective tissue neoplasm with the extraabdominal type even more rare. It is most commonly found in proximal structures such as shoulders, neck, chest, and extremities. There are few case reports for desmoid-type fibromatosis located in paraspinal soft tissue. We report a case of desmoid-type fibromatosis mimicking a myxofibrosarcoma. Teaching Point: Even if there are suggestive findings for malignant soft tissue tumor on radiologic evaluation, histological confirmation is necessary before surgical treatment.

Intraosseous ganglion cyst mimicking chondrosarcoma on MRI: a case report.

BACKGROUND: The intraosseous ganglia is a benign cyst, rarely locate in the olecranon process. As intraosseous ganglia can mimic malignant bone tumor, computed tomography (CT) is important for diagnosis even when magnetic resonance imaging (MRI) suggests malignant bone tumor, such as chondrosarcoma. CASE PRESENTATION: In this paper, we report a 42-year-old woman with intraosseous ganglia in the olecranon process of the ulna. She complained pain in right elbow for 3 weeks. MRI revealed an intraosseous mass which initially diagnosed as chondrosarcoma. However, followed computed tomography (CT) demonstrated scattered intralesional gas and no underlying mineralization, and we can exclude chondrosarcoma from diagnosis. CONCLUSIONS: The intraosseous ganglia can mimic bone tumor in MRI; therefore, CT is essential for accurate characterization of bone tumor. Even if MR imaging strongly suggests chondrosarcoma of the bone, CT should be performed as additional study.

Early Imaging Findings of Hypertrophic Osteoarthropathy Mimicking Bone Metastasis from Extrathoracic Malignancy.

Hypertrophic osteoarthropathy (HOA) is a syndrome characterized by digital clubbing, periosteal bone formation, and synovial effusions. Secondary HOA is associated with intrathoracic malignancy in most cases; however, in rare cases, HOA can be caused by extrathoracic conditions. We report early ultrasound, computed tomography, magnetic resonance imaging, and bone scintigraphy findings of HOA in a patient with breast cancer. Its ambiguous clinical and imaging findings that mimicked malignant conditions are particularly interesting and informative.

Ultrasonography-guided intra-articular steroid injection in the hip for symptomatic round ligament partial tear or degeneration.

PURPOSE: The objectives of this study were to demonstrate the benefits of ultrasonography-guided intra-articular steroid injection in the hip (UISIH) for the treatment of partial tear or degeneration of the round ligament of the femur and to determine the prognostic factors for this treatment. METHODS: We retrospectively analyzed the records of 40 patients who were diagnosed with a partial tear or degeneration of the round ligament of the femur and who underwent UISIH between August 2014 and November 2018. The inclusion criteria were a lack of history of UISIH or other interventional procedure and the presence of follow-up records after the hip injection. The short-term clinical outcome was evaluated at the first follow-up appointment after UISIH. Possible prognostic factors for UISIH such as age, sex, injection side, and average follow-up time were analyzed using the chi-square test, the Fisher exact test, and the t test. RESULTS: UISIH was found to have been effective in 35 of the 40 patients (87.5%) at the first follow-up visit. The average follow-up time was 43 days. No significant differences were observed in the clinical outcome of UISIH with respect to age, sex, injection side, or follow-up time. CONCLUSION: In this study, we demonstrated that UISIH was a safe and effective treatment in patients with a partial tear or degeneration of the round ligament of the femur over the course of short-term follow-up. Age, sex, injection side, and follow-up time were not identified as prognostic factors for this treatment.

Primary neuroendocrine carcinoma of the breast: radiologic and pathologic correlation.

Primary neuroendocrine carcinoma of the breast (PNCB) is a rare type of breast cancer. There have been few reports on PNCB and radiologic-pathologic correlation in PNCB has not been described thoroughly. We present a rare case of pathologically confirmed poorly differentiated PNCB removed via lumpectomy. Image findings on mammography, ultrasonography, computed tomography, magnetic resonance image, and positron emission tomography-computed tomography are also presented.