PURPOSE:Abnormal restrictions at myofascial interfaces are a key factor in chronic low back pain (CLBP) with myofascial pain syndrome (MPS), but no established imaging method exists for quantitative assessment. This pilot study evaluated the clinical feasibility of MR elastography (MRE)-based slip interface imaging (SII) for visualizing myofascial mobility in CLBP-MPS patients versus age-/sex-/BMI-matched healthy participants. A new SII biomarker, maximal normalized displacement discontinuity ( D norm $$ {D}_{norm} $$ ), was introduced, and the previously developed normalized octahedral shear strain (NOSS) map was used for comparison. Preliminary assessments of vibration-frequency effects, repeatability, and group differences in inter-muscular mobility were conducted. METHODS:MRE was conducted at 30, 60, and 90 Hz to compare D norm $$ {D}_{norm} $$ with NOSS for visualizing inter-muscular slip interfaces at the quadratus lumborum-erector spinae (QL-ES) and erector spinae-multifidus (ES-M) muscle boundaries at L3-L4. Repeatability of D norm $$ {D}_{norm} $$ and NOSS was assessed at 30 Hz (identified as the best-performing frequency) using within-subject coefficients of variation and a linear mixed-effects model from within- and between-day scans. Clinical feasibility was then assessed via Wilcoxon rank-sum tests in six CLBP-MPS patients and matched controls. RESULTS:D norm $$ {D}_{norm} $$ at 30 Hz exhibited superior delineation of slip interfaces compared to higher frequencies and NOSS. D norm $$ {D}_{norm} $$ demonstrated significantly lower variation and better repeatability than NOSS. Healthy participants showed continuous, well-defined slip interfaces, whereas CLBP-MPS patients displayed disrupted interfaces with significant mobility reduction at L4 ES-M. CONCLUSION:SII with lower vibration frequency and D norm $$ {D}_{norm} $$ map enhances visualization of lower back myofascial mobility and shows potential for assessing differences between healthy individuals and CLBP-MPS patients.

Tumor thrombus arising from osteosarcoma is rare, with only a few cases documented in the literature. Herein, we report a case of locally recurrent osteosarcoma complicated by tumor thrombus in a patient who had undergone prior neoadjuvant chemotherapy, surgical resection, and rotationplasty for a distal left femoral osteosarcoma. An [18F] FDG PET/CT scan revealed an FDG-avid locally recurrent tumor in the soft tissues of the left thigh contiguous with FDG-avid tumor thrombus extending from the mid-left femoral vein to the left external iliac vein. This case illustrates that, although rare, osteosarcoma can cause tumor thrombus, and [18F] FDG PET/CT can be a useful diagnostic tool in such cases.

BackgroundDual-energy CT (DECT) is a non-invasive way to determine the presence of monosodium urate (MSU) crystals in the workup of gout. Color-coding distinguishes MSU from calcium following material decomposition and post-processing. Most software labels MSU as green and calcium as blue. There are limitations in the current image processing methods of segmenting green-encoded pixels. Additionally, identifying green foci is tedious, and automated detection would improve workflow. This study aimed to determine the optimal deep learning (DL) algorithm for segmenting green-encoded pixels of MSU crystals on DECTs.MethodsDECT images of positive and negative gout cases were retrospectively collected. The dataset was split into train (N = 28) and held-out test (N = 30) sets. To perform cross-validation, the train set was split into seven folds. The images were presented to two musculoskeletal radiologists, who independently identified green-encoded voxels. Two 3D Unet-based DL models, Segresnet and SwinUNETR, were trained, and the Dice similarity coefficient (DSC), sensitivity, and specificity were reported as the segmentation metrics.ResultsSegresnet showed superior performance, achieving a DSC of 0.9999 for the background pixels, 0.7868 for the green pixels, and an average DSC of 0.8934 for both types of pixels, respectively. According to the post-processed results, the Segresnet reached voxel-level sensitivity and specificity of 98.72 % and 99.98 %, respectively.ConclusionIn this study, we compared two DL-based segmentation approaches for detecting MSU deposits in a DECT dataset. The Segresnet resulted in superior performance metrics. The developed algorithm provides a potential fast, consistent, highly sensitive and specific computer-aided diagnosis tool. Ultimately, such an algorithm could be used by radiologists to streamline DECT workflow and improve accuracy in the detection of gout.

Posterior shoulder instability is an uncommon but important cause of shoulder dysfunction and pain which may occur as the result of seizure, high energy trauma, or repetitive stress related to occupational or sport-specific activities. This current review details the imaging approach to the patient with posterior shoulder instability and describes commonly associated soft tissue and bony pathologies identified by radiographs, CT, and MR imaging. Advances in MR imaging technology and techniques allow for more accurate evaluation of bone and soft tissue pathology associated with posterior shoulder instability while sparing patients exposure to radiation. Imaging can contribute significantly to the clinical management of patients with posterior shoulder instability by demonstrating the extent of associated injuries and identifying predisposing anatomic conditions. Radiologic evaluation should be guided by clinical history and physical examination, beginning with radiographs followed by CT and/or MRI for assessment of osseous and soft tissue pathology. Synthesis of a patient’s clinical history, physical exam findings, and radiologic examinations should guide clinical management.

IntroductionDual-energy CT (DECT) is a non-invasive way to determine the presence of monosodium urate (MSU) crystals in the workup of gout. Color-coding distinguishes MSU from calcium following material decomposition and post-processing. Manually identifying these foci (most commonly labeled green) is tedious, and an automated detection system could streamline the process. This study aims to evaluate the impact of a deep-learning (DL) algorithm developed for detecting green pixelations on DECT on reader time, accuracy, and confidence.MethodsWe collected a sample of positive and negative DECTs, reviewed twice—once with and once without the DL tool—with a 2-week washout period. An attending musculoskeletal radiologist and a fellow separately reviewed the cases, simulating clinical workflow. Metrics such as time taken, confidence in diagnosis, and the tool's helpfulness were recorded and statistically analyzed.ResultsWe included thirty DECTs from different patients. The DL tool significantly reduced the reading time for the trainee radiologist (p = 0.02), but not for the attending radiologist (p = 0.15). Diagnostic confidence remained unchanged for both (p = 0.45). However, the DL model identified tiny MSU deposits that led to a change in diagnosis in two cases for the in-training radiologist and one case for the attending radiologist. In 3/3 of these cases, the diagnosis was correct when using DL.ConclusionsThe implementation of the developed DL model slightly reduced reading time for our less experienced reader and led to improved diagnostic accuracy. There was no statistically significant difference in diagnostic confidence when studies were interpreted without and with the DL model.

PURPOSE:Abnormal adherence at functional myofascial interfaces is hypothesized as an important phenomenon in myofascial pain syndrome. This study aimed to investigate the feasibility of MR elastography (MRE)-based slip interface imaging (SII) to visualize and assess myofascial mobility in healthy volunteers. METHODS:SII was used to assess local shear strain at functional myofascial interfaces in the flexor digitorum profundus (FDP) and thighs. In the FDP, MRE was performed at 90 Hz vibration to each index, middle, ring, and little finger. Two thigh MRE scans were performed at 40 Hz with knees flexed and extended. The normalized octahedral shear strain (NOSS) maps were calculated to visualize myofascial slip interfaces. The entropy of the probability distribution of the gradient NOSS was computed for the two knee positions at the intermuscular interface between vastus lateralis and vastus intermedius, around rectus femoris, and between vastus intermedius and vastus medialis. RESULTS:NOSS map depicted distinct functional slip interfaces in the FDP for each finger. Compared to knee flexion, clearer slip interfaces and larger gradient NOSS entropy at the vastus lateralis-vastus intermedius interface were observed during knee extension, where the quadriceps are not passively stretched. This suggests the optimal position for using SII to visualize myofascial slip interface in skeletal muscles is when muscles are not subjected to any additional force. CONCLUSION:The study demonstrated that MRE-based SII can visualize and assess myofascial interface mobility in extremities. The results provide a foundation for investigating the hypothesis that myofascial pain syndrome is characterized by changes in the mobility of myofascial interfaces.

Worldwide hunters distribute game meat as a gesture of community bonding and as an essential nutritional resource for those facing food insecurity, especially among children and adolescents. Nonetheless, the risk of lead (Pb) contamination from lead-based bullets is not widely acknowledged. Although medical radiography (X-ray) is the standard method to detect lead in meat donations, its efficacy in conclusively identifying lead contamination in game meat samples remains unknown. To address this deficiency, hunters-provided game meat samples were analyzed using both X-ray and inductively-coupled plasma mass spectrometry (ICP-MS). By ICP-MS, 48% of these samples contained lead levels exceeding the daily intake benchmarks for children, including the samples in which no lead was identified by X-ray screening. This finding means that food insecure individuals need to make an unenviable decision between risking lead exposure in donated meat or forgoing a potentially critical food source.

Motor-evoked potential (MEP) monitoring is an electrophysiologic technique useful for testing peripheral motor nerve integrity during cryoablation cases with risk of nerve injury. Previously, neuromonitoring within the magnetic resonance imaging (MRI) suite for cryoablation has not been performed as magnetic needles are used which could cause magnetic field interactions with neuromonitoring leads. We present the first report of a patient who underwent MEP monitoring during MRI-guided cryoablation of a vascular malformation adjacent to the brachial plexus. We demonstrate that MEPs may be safely and accurately performed by interleaving MRI and MEPs during treatment, reducing the risk of postprocedural complications.

Rationale and objectivesDual-energy CT (DECT) plays an important role in the evaluation of gout based on its ability to identify monosodium urate (MSU) crystals. Post-processing of DECT includes selection of a minimum Hounsfield unit (HU) threshold, currently set at 150 HU. Adjustments to this setting will affect the amount of MSU that is identified, with lower thresholds identifying more true and false positive MSU. The purpose of this study is to assess the performance of several HU thresholds.Materials and methods134 DECTs were reprocessed with minimum HU thresholds set to 150, 140, 130, and 120 HU. Volume of MSU detected was compared across thresholds. Subsequently, readers reviewed 3D axial images from 109 cases at 150, 130, and 120 HU thresholds. For each case, the reader made a diagnosis of gout, rated their confidence, and reported the location of MSU deposits.ResultsMean MSU volume detected was as follows: 0.160 at 150, 0.205 at 140, 0.276 at 130, and 0.444 at 120 HU. Based on reader diagnosis, there was no significant difference in sensitivity for the diagnosis of gout between the 150 (68.8%), 130 (71.8%), and 120 (69.7%) HU thresholds (p = 0.653). Specificity was higher at 150 HU (65.4%) than at 130 (58.4%) and 120 (52.2%), (p < 0.001). Mean reader confidence was 90.1 for 150 HU, 79.9 for 130 HU, and 74.0 for 120 HU (p < 0.001).ConclusionBetween the 150, 130, and 120 HU thresholds, 150 HU performed best overall for making the diagnosis of gout on DECT. Further research is needed to determine if there is utility for utilizing lower threshold settings for certain clinical scenarios.

Determine incidence of shoulder arthroplasty complications identified on computed tomography (CT). Retrospective institutional database review of patients with shoulder arthroplasties who underwent CT between 01/2006–11/2021 at a tertiary academic referral center with subspecialized orthopedic shoulder surgeons. CT reports were reviewed for arthroplasty type and complication. Data were stratified and summarized. Associations between complications and arthroplasty types were determined with Chi-squared goodness of fit test. Eight hundred twelve CTs in 797 unique patients were included (438 (53.9

The feasibility of low-dose photon-counting detector (PCD) CT to measure alpha and acetabular version angles of femoroacetabular impingement (FAI). FAI patients undergoing an energy-integrating detector (EID) CT underwent an IRB-approved prospective ultra-high-resolution (UHR) PCD-CT between 5/2021 and 12/2021. PCD-CT was dose-matched to the EID-CT or acquired at 50

Osteoid osteomas typically arise in the long bones of extremities. Patients often report pain relieved by NSAIDS, and radiographic findings are often sufficient for diagnosis. However, when involving the hands/feet, these lesions may go unrecognized or misdiagnosed radiographically due to their small size and prominent reactive changes. The clinicopathologic features of this entity involving the hands and feet are not well-described. Our institutional and consultation archives were searched for all cases of pathologically confirmed osteoid osteomas arising in the hands and feet. Clinical data was obtained and recorded. Seventy-one cases (45 males and 26 females, 7 to 64 years; median 23 years) arose in the hands and feet, representing 12% of institutional and 23% of consultation cases. The clinical impression often included neoplastic and inflammatory etiologies. Radiology studies demonstrated a small lytic lesion in all cases (33/33), the majority of which had a tiny focus of central calcification (26/33). Nearly, all cases demonstrated cortical thickening and/or sclerosis and perilesional edema which almost always had an extent two times greater than the size of the nidus. Histologic examination showed circumscribed osteoblastic lesions with formation of variably mineralized woven bone with single layer of osteoblastic rimming. The most common growth pattern of bone was trabecular (n = 34, 48%) followed by combined trabecular and sheet-like (n = 26, 37%) with only 11 (15%) cases presenting with pure sheet-like growth pattern. The majority (n = 57, 80%) showed intra-trabecular vascular stroma. No case showed significant cytology atypia. Follow up was available for 48 cases (1-432 months), and 4 cases recurred. Osteoid osteomas involving the hands and feet follow a similar age and sex distribution as their non-acral counterparts. These lesions often present with a broad differential diagnosis and may initially be confused with chronic osteomyelitis or a reactive process. While the majority of cases have classic morphologic features on histologic exam, a small subset consists solely of sheet-like sclerotic bone. Awareness that this entity may present in the hands and feet will help pathologists, radiologists, and clinicians accurately diagnose these tumors.

PURPOSE:MRI has become an essential diagnostic imaging modality for peripheral nerve pathology. Early MR imaging for peripheral nerve depended on inferred nerve involvement by visualizing downstream effects such as denervation muscular atrophy; improvements in MRI technology have made possible direct visualization of the nerves. In this paper, we share our early clinical experience with 7T for benign neurogenic tumors.MATERIALS:Patients with benign neurogenic tumors and 7T MRI examinations available were reviewed. Cases of individual benign peripheral nerve tumors were included to demonstrate 7T MRI imaging characteristics. All exams were performed on a 7T MRI MAGNETOM Terra using a 28-channel receive, single-channel transmit knee coil.RESULTS:Five cases of four pathologies were selected from 38 patients to depict characteristic imaging features in different benign nerve tumors and lesions using 7T MRI.CONCLUSION:The primary advantage of 7T over 3T is an increase in signal-to-noise ratio which allows higher in plane resolution so that the smallest neural structures can be seen and characterized. This improvement in MR imaging provides the opportunity for more accurate diagnosis and surgical planning in selected cases. As this technology continues to evolve for clinical purposes, we anticipate increasing applications and improved patient care using 7T MRI for the diagnosis of peripheral nerve masses.

Describe imaging features of intraosseous hemangiomas located outside of the mobile spine and calvarium. Imaging and medical records were retrospectively reviewed for cases of intraosseous hemangiomas located outside of the calvarium and mobile spine. Evaluation included patient demographics, histologic confirmation, and imaging characteristics. Thirty-six patients were included (25 F, 11 M; mean age 54 ± 17 years, range 10–84 years) with 37 total lesions (70

This review illustrates the imaging features of rhabdomyolysis across multiple modalities and in a variety of clinical scenarios. Rhabdomyolysis is the rapid breakdown of striated muscle following severe or prolonged insult resulting in the release of myocyte constituents into circulation. In turn, patients develop characteristically elevated serum creatine kinase, positive urine myoglobin, and other serum and urine laboratory derangements. While there is a spectrum of clinical symptoms, the classic presentation has been described as muscular pain, weakness, and dark urine. This triad, however, is only seen in about 10% of patients. Thus, when there is a high clinical suspicion, imaging can be valuable in evaluating the extent of muscular involvement, subsequent complications such as myonecrosis and muscular atrophy, and other etiologies or concurrent injuries causing musculoskeletal swelling and pain, especially in the setting of trauma. Sequela of rhabdomyolysis can be limb or life-threatening including compartment syndrome, renal failure, and disseminated intravascular coagulation. MRI, CT, ultrasound, and 18-FDG PET/CT are useful modalities in the evaluation of rhabdomyolysis.

Abstract Familial expansile osteolysis is an exceedingly rare autosomal dominant bone dysplasia, which can have overlapping features with Paget disease and expansile skeletal hyperphosphatasia. We present a novel case of familial expansile osteolysis evaluated on 99mTc-MDP bone scan with correlative radiographs and CT.

ABSTRACT:Familial expansile osteolysis is an exceedingly rare autosomal dominant bone dysplasia, which can have overlapping features with Paget disease and expansile skeletal hyperphosphatasia. We present a novel case of familial expansile osteolysis evaluated on 99mTc-MDP bone scan with correlative radiographs and CT.

ABSTRACT PET/CT plays a crucial role in the management of prostate cancer with several emerging and established radiopharmaceuticals, including 18F-piflufolastat and 11C-choline. These radiotracers are thought to be relatively specific to prostate cancer; however, uptake has also been demonstrated in other benign and malignant lesions. Nodular fasciitis is a rapidly growing benign soft tissue neoplasm that is typically self-limiting. Although a few case reports describe 68Ga-PSMA uptake in nodular fasciitis, uptake of 11C-choline and other PSMA-targeted PET probes, including 18F-piflufolastat, have not previously been reported. We present a novel case of nodular fasciitis demonstrating both 18F-piflufolastat and 11C-choline avidity.

OBJECTIVE:To determine the accuracy of preoperative ultrasound and MRI in surgically confirmed spinal accessory nerve injuries and present the benefits of a multimodality image review.MATERIALS AND METHODS:A retrospective review of 38 consecutive patients referred to a peripheral nerve surgical practice at an academic teaching hospital with surgically confirmed spinal accessory nerve injuries. All cases were reviewed for patient demographics, date and cause of injury, preoperative EMG, and surgical diagnosis and management. Additionally, prospective interpretation of preoperative ultrasound and MRI reports were reviewed for concordance or discordance with the surgical diagnosis.RESULTS:Iatrogenic injury was present in 37 (97%) cases and most commonly a result of an excisional lymph node biopsy (68%). Surgically confirmed spinal accessory nerve injury diagnoses consisted of 25 (66%) stump neuromas and 13 (34%) incomplete nerve injuries. Nine months was the average time from injury to surgery. Twenty-nine patients underwent preoperative ultrasound and/or MRI evaluation: 12 ultrasound only, 10 MRI only, and seven with both ultrasound and MRI. Eighteen (95%) preoperative ultrasound reports compared to four (24%) preoperative MRI reports were concordant with the surgical diagnosis. In the seven cases with both preoperative ultrasound and MRI, six had discordant ultrasound and MRI imaging diagnoses for which the ultrasound was concordant with the surgical diagnoses in all cases.CONCLUSION:Preoperative ultrasound more accurately characterizes spinal accessory nerve injuries compared to MRI and should serve as the modality of choice when a spinal accessory nerve injury is suspected.

This review illustrates the multimodality assessment of transfascial muscle and other soft tissue herniations of the extremities. Transfascial herniations of the extremities can develop from congenital or acquired disruptions of the deep fascia, resulting in herniation of the underlying muscle, nerve, or soft tissue tumor into the subcutaneous tissues. While most patients present with a painless subcutaneous nodule that may change in size with muscle activation, some may experience focal or diffuse extremity symptoms such as pain and paresthesias. Although the diagnosis may be clinically suspected, radiologic evaluation is useful for definitive diagnosis and characterization. Ultrasound is the preferred modality for initial workup through a focused and dynamic examination. Magnetic resonance imaging can be utilized for equivocal, complicated, and preoperative cases. Computed tomography is less useful in the evaluation of transfascial herniations in the extremities due to similarities in the attenuation between muscle and fascia, which can decrease the conspicuity of small defects.