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Objective: To develop machine learning models using patient and migraine features that can predict treatment responses to commonly used migraine preventive medications., Background: Currently, there is no accurate way to predict response to migraine preventive medications, and the standard trial-and-error approach is inefficient., Methods: In this cohort study, we analyzed data from the Mayo Clinic Headache database prospectively collected from 2001 to December 2023. Adult patients with migraine completed questionnaires during their initial headache consultation to record detailed clinical features and then at each follow-up to track preventive medication changes and monthly headache days. We included patients treated with at least one of the following migraine preventive medications: topiramate, beta-blockers (propranolol, metoprolol, atenolol, nadolol, timolol), tricyclic antidepressants (amitriptyline, nortriptyline), verapamil, gabapentin, onabotulinumtoxinA, and calcitonin gene-related peptide (CGRP) monoclonal antibodies (mAbs) (erenumab, fremanezumab, galcanezumab, eptinezumab). We pre-trained a deep neural network, "TabNet," using 145 variables, then employed TabNet-embedded data to construct prediction models for each medication to predict binary outcomes (responder vs. non-responder). A treatment responder was defined as having at least a 30% reduction in monthly headache days from baseline. All model performances were evaluated, and metrics were reported in the held-out test set (train 85%, test 15%). SHapley Additive exPlanations (SHAP) were conducted to determine variable importance., Results: Our final analysis included 4260 patients. The responder rate for each medication ranged from 28.7% to 34.9%, and the mean time to treatment outcome for each medication ranged from 151.3 to 209.5 days. The CGRP mAb prediction model achieved a high area under the receiver operating characteristics curve (AUC) of 0.825 (95% confidence interval [CI] 0.726, 0.920) and an accuracy of 0.80 (95% CI 0.70, 0.88). The AUCs of prediction models for beta-blockers, tricyclic antidepressants, topiramate, verapamil, gabapentin, and onabotulinumtoxinA were: 0.664 (95% CI 0.579, 0.745), 0.611 (95% CI 0.562, 0.682), 0.605 (95% CI 0.520, 0.688), 0.673 (95% CI 0.569, 0.724), 0.628 (0.533, 0.661), and 0.581 (95% CI 0.550, 0.632), respectively. Baseline monthly headache days, age, body mass index (BMI), duration of migraine attacks, responses to previous medication trials, cranial autonomic symptoms, family history of headache, and migraine attack triggers were among the most important variables across all models. A variable could have different contributions; for example, lower BMI predicts responsiveness to CGRP mAbs and beta-blockers, while higher BMI predicts responsiveness to onabotulinumtoxinA, topiramate, and gabapentin., Conclusion: We developed an accurate prediction model for CGRP mAbs treatment response, leveraging detailed migraine features gathered from a headache questionnaire before starting treatment. Employing the same methods, the model performances for other medications were less impressive, though similar to the machine learning models reported in the literature for other diseases. This may be due to CGRP mAbs being migraine-specific. Incorporating medical comorbidities, genomic, and imaging factors might enhance the model performance. We demonstrated that migraine characteristics are important in predicting treatment responses and identified the most crucial predictors for each of the seven types of preventive medications. Our results suggest that precision migraine treatment is feasible., (© 2024 American Headache Society.)

Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Dual-energy CT (DECT) is an exciting application in CT technology conferring many advantages over conventional single-energy CT at no additional with comparable radiation dose to the patient. Various emerging and increasingly established clinical DECT applications in musculoskeletal (MSK) imaging such as bone marrow oedema detection, metal artefact reduction, monosodium urate analysis, and collagen analysis for ligamentous, meniscal, and disc injuries are made possible through its advanced DECT post-processing capabilities. These provide superior information on tissue composition, artefact reduction and image optimization. Newer DECT applications to evaluate fat fraction for sarcopenia, Rho/Z application for soft tissue calcification differentiation, 3D rendering, and AI integration are being assessed for future use. In this article, we will discuss the established and developing applications of DECT in the setting of MSK radiology as well as the basic principles of DECT which facilitate them., (© The Author(s) 2024. Published by Oxford University Press on behalf of the British Institute of Radiology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Purpose: To determine the sensitivity and specificity of dual-energy CT (DECT) virtual noncalcium images (VNCa) with bone and soft tissue reconstructions in the diagnosis of osteomyelitis. Materials & Methods: Between December 1, 2014 to December 1, 2020, 91 patients who had 99 DECT performed for a clinical indication of osteomyelitis with corresponding MRI, triphasic bone scan and/or white blood cell scintigraphy with CT/SPECT performed either 2 weeks before or 1 month after the DECT were retrospectively identified. The presence or absence of osteomyelitis was established using a second imaging test, bone biopsy or surgery. Two radiologists interpreted VNCa images alone and with bone and soft tissue reconstructions for osteomyelitis. Fleiss k statistics was used to assess inter-level agreement. Results: Osteomyelitis was present in 26 cases (26.2%), of which 4 cases (4%) had co-existing septic arthritis. DECT was performed at the following sites: ankle/foot (n = 59), calf (n = 12), knee (n = 3), thigh (n = 7), hip (n = 9), pelvis (n = 6), wrist/hand (n = 1), and shoulder (n = 2). Sensitivity with VNCa images alone was 53.8% and 73.1% and specificity was 84.9% and 71.2%. Sensitivity with VNCa images and bone and soft tissue reconstructions was 80.8% and 80.8% and specificity was 80.8% and 72.6%. Interobserver agreement was 76.7% (76 of 99 cases), for VNCa images alone (k = .487), and 66.7% (66 of 99 patients) for bone and soft tissue reconstructions with VNCa images together (k = .390). Conclusion: When VNCa images were combined with bone and soft tissue reconstructions, there is improved sensitivity in the diagnosis of osteomyelitis.

Periarticular calcification and ossification is a frequent finding on imaging and may sometimes pose a diagnostic challenge. The differential diagnoses for this radiological finding are wide and can be classified into broad groups such as idiopathic, developmental, trauma, burns, infection, tumor, connective tissue disease, crystalline, metabolic, vascular, and foreign bodies. With careful consideration of the clinical and imaging findings as well as awareness of mimickers of periarticular mineralization, the list of differential diagnoses can be narrowed down. This article aims to review the clinical-radiologic findings of periarticular calcified or ossified lesions with relevant imaging illustrations., (© 2021. ISS.)

A nuchal-type fibroma is a rare, benign fibrous tumour that typically occurs in the posterior neck along the midline, but can occur in extra-nuchal locations, most commonly in the back, shoulder and face. We present a biopsy-proven case that arose as a result of heavy gym-related activities. In particular, a heavy barbell was rested on his vertebral prominence at the level of C7/T1 during leg squatting. Repetitive trauma as a cause for extra-nuchal-type fibromas has been sparsely reported, but we suggest that sustained high pressure is an additional required feature. Although this lesion was in the posterior neck, it was contained entirely within the subcutaneous tissues without involvement of the nuchal ligament. Hence, it was considered an extra-nuchal fibroma. A description of key ultrasound and MRI imaging characteristics are provided to assist in making the diagnosis, along with a review of the current literature and a discussion of differential diagnoses., (© 2021. ISS.)

Competing Interests: Disclosure The authors report no conflicts of interest in this work.

Hockey is a demanding contact sport with growing popularity around the world. This article is part of a review series in this issue of Seminars in Musculoskeletal Radiology that summarizes epidemiological research on the patterns of ice hockey injuries as well as provides pictorial examples for a radiologist's perspective. We focus on non-extremity pathologies which encompass many of the most devastating injuries of hockey, namely those involving the head, neck, face, spine, and body., Competing Interests: None declared., (Thieme. All rights reserved.)

Ice hockey is a fast-paced contact sport with a high incidence of injuries. Upper extremity injury is one of the most common regions of the body to be injured in hockey. This imaging review will equip the radiologist with a knowledge of the more common and severe upper extremity injuries that occur in this sport., Competing Interests: None declared., (Thieme. All rights reserved.)

Hockey is a fast-paced contact sport with a high incidence of injuries. Although injuries are more frequent among elite players, recreational hockey injuries are a common issue faced by primary care and emergency physicians. Lower extremity injuries in hockey are particularly important because they account for approximately a third of all injuries and > 60% of all overuse injuries. This pictorial review provides the general and specialty trained radiologist with a knowledge of the patterns of lower extremity injury that occur in ice hockey., Competing Interests: None declared., (Thieme. All rights reserved.)

Introduction: Desmoid tumor is a locally-invasive neoplasm that causes significant morbidity. There is recent interest in cryotherapy for treatment of extra-abdominal desmoid tumors. This systematic review assesses evidence on safety and efficacy of cryotherapy in the treatment of extra-abdominal desmoid tumors., Materials and Methods: The systematic review was conducted with reference to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Literature search was performed using MEDLINE and the Cochrane Central Register of Controlled Trials. 9 full text papers were reviewed and meta-analysis was performed for measures of safety, efficacy and symptom relief., Results: The estimated pooled proportion of major and minor complications was 4.2% (95% CI, 1.8-9.6; I 2 = 0%) and 10.2% (95% CI, 5.7-17.8; I 2 = 0%) respectively. The estimated pooled proportion of non-progressive disease rate of all studies was 85.8% (95% CI, 73.4-93.0; I 2 = 32.9%). The estimated progression free survival rate at 1 year was 84.5% (95% CI:74.6-95.8) and 78.0% at 3 years (95% CI: 63.8-95.3). As for pain control, the estimated pooled proportion of patients with decrease in visual analogue scale (VAS) > = 3 for those with VAS > = 3 before treatment for 2 studies was 87.5% (95% CI, 0.06-100; I 2 = 71.5%) while 37.5% to 96.9% of patients were reported to have experienced partial or complete symptom relief in the other studies., Conclusion: Cryotherapy is a safe and effective treatment modality for extra-abdominal desmoid tumors with efficacy similar to those treated with traditional strategies in the short to medium term., Competing Interests: The authors have declared that no competing interests exist.

Purpose: To determine the efficacy and safety of cryoablation in patients with desmoid tumors (DTs) retrospectively over a 10-year period at a single institution., Materials and Methods: Between February 25, 2010, and February 25, 2020, 25 patients (age, 12-80 years) with 26 lesions (mean preprocedural tumor volume was 237 cm 3 ) were treated over 44 cryoablation procedures. Eleven patients were treated with first-line therapy. Fourteen patients had previous medical therapy, radiotherapy, and/or surgery. Subsequent clinical follow-up, imaging outcomes, and safety were analyzed for technical success, change in total lesion volume (TLV) and viable tumor volume (VTV), modified response evaluation criteria in solid tumors (mRECIST), progression-free survival (PFS) for tumor progression and symptom recurrence, symptom improvement, and procedure-related complications. Symptomatic improvement was defined as documentation of relief of pain (partial or complete) and/or functional impairment., Results: All procedures were technically successful. At 7-12 months, median changes in TLV and VTV were -6.7% (P = .809) and -43.7% (P = .01), respectively. At 10-12 months, the mRECIST responses were complete response, 0%; partial response, 61.5% (8/13); stable disease, 30.8% (4/13); and progressive disease, 7.7% (1/13). The median PFS for tumor progression and symptom recurrence were not reached, with a median follow-up of 15.3 and 21.0 months, respectively. Symptomatic relief (partial or complete) was achieved in 96.9% (32/33) of patients. One major complication was noted (2.4%)., Conclusions: In this retrospectively identified cohort, cryoablation was effective and safe for the local control of extra-abdominal DTs in short-term follow-up., (Copyright © 2021 SIR. Published by Elsevier Inc. All rights reserved.)

Patellofemoral syndrome (PFS) is a common etiology of anterior knee pain, particularly among young female athletes. Despite recent advancements in the resolution of MRI, there still remains a paucity of literature that has investigated the MRI findings associated with PFS. This pictorial essay will describe our institution's experience with cases of PFS and review what we believe to be a constellation of findings associated with this diagnostic entity. This review will also describe common pitfalls encountered during the diagnosis of PFS.

Purpose: Location, size, and local inflammatory findings in primary epiploic appendagitis (EA) have not been reported outside of small studies. The association between EA and increased adiposity is controversial. The goals of this project are to compare demographics and imaging-based measurements of adiposity between patients with EA and patients with acute abdomen without EA, and to identify CT features of EA., Methods: A consecutive sample of acute, primary EA (n = 100), and control (acute abdomen; n = 100) was selected retrospectively. Cases of suspected EA were included if they had the characteristic ovoid fatty mass and hyperattenuated ring sign on CT. Abdominal adipose volume (AAV), visceral adipose area (VAA), and subcutaneous adipose area (SAA) were quantified by CT. Location, size, and frequency of coexisting local inflammatory findings in EA patients were recorded., Results: EA had 60% greater AAV, 117% greater VAA, and 35% greater SAA than control subjects (p < 0.0001). Males composed a great proportion of the EA group (67%) than the control group (41%) (p = 0.0002). Inflamed appendage was found in sigmoid colon in 49% of cases, descending colon in 23%, and right colon in 19%. Peritoneal thickening was frequent (76%) and bowel wall thickening was common (47%). Diverticulosis coexisted incidentally in 28%., Conclusion: EA is associated with increased abdominal adipose tissue. EA can occur in both sexes at any age, but occurs at age 50 on average and more frequently in males. Patient with EA exhibited central hyperdense dot (79%), peritoneal thickening (76%), and bowel wall thickening (47%).

Background: Metastases to the bone are common in cancer patients, and it has been estimated that up to 50% of patients with pelvic bone metastases will not achieve adequate pain control with medications alone. This has led to a paradigm shift over recent years towards the use and development of minimally invasive image-guided treatment options for palliation of bony metastases. Despite these developments, large metastatic lesions are still often considered to be "hopeless cases" that would garner little to no benefit from image-guided intervention. This study is the first large series to describe the novel use of combination percutaneous cryoablation and cementoplasty for palliation of such large metastases to the pelvis., Objectives: We aim to evaluate the efficacy and safety of image-guided percutaneous cryoablation and cementoplasty for palliation of large pelvic bone metastases., Study Design: This retrospective analysis was approved by our institutional review board. This study was conducted from January 2013 to December 2016, where consecutive patients referred for pain management of large pelvic bone metastases underwent combination percutaneous cryoablation and cementoplasty., Setting: This study took place at a tertiary care center after patients were referred following formal review from a multidisciplinary conference, which was comprised of interventional radiologists, pain management and palliative care physicians, radiation and medical oncologists, and when available, anesthesiologists., Methods: Forty-eight patients (36 men and 12 women) with a mean cohort age of 77.5 years (range: 52 - 89 years) were referred from the multidisciplinary conference for palliation of pelvic bone metastases. The inclusion criteria included patients with metastases greater or equal to 5.0 cm and significant pain refractory to conventional pain management regimens. All of the patients were deemed not to be surgical candidates. Mean pain scores were collected at numerous time-points along with procedural technical success rates and complication rates., Results: Combination cryoablation and cementoplasty was performed on 48 consecutively referred patients with a 100% technical success rate and no immediate complications. The pain levels demonstrated a significant decrease (P < 0.001) following intervention, with mean pain scores of 7.9 (range: 5 - 10) and 1.2 (range: 0 - 7) throughout the week prior to intervention and at 24 hours post-intervention, respectively. The post-intervention pain scores remained stable at 1 to 9 weeks follow-up (mean: 4.1 weeks). Three patents (6.3%) reported no change in pain following the intervention; however, no patients reported worsened pain., Limitations: The limitations of this study include its retrospective nature and the length of follow-up, which was often restricted given the life expectancy of our patient cohort., Conclusion: Combination cryoablation and cementoplasty is a novel and efficacious treatment option for palliation of large pelvic bone metastases. Marked improvements in pain, as well as mobility and quality of life, are often attainable., Key Words: Pain, palliative care, palliation, percutaneous, cryoablation, cementoplasty, metastases, pelvis, interventional radiology, thermal ablation.

Purpose To quantify the sensitivity and specificity of dual-energy computed tomographic (CT) virtual noncalcium images in the detection of nondisplaced hip fractures and to assess whether obtaining these images as a complement to bone reconstructions alters sensitivity, specificity, or diagnostic confidence. Materials and Methods The clinical research ethics board approved chart review, and the requirement to obtain informed consent was waived. The authors retrospectively identified 118 patients who presented to a level 1 trauma center emergency department and who underwent dual-energy CT for suspicion of a nondisplaced traumatic hip fracture. Clinical follow-up was the standard of reference. Three radiologists interpreted virtual noncalcium images for traumatic bone marrow edema. Bone reconstructions for the same cases were interpreted alone and then with virtual noncalcium images. Diagnostic confidence was rated on a scale of 1 to 10. McNemar, Fleiss κ, and Wilcoxon signed-rank tests were used for statistical analysis. Results Twenty-two patients had nondisplaced hip fractures and 96 did not have hip fractures. Sensitivity with virtual noncalcium images was 77% and 91% (17 and 20 of 22 patients), and specificity was 92%-99% (89-95 of 96 patients). Sensitivity increased by 4%-5% over that with bone reconstruction images alone for two of the three readers when both bone reconstruction and virtual noncalcium images were used. Specificity remained unchanged (99% and 100%). Diagnostic confidence in the exclusion of fracture was improved with combined bone reconstruction and virtual noncalcium images (median score: 10, 9, and 10 for readers 1, 2, and 3, respectively) compared with bone reconstruction images alone (median score: 9, 8, and 9). Conclusion When used as a supplement to standard bone reconstructions, dual-energy CT virtual noncalcium images increased sensitivity for the detection of nondisplaced traumatic hip fractures and improved diagnostic confidence in the exclusion of these fractures. © RSNA, 2017 Online supplemental material is available for this article. An earlier incorrect version of this article appeared online. This article was corrected on March 17, 2017.

Throughout recent years, Gabapentin has become increasingly used for the treatment of neuropathic pain. We report on a case of a 31 year old female who presented to the emergency department with unilateral leg pain, weakness, and swelling after increasingly titrating her Gabapentin dosage over three weeks. Magnetic resonance imaging confirmed the presence of myositis confined to the left thigh and the patient's symptoms and laboratory abnormalities resolved following Gabapentin cessation. While Gabapentin-induced myositis and rhabdomyolysis is a rare entity, it should be a diagnostic consideration for radiologists, particularly in the absence of infection or trauma.

The principal advantages of dual-energy computed tomography (CT) over conventional CT in the musculoskeletal setting relate to the additional information provided regarding tissue composition, artifact reduction, and image optimization. This article discusses the manifestations of these in clinical practice-urate and bone marrow edema detection, metal artifact reduction, and tendon analysis, with potential in arthrography, bone densitometry, and metastases surveillance. The basic principles of dual-energy CT physics and scanner design will also be discussed. © RSNA, 2016.

Objective: Dual-energy CT (DECT) is an innovative imaging modality that allows superior detection of pulmonary embolism, enhanced detection of urate in gout, and improved assessment of metal prostheses when compared with conventional CT., Conclusion: The primary aim of this review is to describe these DECT protocols and compare each to its respective diagnostic reference standards. Moreover, this review will describe how to recognize, reduce, and eliminate DECT artifacts, thereby maximizing its diagnostic capabilities.

Advances in reconstructive orthopaedic techniques now allow for limb salvage and prosthetic reconstruction procedures to be performed on patients who would otherwise be required to undergo debilitating limb amputations for malignant bone tumours. The resulting post-operative imaging of such cases can be daunting for the radiologist to interpret, particularly in the presence of distorted anatomy and unfamiliar hardware. This article reviews the indications for limb salvage surgery, prosthetic reconstruction devices involved, expected post-operative imaging findings, as well as the potential hardware related complications that may be encountered in the management of such cases., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

The purpose of this study is to describe our initial clinical experience with dual-energy computed tomography (DECT) virtual non-calcium (VNC) images for the detection of bone marrow (BM) edema in patients with suspected hip fracture following trauma. Twenty-five patients presented to the emergency department at a level 1 trauma center between January 1, 2011 and January 1, 2013 with clinical suspicion of hip fracture and normal radiographs were included. All CT scans were performed on a dual-source, dual-energy CT system. VNC images were generated using prototype software and were compared to regular bone reconstructions by two musculoskeletal radiologists in consensus. Radiological and/or clinical diagnosis of fracture at 30-day follow-up was used as the reference standard. Twenty-one patients were found to have DECT-VNC signs of bone marrow edema. Eighteen of these 21 patients were true positive and three were false positive. A concordant fracture was clearly seen on bone reconstruction images in 15 of the 18 true positive cases. In three cases, DECT-VNC was positive for bone marrow edema where bone reconstruction CT images were negative. Four patients demonstrated no DECT-VNC signs of bone marrow edema: two cases were true negative, two cases were false negative. When compared with the gold standard of hip fracture determined at retrospective follow-up, the sensitivity of DECT-VNC images of the hip was 90 %, specificity was 40 %, positive predictive value was 86 %, and negative predictive value was 50 %. Our initial experience would suggest that DECT-VNC is highly sensitive but poorly specific in the diagnosis of hip fractures in patients with normal radiographs. The value of DECT-VNC primarily lies in its ability to help detect fractures which may be subtle or undetectable on bone reconstruction CT images.

Computed tomography (CT) is often used to assess the presence of occult fractures when plain radiographs are equivocal in the acute traumatic setting. While providing increased spatial resolution, conventional computed tomography is limited in the assessment of bone marrow edema, a finding that is readily detectable on magnetic resonance imaging (MRI).Dual-energy CT has recently been shown to demonstrate patterns of bone marrow edema similar to corresponding MRI studies. Dual-energy CT may therefore provide a convenient modality for further characterizing acute bony injury when MRI is not readily available. We report our initial experiences of 4 cases with imaging and clinical correlation.

Purpose: This technical note describes the novel use of a curved, steerable needle to access symptomatic osseous lesions in the pelvis and sacrum for palliative percutaneous treatment that would otherwise be difficult to treat using conventional straight needles., Materials and Methods: Seven patients with lytic bone lesions were treated. One patient had multiple myeloma; the remaining had metastatic disease: breast carcinoma (n = 2), colorectal carcinoma (n = 1), renal cell carcinoma (n = 1), squamous cell carcinoma (n = 1), and leiomyosarcoma (n = 1). Five of the seven patients had lesions in the posterior acetabulum, and the two other patients had lesions in the sacrum. Four of the seven patients received radiofrequency ablation followed by cementoplasty; three patients received cementation alone. We used a novel needle designed for vertebroplasty, which has an articulating tip allowing it to be guided into lytic bone lesions located in difficult-to-access regions of the pelvis and sacrum., Results: All patients were successfully treated with cementoplasty either with or without thermal ablation. No serious adverse events were reported. The needle was difficult to withdraw in two patients., Conclusion: Steerable curved needles can be successfully used to treat lytic osseous metastases with cementoplasty when lesions are located in sites that may be difficult to reach using conventional straight needles.

Vertebroplasty is a cost-effective procedure for the relief of pain in appropriately selected patients when performed by a skilled practitioner. The currently accepted indications and contraindications for vertebroplasty are reviewed. The techniques routinely used by the authors are presented, including a discussion of recognized complications. Recent controversy has highlighted weaknesses in the practice of technology evaluation, and more robust studies will be required to address these issues across the board in the future more scientifically than has been done in the past., (Copyright © 2012 Canadian Association of Radiologists. Published by Elsevier Inc. All rights reserved.)

Acetabuloplasty is a valuable palliative adjunct for the treatment of patients with painful metastatic disease to the pelvis in selected cases. We report the case of a 45-year-old woman with morbid obesity and with breast carcinoma who was technically difficult to treat under fluoroscopic guidance due to very poor visualization secondary to her body habitus. It was possible to perform radiofrequency ablation and acetabuloplasty with the use of cone-beam computed tomography for guidance., (Copyright © 2012 Canadian Association of Radiologists. Published by Elsevier Inc. All rights reserved.)

Objective: The purpose of this article is to describe the imaging appearances of musculoskeletal injuries related to yoga. We performed an automated search in the database of a large tertiary care center and conducted a retrospective analysis of the imaging findings in 38 patients over a 9-year period., Conclusion: The most frequently encountered musculoskeletal injuries were tendinous lesions, including tears of the supraspinatus, Achilles, and peroneus brevis tendons and fibrocartilaginous tears involving the medial meniscus, acetabular labrum, glenoid labrum, and lumbar disk with extrusion.

Objective: Evaluate the efficacy of percutaneous vertebroplasty for severe vertebral body compression fractures., Methods: Over a period of 6 years and 8 months, 661 vertebroplasties were performed in 292 patients at our institution. Of these, 69 patients met our criteria for a severe vertebral body compression fracture defined as vertebral body collapse to less than one-third of the original height. Of the 69, 25 underwent single level vertebroplasty. Imaging features were then analyzed including location, extent of collapse, pattern of compression, pre- and post-kyphotic angle and adjacent disc height. Complications and clinical outcomes were then evaluated., Results: Involved vertebra ranged from T6 to L5 with 60% at the thoracolumbar junction. Vertebral body collapse ranged from 30 to 14% (mean 22%) of original height. Pattern of collapse included 11/ 25 (44%) plana, 8/25 (32%) gibbus, and 6/25 (24%) H-shaped. Kyphotic angle before vertebroplasty ranged from 33-0° (mean 16°) with an average correction of 1.2° after vertebroplasty. Mean disc height before vertebroplasty was 7.3 mm above and 7.7 mm below. Complications included cement leak to the adjacent disc in 16 (64%) and the paravertebral soft tissues in 3 (12%). Cement leak into the proximal azygous vein was documented in one case. International Quality of Life Questionnaire VAS was completed before and after (6 weeks) the procedure by all but six patients. Mean pre-intervention VAS was reported as 7.00 (range 5-10, SD 1.73) and mean post-intervention VAS was reported as 5.11 (range 0-9, SD 2.56), demonstrating a statistically significant improvement in pain (P < 0.015, 95% CI = 0.83-2.96) with 84% or 16/19 patients reporting some degree of improvement., Conclusion: Percutaneous vertebroplasty is safe and effective in the treatment of single level severe vertebral body compression fractures.

Biomechanics are central in understanding the pathophysiology and magnetic resonance (MR) imaging of overhead throwing athlete injuries. Repetitive excessive valgus forces at the elbow result in characteristic injuries due to medial joint distraction, lateral joint compression, and rotatory forces at the olecranon. MR imaging is useful for assessment of the throwing elbow in adults., ((c) Thieme Medical Publishers.)

Objective: To compare breath-hold 1H-magnetic resonance spectroscopy (1H-MRS) with respiratory-gated 1H-MRS and computed tomography (CT) for quantification of hepatic lipid content., Methods: Twenty-three premenopausal women underwent breath-hold point-resolved single-voxel 1H-MRS of the liver followed by respiratory-gated 1H-MRS at 3 Tesla and CT slice through the liver. Interscan variability for 1H-MRS was assessed in 6 volunteers. Pearson correlation coefficients, Bland-Altman 95% limit of agreement, and concordance correlation coefficients were calculated., Results: There was a strong correlation between breath-hold and respiratory-gated 1H-MRS (r = 0.94, P < 0.0001; concordance correlation coefficient, 0.75). Using Bland-Altman analysis, all but 2 data points were within the limits of agreement. Both 1H-MRS techniques had low interscan variability. There was an inverse correlation of both 1H-MRS techniques with CT attenuation values of the liver., Conclusions: Breath-hold 1H-MRS is a reliable method to measure hepatic lipid content at 3 Tesla. Breath-hold 1H-MRS of the liver provides data that closely correlates with that obtained from longer-duration respiratory-gated technique.

Objective: To describe the correlation between medial patellar ossification and prior patella subluxation and/or dislocation., Materials and Methods: A retrospective billing database search identified 544 patients who had been diagnosed with patellar instability over a 13-year period. One hundred twenty-eight patients met the inclusion criteria. After review by a staff orthopedic surgeon and two musculoskeletal radiologists, 28 patients were found to have medial patellar ossification. The size and location of medial patellar ossification was recorded., Results: Of the 28 patients (20 males, eight females, age 13-66 years, mean 28 years) who were found to have medial patellar ossification, 22 had radiographs, 16 had magnetic resonance imaging, and ten had both. The medial patellar ossification ranged in size from 2 to 18 mm with an average of 6.8 mm. Twelve were located in the medial patellofemoral ligament (MPFL), 14 in the medial joint capsule, and two in both the MPFL and joint capsule. Twenty-seven of 28 patients had a single ossification, and one patient had two ossifications. The timing from injury to first imaging of the lesion ranged from 10 days to a chronic history (> or = 35 years) of patellar instability., Conclusion: Medial patellar ossification correlates with a history of prior patella subluxation and/or dislocation. The medial ossification can be seen within the MPFL or the medial joint capsule, suggesting remote injury to these structures. The presence of this lesion will prompt physicians to evaluate for patellar instability.

Objective: The objective was to evaluate the use of fluorodeoxyglucose positron emission tomography (FDG-PET) in differentiating benign from malignant compression fractures., Patients and Methods: In a retrospective analysis, we identified 33 patients with 43 compression fractures who underwent FDG-PET. On FDG-PET the uptake pattern was recorded qualitatively and semiquantitatively and fractures were categorized as benign or malignant. Standardized uptake values (SUV) were obtained. MRI, CT, and biopsy results as well as clinical follow-up for 1-3 years served as standards of reference. The Student's t test was used to determine whether there was a statistically significant difference between the SUV for benign and malignant compression fractures., Results: There were 14 malignant and 29 benign compression fractures, including 5 acute benign fractures. On FDG-PET, 5 benign fractures were falsely classified as malignant (false-positive). Three of these patients underwent prior treatment with bone marrow-stimulating agents. There were two false-negative results. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of FDG-PET in differentiating benign from malignant compression fractures were 86%, 83%, 84%, 71%, and 92% respectively. The difference between SUV values of benign and malignant fractures was statistically significant (1.9 +/- 0.97 for benign and 3.9 +/- 1.52 for malignant fractures, p < 0.001). SUV of benign acute and chronic fractures were not statistically significant., Conclusion: Fluorodeoxyglucose positron emission tomography is useful in differentiating benign from malignant compression fractures. Therapy with bone marrow-stimulating agents can mimic malignant involvement.

Objective: The objective was to describe the imaging and histopathologic characteristics of metastatic myxoid liposarcomas., Materials and Methods: This retrospective study was approved by the institutional review board and complied with HIPAA guidelines. The study group comprised 12 patients with metastatic myxoid liposarcoma who underwent MRI, CT, or FDG-PET. The location and imaging characteristics of the metastatic lesions were recorded, and the histopathology of all metastatic lesions was reviewed., Results: There were 23 histologically proven metastases in 12 patients. Based on imaging criteria, there were 41 metastases. The mean time from the diagnosis of primary tumor to the first metastasis was 4.4 years. Sixty-seven percent of patients had bone and soft tissue metastases, 33% had pulmonary metastases, 33% had liver metastases, 25% had intra-abdominal, and 16% retroperitoneal metastases. CT demonstrated well-defined lobulated masses with soft tissue attenuation in all cases, without macroscopic fat component. In cases of osseous metastases, CT showed mixed lytic and sclerotic foci, with bone destruction in advanced cases. MRI demonstrated fluid-like signal intensity with mild heterogeneous enhancement in cases of soft tissue metastases. In osseous metastases, MRI showed avid heterogeneous enhancement. FDG-PET showed no significant FDG uptake for all metastases. MRI was the most useful imaging modality for osseous and soft tissue metastases., Conclusion: Myxoid liposarcomas are soft tissue sarcomas, with a high prevalence of extrapulmonary metastases. The bones and soft tissues were the most common site of involvement, followed by the lungs and liver. MRI was the most sensitive modality in the detection of osseous and soft tissue metastases, and is the recommended modality for the diagnosis and follow-up of bone and soft tissue involvement.

Objective: The objective of our study was to investigate the use of PET in the detection of malignant peripheral nerve sheath tumors (MPNSTs) in patients with neurofibromatosis type 1 (NF1)., Materials and Methods: Forty-five patients with NF1 who underwent whole-body PET for suspected MPNST based on clinical symptoms or radiologic examinations were retrospectively evaluated. Ten patients underwent additional carbon-11 (11C) methionine PET because of equivocal 18F-FDG PET findings or because of a discrepancy between the FDG PET and clinical findings. PET images were evaluated for the distribution and uptake pattern, and the standardized uptake values (SUVs) were obtained. Twenty-seven patients underwent biopsy or surgery of the detected lesions and 18 patients were followed up clinically and with repeat imaging studies., Results: Fifty lesions were identified on FDG PET. There were eight false-positive results and one false-negative on FDG PET. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of FDG PET in detecting MPNSTs in patients with NF1 were 95%, 72%, 71%, 95%, and 82%, respectively. Using 11C methionine PET in combination with FDG PET reduced the number of false-positive results from eight to two, which increased the specificity from 72% to 91%. In five patients, 11C methionine FDG PET contributed additional information about nontarget lesions that influenced treatment planning., Conclusion: FDG PET is a sensitive technique in the detection of MPNSTs in patients with NF1. The addition of 11C methionine PET increases specificity in equivocal cases. PET may improve preoperative tumor staging by detecting metastases or second primary tumors, which often are present in patients with NF1.

Purpose: To retrospectively determine the frequency of posterior and anterior cystic abnormalities at rotator cuff insertion site on the greater tuberosity and to determine their relationship to patient age and rotator cuff disorders., Materials and Methods: Institutional review board approval was given; informed consent was waived. The study was HIPAA compliant. In 238 patients with rotator cuff diagnoses at surgery, preoperative magnetic resonance (MR) imaging studies were reviewed to localize osseous cystic changes as anterior (supraspinatus insertion site) or posterior (infraspinatus insertion site) on the greater tuberosity. If rotator cuff tear was present, tendon retraction and location of partial tear (articular or bursal surface) were recorded. Two radiologists reached conclusions by consensus. Locations of cysts were correlated to surgical cuff diagnoses: no tear, tendinopathy, partial-thickness tear, and complete tear. Prospective interpretations from original MR reports were compared with surgical results. Statistical analyses included one-way analysis of variance, chi(2), Fisher exact, and Student t tests, as well as logistic regression and receiver operating characteristic curve comparison., Results: There were 238 consecutive patients (150 men, 88 women; mean age, 43 years). Cysts were located at or near footprint of cuff tendon and demonstrated fluid or soft-tissue signal intensities. Posterior cysts occurred in 56.7% of shoulders and showed no statistical correlation to age or cuff diagnosis. Anterior cysts occurred in 22.7% of shoulders and were strongly associated with cuff disorders (P<.001). Controlling for cuff disorders, there was no relationship between anterior cysts and age (P>.50). Anterior cysts were more common in partial-thickness articular (48%) than in bursal (13%) tears (P<.001)., Conclusion: Posterior cysts were more common than anterior cysts and showed nearly random distribution among patients, regardless of age and cuff diagnosis. Anterior cysts were closely associated with cuff disorders., ((c) RSNA, 2007.)