SSR white paper: guidelines for utilization and performance of direct MR arthrography

OBJECTIVE

Direct magnetic resonance arthrography (dMRA) is often considered the most accurate imaging modality for the evaluation of intra-articular structures, but utilization and performance vary widely without consensus. The purpose of this white paper is to develop consensus recommendations on behalf of the Society of Skeletal Radiology (SSR) based on published literature and expert opinion.

MATERIALS AND METHODS

The Standards and Guidelines Committee of the SSR identified guidelines for utilization and performance of dMRA as an important topic for study and invited all SSR members with expertise and interest to volunteer for the white paper panel. This panel was tasked with determining an outline, reviewing the relevant literature, preparing a written document summarizing the issues and controversies, and providing recommendations.

RESULTS

Twelve SSR members with expertise in dMRA formed the ad hoc white paper authorship committee. The published literature on dMRA was reviewed and summarized, focusing on clinical indications, technical considerations, safety, imaging protocols, complications, controversies, and gaps in knowledge. Recommendations for the utilization and performance of dMRA in the shoulder, elbow, wrist, hip, knee, and ankle/foot regions were developed in group consensus.

CONCLUSION

Although direct MR arthrography has been previously used for a wide variety of clinical indications, the authorship panel recommends more selective application of this minimally invasive procedure. At present, direct MR arthrography remains an important procedure in the armamentarium of the musculoskeletal radiologist and is especially valuable when conventional MRI is indeterminant or results are discrepant with clinical evaluation.

Utilizing stem cells in reconstructive treatments for sports injuries: An innovative approach

Orthopedic tissue engineering is a rapidly evolving field that holds great promise for the reconstruction and natural repair of bone and joint tissues. Bone loss, fractures, and joint degeneration are common problems that can result from a variety of pathological conditions, and their restoration and replacement are essential not only for functional purposes but also for improving the quality of life for patients. However, current methods rely heavily on artificial materials that can potentially lead to further tissue damage, making tissue engineering a highly attractive alternative. This innovative approach involves the utilization of stem cells (SCs), which are seeded onto a scaffold to form a biological complex. Among these SCs, mesenchymal stem cells (MSCs) extracted from bone marrow and adipose tissue have shown immense potential for bone and joint tissue regeneration. The success of orthopedic tissue engineering is contingent on the careful selection of appropriate scaffolds and inducing molecules, which play a critical role in carrying and supporting cells and inducing their differentiation. This review article comprehensively analyzes the three vital aspects of orthopedic tissue engineering - SCs, scaffolds, and inducing molecules - in order to provide a deeper understanding of this emerging field and its potential for the future of orthopedic medicine.

Increased signal of the fibular collateral ligament of the knee on MRI, clinically significant?

INTRODUCTION

The purpose of this study was to determine the clinical significance of signal hyperintensity in the proximal fibular collateral ligament (FCL) on coronal proton density (PD) fat-saturated (FS) MRI of the knee, a common finding. This study is unique in that it characterizes the FCL of a comprehensive, large cohort of both symptomatic and asymptomatic patients, which to our knowledge represents the first study with such broad inclusion criteria.

METHODS

A large case series was performed analyzing MRI of the knee of 250 patients from July 2021 through September 2021 and retrospectively reviewed. All studies were performed on 3-Tesla MRI scanners with a dedicated knee coil and in accordance with standard institutional knee MRI protocol. Signal in the proximal fibular collateral ligament was assessed on coronal PDFS and axial T2-weighted FS images. Increased signal was classified as none, mild, moderate, or severe. A corresponding chart review of clinic notes was performed to determine the presence or absence of lateral knee pain. An FCL sprain or injury was considered present if the medical record described tenderness on palpation of the lateral knee, positive finding against resistance to the leg (varus stress test) or reverse pivot shift, or any clinical suspicion for lateral complex sprain or posterolateral corner injury.

RESULTS

The majority (74%) of knee MRIs demonstrated the presence of increased signal in the proximal fibular collateral ligament on coronal PD FS images. <5% of these patients had associated clinical findings of fibular collateral ligament and/or lateral supporting structure injury.

DISCUSSION

Although increased signal in the proximal FCL of the knee is a common finding on coronal PDFS images, the majority are not associated with clinical symptoms. Thus, this increased signal is likely not a pathological finding in the absence of clinical findings of fibular collateral ligament sprain/injury. Our study emphasizes the importance of clinical correlation in identifying increased signal in the proximal FCL as pathologic.

The Reliability of 3-T Magnetic Resonance Imaging to Identify Arthroscopic Features of Meniscal Tears and Its Utility to Predict Meniscal Tear Reparability

BACKGROUND

The ability to predict meniscus tear reparability based on preoperative magnetic resonance imaging (MRI) is desirable for postoperative planning; however, the accuracy of predictive methods varies widely within the orthopaedic and radiology literature.

PURPOSE/HYPOTHESIS

The purpose was to determine if the higher resolution offered by 3-T MRI improves the accuracy of predicting reparability compared with previous investigations using 1.5-T MRI. Our hypothesis was that a higher field strength of 3-T MRI would result in improved reliability assessments and predictions of meniscus tear reparability compared with previous studies utilizing a 1.5-T MRI platform.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 2.

METHODS

A total of 44 patients who underwent meniscus repair were matched by age, sex, and body mass index to 43 patients who underwent partial meniscectomy. Overall, 2 orthopaedic surgeons and 2 musculoskeletal radiologists independently and blindly reviewed the preoperative MRI scans for all 87 patients. For each meniscus tear, reviewers evaluated the following criteria: tear pattern, tear length, tear distance from the meniscocapsular junction, tear thickness, and integrity of any inner meniscal fragment. The resultant data were then applied to 5 different approaches for predicting meniscal reparability.

RESULTS

The accuracy for all examined prediction methods was poor, ranging from 55% (3-point method) to 72% (classification tree method) among all reviewers. Interobserver reliability for examined criteria was also poor, with kappa values ranging from 0.07 (inner meniscal fragment status) to 0.40 (tear pattern).

CONCLUSION

MRI continues to be a poor predictor of meniscus tear reparability as assessed by arthroscopic criteria, even when using higher resolution 3-T scanners. Interobserver reliability in this setting can be poor, even among experienced clinicians.

Aggressive osteoblastoma with a secondary aneurysmal bone cyst treated with denosumab

Osteoblastomas and aneurysmal bone cysts (ABC) are rare benign bone tumors that make up about 1%-2% of primary bone malignancies, typically occurring in young patients with a median age of 20 years, most commonly effecting the axial skeleton. ABCs may develop independently as primary lesions, or secondary to other bony lesions including osteoblastomas, chondroblastomas, and giant cell tumors. Treatment of unresectable or extensive osteoblastomas can be challenging. In 2013, the Food and Drug Administration (FDA) approved denosumab for the treatment of giant cell tumors of the bone due to its efficacy in these morbid bony lesions. Various case reports have shown that osteoblastomas can respond to denosumab. Furthermore, numerous ABC case reports have described the efficacy of denosumab in these situations. We herein describe a unique case of a young patient with an aggressive osteoblastoma and secondary ABCs who was successfully treated with denosumab.

Abstract CT221: A phase I study of intratumoral BO-112 and nivolumab for resectable soft tissue sarcoma

Background: BO-112 is a double stranded synthetic RNA formulated with polyethyleneimine. By mimicking a viral infection, it mobilizes the immune system, including activation of dendritic cells, CD8 T-cell infiltration, induction of interferons, and enhancement of immunogenic cell death. Intratumoral (IT) BO-112 has been tested both alone and in combination with anti-PD-1 therapies in a phase I trial (NCT02828098), which showed an overall response rate (ORR) of 11% and disease control rate (DCR) of 46% in patients with multiple tumor types and a tolerable safety profile. While anti-PD1 therapies have shown promise in select subtypes of soft tissue sarcoma (STS), their overall efficacy in STS has been limited. We hypothesize that BO-112, in combination with radiotherapy (RT), may reverse resistance to anti-PD1 therapy in a subset of patients with STS.

Methods: This is an exploratory phase I study of IT BO-112 in combination with nivolumab in patients with STS planning to undergo neoadjuvant RT (NCT04420975) and surgery. BO-112 at a dose of 1 mg will be administered intratumorally on days 1, 8 and 15; nivolumab 240 mg will be administered intravenously on days 8 and 22. Patients will receive 5 fractions of neoadjuvant RT between day 8 and 12, followed by surgical resection between days 26 and 50. Twenty patients with newly diagnosed high grade histologically confirmed STS of the extremity, trunk or retroperitoneum amenable for IT injection will be included. Allowed histological subtypes are undifferentiated pleomorphic sarcoma, myxofibrosarcoma, leiomyosarcoma, dedifferentiated liposarcoma and synovial sarcoma.The primary objective is to explore the safety of BO-112 in combination with nivolumab in patients undergoing preoperative RT. The study includes stopping rules based on the frequency of dose limiting toxicities. As an exploratory single arm pilot study results will be reported using purely descriptive statistics. Tumor and blood specimens collected at baseline, at each IT BO-112 injection, and surgery will allow evaluation of the dynamic changes in tumor immune infiltration, T cell receptor repertoire, and tumor necrosis. These dynamic changes, along with putative biomarkers, such as baseline tumor mutational load, copy number alterations, tumor immune composition, tumor and immune gene expression signatures, and PD-L1 expression, will be related to individual subject tumor responses. The 2-year rate of local recurrence and distant metastasis will also be assessed. This study began accrual in December 2020 and is open.

Citation Format: Anusha Kalbasi, Fritz C. Eilber, Arun Singh, Bartosz Chmielowski, Nicholas Bernthal, Brooke Crawford, Joseph G. Crompton, Varand Ghazikhanian, Leanne Seeger, Kambiz Motamedi, Michael L. Douek, Carol Felix, Vincent Basehart, Helena Escuin-Ordinas, Marisol Quintero, Sonia Macia. A phase I study of intratumoral BO-112 and nivolumab for resectable soft tissue sarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT221.

ACR Appropriateness Criteria® Primary Bone Tumors

Although primary bone tumors are relatively uncommon, appropriate imaging evaluation is essential when they are suspected or incidentally detected. In almost all cases, radiographs are the most appropriate initial imaging study for screening and characterization of primary bone tumors. Radiographs often provide sufficient information for diagnosis and to guide the treating clinician. However, when conventional radiographs alone are inadequate, they still often guide the selection of the most appropriate next step for advanced imaging. MRI and CT are typically the most appropriate next step. MRI provides excellent soft-tissue contrast allowing for evaluation of the tissue composition (such as fat, hemorrhage, fluid levels) and anatomic extent of bone tumors. CT provides complementary information, with its ability to detect subtle matrix mineralization or periosteal reaction that may not be seen on radiographs or MRI. This publication focuses on six common variants to guide diagnosis and management of primary bone tumors. In addition to conventional radiographs, appropriate use of MRI, CT, PET/CT, bone scan, and ultrasound are discussed. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Increased signal in the proximal patellar tendon: normal or pathologic?

OBJECTIVE

To determine the clinical significance of T2 signal hyperintensity in the proximal patellar tendon seen on MRI of the knee.

MATERIALS AND METHODS

MRIs of 100 patients who underwent MRI of the knee between 1 May 2018 and 15 July 2018 were retrospectively evaluated. All examinations were performed on 3-Tesla MRI scanners with a dedicated knee coil and in accordance with our institution's standard knee MRI protocol. The presence of increased T2 signal was assessed on both sagittal and axial T2-weighted fat-saturated images. The amount of increased signal in the proximal patellar tendon on T2-weighted images was characterized as: none, mild, moderate, or severe. A corresponding chart review of the referring physicians' notes was performed to determine the presence of clinical symptoms of patellar tendinopathy. Patellar tendinopathy was considered present if the clinical notes described tenderness on palpation of the inferior patellar pole, infrapatellar tenderness, or patellar tendinosis/tendinitis.

RESULTS

The majority (66%) of knee MRIs demonstrated the presence of increased T2 signal in the proximal patellar tendon. Only 4.5% of these patients had associated clinical findings of patellar tendinopathy.

CONCLUSION

Although increased T2 signal in the proximal patellar tendon is a common finding, only in rare cases are there associated clinical symptoms. Thus, increased T2 signal in the proximal patellar tendon may not be a pathological finding in the absence of clinical findings of patellar tendinopathy.

Pathologic discordance in sarcomas: Prospective comparison of external and sarcoma center pathologic diagnosis

11020

Background: With more than 80 different histologic subtypes, sarcomas are a unique pathologic challenge. As therapeutic decisions have become histology-specific, obtaining an accurate pathologic diagnosis is critical in guiding treatment decisions. The aim of this study is to determine the discordance between the diagnosis rendered by an external non-specialized pathologist and pathologic re-review by a specialized sarcoma pathologist at a high-volume sarcoma center. Methods: Patients who presented at the UCLA Multidisciplinary Sarcoma Conference (MSC) in 2017 that had a pathologic diagnosis from an outside facility were included in this study. All specimens underwent pathologic re-review at UCLA by an experienced sarcoma pathologist. The pathology was classified as concordant (identical diagnoses), minor discordance (difference with minor impact on prognosis/therapy) and major discordance (difference with significant impact on prognosis/therapy). Results: 1350 patients were presented at the UCLA MSC in 2017. Of the 635 new patients, 196 presented with an outside pathologic diagnosis and underwent pathologic re-review at UCLA. 44% (n = 87) were concordant, 22% (n = 43) had minor discordance, and 34% (n = 66) had major discordance. Major discordance included substantial discrepancies in histologic subtype (n = 24, 36%), benign/malignant mismatch (n = 23, 35%), diagnostic from non-diagnostic (n = 12, 18%) and major grading discrepancy (n = 7, 11%). Major discordance was most often seen in biopsies [needle (n = 27, 32%), incisional (n = 30, 44%)] as compared to resection (n = 9, 21%). Conclusions: 56% of external non-specialized sarcoma pathologic diagnoses were discordant from specialized sarcoma pathologist review, 34% of which were major discordances. Pathologic re-review of a presumed sarcoma by a specialized sarcoma pathologist is critical for both patient care and investigational studies. [Table: see text]

ACR Appropriateness Criteria® Shoulder Pain-Traumatic

Traumatic shoulder pain is pain directly attributed to a traumatic event, either acute or chronic. This pain may be the result of either fracture (the clavicle, scapula, or proximal humerus) or soft-tissue injury (most commonly of the rotator cuff, acromioclavicular ligaments, or labroligamentous complex). Imaging assessment of traumatic shoulder pain begins with conventional radiography and, depending on physical examination findings, will require MRI or MR arthrography for assessment of soft-tissue injuries and CT for delineation of fracture planes. Ultrasound excels in assessment of rotator cuff injuries but has limited usefulness for assessment of the deep soft-tissues. CT angiography and conventional arteriography are helpful for assessment of vascular injury, and bone scintigraphy can be used in assessment of complex regional pain syndrome after traumatic shoulder injury. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Intraneural Hemangioma: Case Report of a Rare Tibial Nerve Lesion

An intraneural hemangioma is a rare, benign mesodermal lesion. We present a case of a three-year-old female with the inability to straighten her right knee and fullness over the right popliteal fossa for one year. Magnetic resonance imaging (MRI) demonstrated a T2 hyperintense lesion of the popliteal fossa, within the tibial nerve. The patient underwent an uncomplicated right knee excisional biopsy, which confirmed the diagnosis of an intraneural hemangioma. Although rare, an intraneural hemangioma should be considered in the differential diagnosis of a soft tissue lesion located in the expected course of a peripheral nerve.

Efficacy of intraarticular corticosteroid hip injections for osteoarthritis and subsequent surgery

OBJECTIVE

Our study aimed to determine the duration of pain relief from intraarticular hip corticosteroid injections and identify patient predictive factors on injection response. We also sought to determine the subsequent rate of hip surgery and whether severity of hip osteoarthritis or injection response correlated with the decision to undergo surgery.

MATERIALS AND METHODS

All intraarticular hip steroid injections performed for osteoarthritis under fluoroscopic guidance at a single institution between January 2010 to December 2012 were retrospectively reviewed. Response was divided into three groups: no relief, immediate (≤ 2 weeks of pain relief), and continued (> 2 weeks of pain relief). Presence of hip surgery for osteoarthritis performed within 2 years following injection was obtained. Correlation between patient characteristics with injection outcome and hip surgery was analyzed.

RESULTS

Of 78 patients, a total of 82 injections were analyzed. For injections, 19.5% (16/82) showed no response, 47.6% (39/82) showed immediate response, and 32.9% (27/82) showed continued response. There was no significant correlation between injection outcome with age, Tönnis grade, BMI, or duration of symptoms. In total, 48.7% had hip surgery within 2 years after initial injection. There was a significant association between Tönnis grade and surgery, with higher Tönnis grades correlating with decision to undergo surgery (p = 0.002).

CONCLUSIONS

Gender, age, BMI, duration of symptoms, and radiographic severity of disease do not predict injection response. Due to high surgical rates and poor response, intraarticular hip steroid injections may be less effective in the long term, and surgical management may be considered earlier.

Relationship of ACL Injury and Posterior Tibial Slope With Patient Age, Sex, and Race

BACKGROUND

Posterior tibial slope (PTS) has been proposed as a potential risk factor for anterior cruciate ligament (ACL) injury; however, studies that have examined this relationship have provided inconclusive and sometimes contradictory results. Further characterization of this relationship may enable the medical community to identify individuals at greater risk for ACL injury and possibly characterize an anatomic target during surgical reconstruction.

PURPOSE

The primary goal was to investigate the relationship between PTS and ACL injury. The secondary goal was to determine whether there are any patient factors, such as age, race, or sex, that correlate with ACL injury and PTS.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Medical records of 221 patients who underwent magnetic resonance imaging (MRI) of the knee between January 2003 and December 2009 were reviewed. Patients were separated into 2 groups: a study group of those subjects who had undergone surgery for ACL injury (n = 107) and a control group of patients diagnosed with patellofemoral syndrome (n = 114). Demographic data were collected, and MRI images from both groups were analyzed using imaging software to obtain medial and lateral tibial slope measurements. Data were then analyzed using analysis of variance (ANOVA) comparison and a multivariable regression model to determine which, if any, patient factors were related to probability of having an ACL injury.

RESULTS

ANOVA comparison demonstrated that the study group had significantly greater values for lateral PTS (6° ± 4°; P < .001) and medial PTS (7° ± 4°; P = .002) compared with controls (5° ± 3° and 5° ± 4°, respectively). After stepwise elimination of nonsignificant variables, the final multivariable logistic regression model determined that age (odds ratio [OR], 0.94; P < .001) and lateral PTS (OR, 1.12; P = .002) had statistically significant relationships with ACL injury. Medial PTS, race, and sex were not demonstrated to be significant predictors of ACL injury in this final model.

CONCLUSION

This study demonstrates a relationship between increased lateral PTS and ACL injury, which corroborates the findings of previously published studies. The findings presented in this article may help identify patients who are at greater risk of ACL injury and could potentially benefit from treatments aimed at modification of PTS.

Comprehensive appraisal of magnetic resonance imaging findings in sustained rheumatoid arthritis remission: a substudy

OBJECTIVE

To evaluate the effect of sustained American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) Boolean remission on residual joint inflammation assessed by magnetic resonance imaging (MRI) and to secondarily evaluate other clinical definitions of remission, within an early seropositive rheumatoid arthritis (RA) cohort.

METHODS

A subcohort of 118 RA patients was enrolled from patients who completed the 2-year, double-blind randomized Treatment of Early Aggressive Rheumatoid Arthritis (TEAR) trial. Patients received a single contrast-enhanced 1.5T MRI of their most involved wrist. Two readers scored MRIs for synovitis, osteitis, tenosynovitis, and erosions. Clinical assessments were performed every 3 months during the trial and at time of MRI.

RESULTS

The subcohort was 92% seropositive with mean age 51 years, duration 4.1 months, and Disease Activity Score in 28 joints using the erythrocyte sedimentation rate 5.8 at TEAR entry. Total MRI inflammatory scores (tenosynovitis + synovitis + osteitis) were lower among patients in clinical remission. Lower MRI scores were correlated with longer duration of Clinical Disease Activity Index (CDAI) remission (ρ = 0.22, P = 0.03). At the time of MRI, 89 patients had no wrist pain/tenderness/swelling; however, all 118 patients had MRI evidence of residual joint inflammation after 2 years. No statistically significant differences in damage or MRI inflammatory scores were observed across treatment groups.

CONCLUSION

This is the first detailed appraisal describing the relationship between clinical remission cut points and MRI inflammatory scores within an RA randomized controlled trial. The most stringent remission criteria (2011 ACR/EULAR and CDAI) best differentiate the total MRI inflammatory scores. These results document that 2 years of triple therapy or tumor necrosis factor plus methotrexate treatment in early RA does not eliminate MRI evidence of joint inflammation.

Reducing Unnecessary Portable Pelvic Radiographs in Trauma Patients: A Resident-Driven Quality Improvement Initiative

Quality improvement is increasingly important in the changing health care climate. We aim to establish a methodology and identify critical factors leading to successful implementation of a resident-led radiology quality improvement intervention at the institutional level. Under guidance of faculty mentors, the first-year radiology residents developed a quality improvement initiative to decrease unnecessary STAT pelvic radiographs (PXRs) in hemodynamically stable trauma patients who would additionally receive STAT pelvic CT scans. Development and implementation of this initiative required multiple steps, including: establishing resident and faculty leadership, gathering evidence from published literature, cultivating multidisciplinary support, and developing and implementing an institution-wide ordering algorithm. A visual aid and brief questionnaire were distributed to clinicians for use during treatment of trauma cases to ensure sustainability of the initiative. At multiple time points, pre- and post-intervention, residents performed a retrospective chart review to evaluate changes in imaging-ordering trends for trauma patients. Chart review showed a decline in the number of PXRs for hemodynamically stable trauma patients, as recommended in the ordering algorithm: 78% of trauma patients received both a PXR and a pelvic CT scan in the first 24 hours of the initiative, compared with 26% at 1 month; 24% at 6 months; and 18% at 10 to 12 months postintervention. The resident-led radiology quality improvement initiative created a shift in ordering culture at an institutional level. Development and implementation of this algorithm exemplified the impact of a multidisciplinary collaborative effort involving multiple departments and multiple levels of the medical hierarchy.

Osteochondral lesions in pediatric and adolescent patients

Osteochondral lesions are acquired, potentially reversible injuries of the subchondral bone with or without associated articular cartilage involvement. Injury results in delamination and potential sequestration of the affected bone. Although an association with mechanical and traumatic factors has been established, the etiology remains poorly understood. These lesions commonly occur in the knee; articular surfaces of the elbow, ankle, hip, and shoulder are also affected. Osteochondral lesions are relatively common in children and adolescents, and the incidence is increasing. Prognosis of these lesions depends on stability, location, and size of the lesion.Imaging has an essential role in the diagnosis, staging, and management of osteochondral lesions. Many of these lesions are first diagnosed by plain film. MRI adds value by identifying unstable lesions that require surgical intervention. This review focuses on the clinical and imaging features of osteochondral lesions of the knee, elbow, and ankle. Imaging criteria for staging and management are also reviewed.

Subcutaneous panniculitis-like T-cell lymphoma: MRI features and literature review

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) represents a rare subclassification of peripheral T-cell lymphoma (PTCL). We present a case of a 21-year-old female who presented with a 1-month history of pain in the left buttock and hip, tender left inguinal lymph nodes, fevers, and night sweats. Percutaneous core needle biopsy was diagnostic for SPTCL with CD8+ cells positive for cytotoxic granules. Magnetic resonance imaging (MRI) features of SPTCL with a review of the literature are discussed.

Benign bone tumors

A solid knowledge of underlying histopathology of benign bone tumors aids in differential diagnoses of these tumors. Important factors in diagnosis of a bone tumor include patient age and gender; the bone involved; the location of the tumor along, within, or on the bone; lesion margin; matrix proliferation; and periosteal reaction. This article provides a review of the origin of the tumor matrix and its influence on the imaging properties of these tumors.

Can the reparability of meniscal tears be predicted with magnetic resonance imaging?

BACKGROUND

Historically, magnetic resonance imaging (MRI) has been very useful in diagnosing meniscal tears but not as valuable in predicting whether a meniscal tear is reparable. Given that several recent studies suggested that MRI can be used to predict tear reparability, the topic has resurfaced as a controversy in the orthopaedic and radiology literatures.

HYPOTHESIS

Experienced musculoskeletal radiologists can use MRI to predict the reparability of meniscal tears with good to excellent accuracy using the same arthroscopic criteria used by surgeons intraoperatively.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 3.

METHODS

Fifty-eight patients with meniscal tears treated with repair were matched by age and sex with 61 patients with tears treated with meniscectomy. Two senior musculoskeletal radiologists independently and blindly reviewed preoperative MRI of these 119 meniscal tears. Using established arthroscopic criteria, the radiologists were asked to grade each tear 0 to 4, with 1 point for each of the following: a tear larger than 10 mm, within 3 mm of the meniscosynovial junction, greater than 50% thickness, and with an intact inner meniscal fragment. Only a tear with a score of 4 would be predicted to be reparable.

RESULTS

The 2 radiologists' ability to correctly estimate reparability was poor, with 58.0% and 62.7% correct predictions (κ = 0.155 and 0.250, respectively). Interrater reliability assessment showed that the raters agreed on a score of 4 (reparable) versus <4 (not reparable) 73.7% of the time (κ = 0.434) but came to identical scores only 38.1% of the time (κ = 0.156). Determining the status of the inner fragment was the most predictive individual criterion and the only one to reach statistical significance (χ(2) = 14.9, P <.001).

CONCLUSION

Magnetic resonance imaging is not an effective or efficient predictor of reparability of meniscal tears with the current arthroscopic criteria.

Thermal ablation of osteoid osteoma: overview and step-by-step guide

Osteoid osteoma is a small, benign but painful lesion with specific clinical and imaging characteristics. Computed tomography is the imaging modality of choice for visualization of the nidus and for treatment planning. Complete surgical excision of the nidus is curative, providing symptomatic relief, and is the traditionally preferred treatment. However, surgery has disadvantages, including the difficulty of locating the lesion intraoperatively, the need for prolonged hospitalization, and the possibility of postoperative complications ranging from an unsatisfactory cosmetic result to a fracture. Percutaneous radiofrequency (RF) ablation, which involves the use of thermal coagulation to induce necrosis in the lesion, is a minimally invasive alternative to surgical treatment of osteoid osteoma. With reported success rates approaching 90%, RF ablation should be considered among the primary options available for treating this condition.

Cam-type femoral-acetabular impingement: is the alpha angle the best MR arthrography has to offer?

INTRODUCTION

In our institutional experience, determination of the alpha (alpha) angle at MR arthrography as an indicator of the likelihood of cam-type femoroacetabular impingement (FAI) is fraught with inconsistency. The aims of this study were to quantify the degree of variability in and calculate the diagnostic accuracy of the alpha angle in suggesting a diagnosis of cam impingement, to determine the accuracy of a positive clinical impingement test, and to suggest alternative MR arthrographic measures of femoral head-neck overgrowth and determine their diagnostic utilities.

MATERIALS AND METHODS

We carried out a retrospective analysis of MR arthrographic studies performed during a 4-year period, combined with chart analysis, which allowed identification of 78 patients in whom surgical correlation was also available. The status of a preoperative clinical impingement test was also noted. Patients were designated as having cam-type FAI (Group A, n = 39) if intra-operative femoral head-neck junction bony osteochondroplasty/arthoscopic femoral debridement was performed. Group B (n = 39) acted as controls. Three radiologists independently and blindly performed a series of measurements (alpha angle and two newly proposed measurements) in each patient on two separate occasions. An alpha angle of greater than 55 degrees was considered indicative of the presence of cam-type FAI.

RESULTS

Performance values for alpha angle measurement were poor for each observer. There was considerable (up to 30% of the mean value) intra-observer variability between the first and second alpha angle measurements for each subject. Binary logistic regression analysis confirmed that the alpha angle is of no value in predicting the presence or absence of cam-FAI. A statistically significant difference existed between Groups A and B with regard to the newly proposed anterior femoral distance (AFD; p = 0.004). Using an AFD value of 3.60 mm or greater as being indicative of the presence of cam-FAI yields a 0.67 performance measure (95% confidence interval 0.55-0.79). The second proposed parameter (femoral neck ratio) was of no value in suggesting the presence or absence of this condition. The sensitivity, specificity, and positive and negative predictive values of the clinical impingement test were 76.9%, 87.2%, 85.7% and 79.1% respectively.

CONCLUSIONS

Femoral alpha angle measurement is associated with considerable variability. This index performed poorly in our patient population and was statistically of no value in suggesting the presence or absence of cam-FAI. One of our proposed measures, the AFD, outperformed the alpha angle, though to an insufficient degree to suggest its routine incorporation into clinical practice. Our experience suggests that the clinical impingement test remains the most reliable predictor of the presence of this condition.

Tophaceous gout of the first costochondral junction in a heart transplant patient

We report the case of a 49-year-old man with a 10-year history of gout, who presented with a painful left first costochondral junction mass. A computed tomography (CT)-guided biopsy of the mass revealed foreign body giant cell reaction and crystalline deposition consistent with tophaceous gout.

Three-dimensional computed tomography of the hip in the assessment of femoroacetabular impingement

Femoroacetabular impingement secondary to the cam effect is thought to be associated with an insufficient anterior concavity in the sagittal/axial plane of the femoral head-neck junction. Using three-dimensional computed tomography the anterior and posterior concavity of the femoral head-neck junction was assessed in 36 painful non-dysplastic hips (30 patients). The mean age of the symptomatic hips was 40.7 with 13 females and 17 males. Eighteen out of the 36 hips had a pistol grip deformity. Magnetic resonance gadolinium arthrography was performed to assess for labral and cartilage lesions. Alpha and beta angles measuring the anterior and posterior femoral head-neck junction concavities were also determined in 20 asymptomatic hips (12 patients; mean age 37, 5 females and 7 males) using three-dimensional computed tomography. The mean alpha angle for the symptomatic and the control group were: 66.4 versus 43.8 (p=0.001), and for the beta angle 40.2 versus 43.8 (p=0.011), respectively. All but one of the symptomatic hips had a labral tear with 61% of these hips having associated cartilage damage. Three-dimensional computed tomography represents an accurate tool to quantify the femoral head-neck concavity providing a non-invasive assessment of hips at risk of femoroacetabular impingement.

Three-dimensional computed tomography of the hip in the assessment of femoroacetabular impingement

Femoroacetabular impingement secondary to the cam effect is thought to be associated with an insufficient anterior concavity in the sagittal/axial plane of the femoral head-neck junction. Using three-dimensional computed tomography the anterior and posterior concavity of the femoral head-neck junction was assessed in 36 painful non-dysplastic hips (30 patients). The mean age of the symptomatic hips was 40.7 with 13 females and 17 males. Eighteen out of the 36 hips had a pistol grip deformity. Magnetic resonance gadolinium arthrography was performed to assess for labral and cartilage lesions. Alpha and beta angles measuring the anterior and posterior femoral head-neck junction concavities were also determined in 20 asymptomatic hips (12 patients; mean age 37, 5 females and 7 males) using three-dimensional computed tomography. The mean alpha angle for the symptomatic and the control group were: 66.4 versus 43.8 (p=0.001), and for the beta angle 40.2 versus 43.8 (p=0.011), respectively. All but one of the symptomatic hips had a labral tear with 61% of these hips having associated cartilage damage. Three-dimensional computed tomography represents an accurate tool to quantify the femoral head-neck concavity providing a non-invasive assessment of hips at risk of femoroacetabular impingement.

Imaging of postoperative knee extensor mechanism

Disorders of the anterior knee are common and include patellofemoral syndrome, patella instability, patella fracture, and patellar and quadriceps tendon ruptures. Depending on the operative procedure performed, the post-operative imaging appearance of these knees may be confusing. It is crucial for the radiologist to be familiar with the procedures performed in order to recognize the postoperative findings. Radiologists must be able to interpret hardware (anchors, screw and wires) and disruptions in soft tissue planes that may persist with these types of procedures.

Villonodular synovitis (PVNS) of the spine

OBJECTIVE

To describe the imaging features of spinal pigmented villonodular synovitis (PVNS).

DESIGN AND PATIENTS

We retrospectively reviewed 15 cases of pathologically proven spinal PVNS. Patient demographics and clinical presentation were reviewed. Radiologic studies were evaluated by consensus of two musculoskeletal radiologists for spinal location, spinal segments affected, lesion center, detection of facet origin and intrinsic characteristics on radiography (n=11), myelography (n=7), CT (n=6) and MR imaging (n=6).

RESULTS

Women (64%) were more commonly affected than men (36%) with an average age of 28 years. Clinical symptoms were pain (45%), neurologic (9%) or both (36%). Lesions most frequently affected the cervical spine (53%) followed by the thoracic (27%) and lumbar regions (20%). The majority of lesions (93%) were centered in the posterior elements with frequent involvement of the pedicle (67%), neural foramina (73%), lamina (67%) and facets (93%). No lesions showed calcification. Determination of a facet origin by imaging was dependent on imaging modality and lesion size. A facet origin could be determined in 45% of cases by radiography vs 67% of patients by CT (n=6) and MR (n=6). Large lesions (greater than 3 cm in at least one dimension) obscured the facet origin in all cases with CT and/or MR imaging (44%,n=4). Small lesions (less than 3 cm in any dimension) demonstrated an obvious facet origin in all cases by CT and/or MR imaging (56%,n=5). Low-to-intermediate signal intensity was seen in all cases on T2-weighted MR images resulting from hemosiderin deposition with "blooming effect" in one case with gradient echo MR images.

CONCLUSIONS

PVNS of the spine is rare. Large lesions obscure the facet origin and simulate an aggressive intraosseous neoplasm. Patient age, a solitary noncystic lesion centered in the posterior elements, lack of mineralization and low-to-intermediate signal intensity on all MR pulse sequences may suggest the diagnosis in these cases. Small lesions demonstrate a facet origin on CT or MR imaging. This limits differential considerations to synovial-based lesions and additional features of a solitary focus, lack of underlying disease or systemic arthropathy, no calcification as well as low-to-intermediate signal intensity on all MR images should allow spinal PVNS to be suggested as the likely diagnosis.

Imaging of the Lumbar Spine Neoplasms

The most common lumbar spine tumors are metastatic disease, myeloma, and hemangioma. Primary osseous lesions of the lumbar spine are unusual. When encountered, they often exhibit characteristic imaging properties, aiding the radiologist to provide a short list of differential diagnoses. We provide a discussion of imaging appearance of lumbar spine neoplasms. Emphasis of this review is on osseous lesions. Few common neurogenic intradural, extraaxial lesions are also discussed.

Synovial-type giant cell tumors of the vertebral column: a clinicopathologic study of 15 cases, with a review of the literature and discussion of the differential diagnosis

Synovial and tenosynovial giant cell tumors only rarely arise in close proximity to the axial skeleton; to date, fewer than 30 examples have been reported in the English-language medical literature. In this report we describe the clinical, radiologic, histopathologic, and immunohistochemical findings in 15 cases retrieved from our files. The study group comprised 7 males and 8 females, ranging in age from 17 to 44 years (mean age, 32 years). The tumors involved the cervical (n = 11), thoracic (n = 1), lumbar (n = 2), and sacrococcygeal (n = 1) regions and ranged in size from 1.0 to 6.0 cm in greatest dimension (median size, 3 cm). Symptoms were present for 2 months to at least 2 years, with the most common complaint being pain localized to the spinal region (n = 12). Ten patients also had radicular symptoms. Radiologic studies, available for 11 cases, usually demonstrated a mass involving the posterior aspect of adjoining vertebrae. Bony abnormalities (including scalloping, erosion, and destruction), facet joint and soft tissue involvement, and extradural extension were typically present. Histologically, all tumors contained a proliferation of epithelioid (histiocytoid) cells, admixed with varying numbers of osteoclast-like giant cells, siderophages, xanthoma cells, lymphocytes, and some spindled fibroblast-like cells. Only 1 tumor had the classic villiform architecture of pigmented villonodular synovitis. The remaining 14 tumors had a nodular appearance with varying amounts of collagen. Seven of these had definite histological evidence of infiltrative growth, and 6 had some features that warranted concern for possible infiltration. Only 1 tumor had findings fully compatible with a localized synovial-type giant cell tumor/nodular (teno)synovitis. All tumors had mitotic activity, with mitotic counts ranging from 1 to 21 mitotic figures per 50 high-power fields (HPFs) (mean mitotic count, 5 mitotic figures/50 HPFs). Immunohistochemistry was performed on 5 tumors, and immunoreactivity was present for CD68, CD163, and vimentin. Limited immunoreactivity for muscle actin (HUC1-1) was also noted. Follow-up information was available for 9 of the 15 patients (60%). Five patients had no evidence of recurrent or persistent disease 4 months to 9 years after undergoing either a local excision with gross total tumor removal (with or without irradiation) or a wide en bloc resection. Four patients had persistent disease after undergoing either an incomplete resection or biopsy with spinal fusion procedure. All 4 of these patients had additional surgical intervention (accompanied by irradiation in 2 instances), but only one was known to be disease-free at last follow-up (10 years after gross total tumor removal). No patient has experienced a metastasis or died of disease. The best predictor of outcome was gross total tumor removal at the surgical outset.

From the archives of the AFIP. Radiologic spectrum of Paget disease of bone and its complications with pathologic correlation

Paget disease of bone is a common disorder affecting approximately 3%-4% of the population over 40 years of age. The pathologic abnormality in Paget disease is excessive and abnormal remodeling of bone. Three pathologic phases have been described: the lytic phase (incipient-active), in which osteoclasts predominate; the mixed phase (active), in which osteoblasts cause repair superimposed on the resorption; and the blastic phase (late-inactive) in which osteoblasts predominate. Radiographic appearance of Paget disease reflects these pathologic changes and is often characteristic. Initially, there is osteolysis, particularly affecting the skull (osteoporosis circumscripta) and subchondral long bones, with subsequent development of trabecular and cortical thickening and enlargement of bone in the mixed phase of the disease. Finally, areas of sclerosis may develop in the blastic phase. Frequent sites of involvement include the skull (25%-65% of cases), spine (30%-75%), pelvis (30%-75%), and proximal long bones (25%-30%). Bone scintigraphy typically demonstrates marked increased uptake of radionuclide in all phases of Paget disease. Computed tomography and magnetic resonance imaging often show changes similar to those seen radiographically in noncomplicated Paget disease with maintenance of yellow marrow. Complications of Paget disease include the effects of osseous weakening (deformity and fracture), arthritis, neurologic symptoms, and neoplastic involvement. Sarcomatous transformation is the most feared complication, occurring in approximately 1% of cases, and is seen on images as focal bone destruction extending through the cortex with an associated soft-tissue mass. Recognition of the radiologic spectrum of the appearances of Paget disease usually allows prospective diagnosis and differentiation of its associated complications, which helps guide therapy and improve patient management.

Cricoid cartilage necrosis after arytenoidectomy in a previously irradiated larynx

Several open and endoscopic surgical techniques are available to provide an adequate airway for patients with bilateral vocal cord paralysis. Transoral laser arytenoidectomy has repeatedly been reported to be a reliable and effective minimally invasive procedure for airway restoration. To our knowledge, there have been no previous reports of serious complications, other than poor vocal results, aspiration, and failed decannulation in individual patients, that have resulted from this intervention. We report a case in which arytenoidectomy led to severe complications and death. Prior irradiation is suspected to be a causative factor. To prevent such an outcome, we believe that operative settings should be chosen that avoid deep thermal injury of the laryngeal framework.