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.

VIDEO: Dynamic Ultrasound for Snapping Hip Syndrome.

OBJECTIVE. The purpose of this video article is to review the dynamic sonographic assessment of snapping hip syndrome. The video focuses on the extraarticular forms of snapping hip and discusses their possible causes, ultrasound features, and treatment options. The dynamic sonographic technique for evaluating snapping hip syndrome is shown with live scanning videos. CONCLUSION. Dynamic ultrasound is well suited for the assessment of snapping hip syndrome and is essential for confirming the clinical diagnosis of the condition.

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.

Is Core Needle Biopsy Reliable in Differentiating Between Aggressive Benign and Malignant Radiolucent Bone Tumors?

BACKGROUND: Although there is widespread acceptance of core needle biopsy (CNB) for diagnosing solid tumors, there is reluctance by some clinicians to use CNB for aneurysmal bone cysts (ABCs) as a result of concerns of safety (bleeding, nerve injury, fracture, readmission, or infection) and reliability, particularly to rule out malignant diagnoses like telangiectatic osteosarcoma. This is especially true when CNB tissue is sent from an outside hospital, where the technique used to obtain the tissue may be spurious. QUESTIONS/PURPOSES: (1) Is CNB effective (provided adequate information to indicate appropriate surgical treatment without further open biopsy) as an initial diagnostic test for ABC? (2) Is CNB accurate (pathology consistent with the subsequent definitive surgical pathologic diagnosis) in differentiating between benign lesions such as primary or secondary ABCs and malignant radiolucent lesions such as telangiectatic osteosarcoma? (3) What are the complications of CNB? (4) Is there any difference in the effectiveness or accuracy of CNB performed at outside institutions when compared with a referral center? METHODS: A retrospective study of our musculoskeletal tumor board pathology database (1990-2016) was performed using search criteria "aneurysmal bone cyst" or "telangiectatic osteosarcoma." Only patients undergoing a CNB who proceeded to definitive surgical resection with final pathology were included. Excluding outside CNBs, CNB was performed after presentation at a musculoskeletal tumor board as a result of atypical features on imaging or history concerning for malignancy. Outside CNB tissue was reviewed by our pathologists. If there was sufficient tissue for diagnosis, the patient proceeded to definitive surgery. If not, the patient underwent open biopsy. CNB diagnosis, open biopsy results, and open surgical resection pathology were reviewed. Complications, including bleeding, infection, nerve injury, readmission, or fracture, between the CNB and definitive open surgical procedure (mean 1.6 months) were documented. CNBs were considered "effective" if they yielded pathology considered sufficient to proceed with appropriate definitive surgery without additional open biopsy. CNBs were considered "accurate" if they were effective and yielded a pathologic diagnosis that matched the subsequent definitive surgical pathology. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of obtaining a malignant diagnosis using CNB were also calculated. RESULTS: A total of 81% (59 of 73) of CNBs were effective. Ninety-three percent (55 of 59) of CNBs were classified as accurate. Diagnostic CNBs had a sensitivity and specificity of 89% (eight of nine) and 100% (51 of 51), respectively. The PPV was 1.00 and the NPV was 0.82. There were no complications. With the numbers available, there was no difference in efficacy (90% [37 of 41 versus 14 of 15]; odds ratio, 0.97 [95% confidence interval {CI}, 0.41-2.27], p = 0.94) or accuracy (92% [34 of 37 versus 13 of 14]; odds ratio, 0.87 [95% CI, 0.08-9.16], p = 0.91) between CNBs performed in house and those referred from outside. CONCLUSIONS: These data suggest that CNBs are useful as an initial diagnostic test for ABC and telangiectatic osteosarcoma. Tissue from outside CNBs can be read reliably without repeat biopsy. If confirmed by other institutions, CNB may be considered a reasonable approach to the diagnosis of aggressive, radiolucent lesions of bone. LEVEL OF EVIDENCE: Level III, diagnostic study.

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.

Percutaneous Image-Guided Musculoskeletal Tumor Treatments.

OBJECTIVE: The purpose of this article is to review the current guidelines and recommendations for percutaneous image-guided treatment of musculoskeletal tumors. CONCLUSION: With the ongoing technologic advances, it is essential that the musculoskeletal interventionalist is familiar with the current tools and techniques available for the treatment of soft-tissue and bone tumors. Fortunately, many of these tools are readily available in a standard interventional radiology department and can be easily applied to the musculoskeletal system.

MR Imaging and US of the Wrist Tendons.

The tendons of the wrist are commonly symptomatic. They can be injured, infected, or inflamed. Magnetic resonance imaging and ultrasonography are useful tools for evaluating the wrist. Pathologic conditions of the wrist tendons include de Quervain tenosynovitis, extensor carpi ulnaris tendinopathy, rheumatoid tenosynovitis, infectious synovitis, tendon tears, hydroxyapatite deposition disease, intersection syndrome, tenosynovial giant cell tumor, and fibroma of the tendon sheath. In this article, we review the normal appearance of the wrist tendons, discuss relevant anatomy, and give an overview of common pathologic conditions affecting the wrist tendons. Online supplemental material is available for this article. ©RSNA, 2016.

Image-guided percutaneous core needle biopsy of musculoskeletal tumors in children.

The use of image-guided percutaneous core needle biopsy (PCNB) to obtain tissue diagnosis of musculoskeletal lesions has become the standard of care in adult patients with a success rate of over 80%. Previous reports indicate a similar success rate in diagnosing pediatric solid tumors. In this large study, we analyzed >10 years of data in which PCNB was used for tissue diagnosis of musculoskeletal lesions in children; we evaluated the histopathologic accuracy, anesthetic requirements, and complications of these procedures. In 122 children, tissue diagnosis was successfully obtained in 82% of cases, and there were 0 complications associated with the procedure. There was a significantly higher PCNB diagnostic success rate in malignant lesions (93%). These data suggest that the use of PCNB is a safe and effective means of diagnosing musculoskeletal lesions in children.

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.

Success rates for computed tomography-guided musculoskeletal biopsies performed using a low-dose technique.

OBJECTIVE: To evaluate the success rate of a low-dose (50% mAs reduction) computed tomography (CT) biopsy technique. This protocol was adopted based on other successful reduced-CT radiation dose protocols in our department, which were implemented in conjunction with quality improvement projects. MATERIALS AND METHODS: The technique included a scout view and initial localizing scan with standard dose. Additional scans obtained for further guidance or needle adjustment were acquired by reducing the tube current-time product (mAs) by 50%. The radiology billing data were searched for CT-guided musculoskeletal procedures performed over a period of 8 months following the initial implementation of the protocol. These were reviewed for the type of procedure and compliance with the implemented protocol. The compliant CT-guided biopsy cases were then retrospectively reviewed for patient demographics, tumor pathology, and lesion size. Pathology results were compared to the ultimate diagnoses and were categorized as diagnostic, accurate, or successful. RESULTS: Of 92 CT-guided procedures performed during this period, two were excluded as they were not biopsies (one joint injection and one drainage), 19 were excluded due to non-compliance (operators neglected to follow the protocol), and four were excluded due to lack of available follow-up in our electronic medical records. A total of 67 compliant biopsies were performed in 63 patients (two had two biopsies, and one had three biopsies). There were 32 males and 31 females with an average age of 50 (range, 15-84 years). Of the 67 biopsies, five were non-diagnostic and inaccurate and thus unsuccessful (7%); five were diagnostic but inaccurate and thus unsuccessful (7%); 57 were diagnostic and accurate thus successful (85%). These results were comparable with results published in the radiology literature. CONCLUSIONS: The success rate of CT-guided biopsies using a low-dose protocol is comparable to published rates for conventional dose biopsies. The implemented low-dose protocol did not change the success rate of CT-guided musculoskeletal biopsies.

Intra-articular calcifications following arthroscopic ACL reconstruction: prevalence and possible significance.

PURPOSE: The goal of our study was to determine the frequency of intra-articular calcifications on initial postoperative radiographs following arthroscopic ACL reconstruction, describe their appearance, hypothesize their etiology, and determine their significance. MATERIALS AND METHODS: Review of records and post-operative radiographs for individuals undergoing arthroscopic ACL reconstruction at our institution identified 758 knees between November 2002 and April 2010. All patients underwent femoral and tibial tunnel drilling regardless of graft source. All but 23 underwent notchplasty. RESULTS: Intra-articular calcifications on initial postoperative radiographs were observed in 252 knees. The majority of calcifications were curvilinear, paralleling the posterior femoral condyles. Nineteen of the patients with calcifications on initial studies had repeat radiographs within 6 years. The calcifications resolved in every case. CONCLUSIONS: This study shows that intra-articular calcifications are a common finding on initial post-operative radiographs following ACL reconstruction. We feel they are of doubtful clinical significance, and in our limited experience, they eventually resolve. They should not be confused with chondrocalcinosis or vascular calcification.

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.

Relevance of compartmental anatomic guidelines for biopsy of musculoskeletal tumors: retrospective review of 363 biopsies over a 6-year period.

PURPOSE: To retrospectively assess percutaneous core needle biopsies performed by radiologists and the association with tumor seeding along the biopsy tract when anatomic compartment guidelines are not consistently observed. MATERIALS AND METHODS: Retrospective data from computerized patient records and digital images from 363 consecutive computed tomography-guided biopsies of the lower extremity (thigh and leg) performed by radiologists at a single institution from August 2002 to August 2008 were analyzed for breaches of biopsy guidelines. RESULTS: Of the 363 biopsies, 243 (67%) were of soft tissue lesions and 120 (33%) were of bony lesions. There were 188 (52%) malignant and 175 (48%) benign lesions. The following biopsy breaches were observed: 13 (3.6%) of anatomic compartment, 42 (11.6%) of "vital structures," and 82 (68.3%) of needle path for bony tumors. Vital structures as defined by the literature included, but were not limited to, the following: knee joint capsule, greater trochanteric bursa, rectus femoris and vastus intermedius muscles, tibial tubercle, peroneus brevis and peroneus longus distal tendons, and neurovascular bundles. No cases of tumor recurrences could be attributed to needle seeding along a biopsy tract for any of these biopsy guideline breaches. CONCLUSIONS: The concern for needle tract seeding with musculoskeletal tumors is more widespread than the evidence supporting it as a significant or frequent complication. In this study, breaching anatomic compartment, vital structures (other than neurovascular structures), and suggested exact needle path guidelines were not associated with needle tract seeding in the lower extremity.

Imaging of the shoulder: a comparison of MRI and ultrasound.

Magnetic resonance imaging (MRI) is well established as a powerful imaging modality for the shoulder. In the last decade, ultrasound has emerged as an effective imaging option, alongside MRI, for evaluation of the shoulder. With MRI and ultrasound, clinicians now have two viable advanced imaging options for the diagnostic evaluation of shoulder pain. This article discusses the advantages and disadvantages of ultrasound and MRI for the shoulder. Applications where ultrasound is considered the imaging test of choice, those where MRI is more advantageous, and those where both ultrasound and MRI are viable alternatives for shoulder imaging are discussed.

The Posterior Transtriceps Approach for Intra-articular Elbow Arthrography: A Painless Method?

We determined the diagnostic and patient experience advantage of the transtriceps approach for elbow arthrograms. MRIs of two patients who underwent an MRI arthrogram of the elbow in May and June 2022 were retrospectively evaluated. All procedures were performed under fluoroscopic guidance with the patient in the prone position and the arm of interest extended above the head, and the elbow of interest flexed at 90 degrees. A 25 gauge needle was utilized. All MRI examinations were performed on 3-Tesla MRI scanners (Siemens, Hamburg, Germany) and in accordance with our institution's standard elbow arthrogram MRI protocol. The arthrogram was deemed successful if contrast was visualized in the elbow joint, and the MRI examinations were assessed for diagnostic ability and extra-articular leakage. Patient comfort and pain were also assessed. Both arthrograms demonstrated adequate contrast in the elbow joint, and the MRIs confirmed no leakage of contrast or bubbles. The patients felt 0 pain during the procedure on a scale of 0-10. Although the radiocapitellar approach is commonly used for elbow arthrograms, we found the transtriceps approach to be diagnostically sound, painless, and easier to perform.

Lucent Patellar Lesions: A Pictorial Review.

A radiographically lucent patellar lesion may represent a variety of etiologies, ranging from more commonly seen degenerative, metabolic, infectious, developmental, posttraumatic, postoperative causes to rarer benign and malignant neoplasms. Clinical symptoms, surgical history, laboratory values, and radiographic features may help narrow the differential. In addition, radiographic features such as circumscribed borders and sharply delineated margins favor benign lesions while ill-defined margins suggest malignant etiologies. This case series illustrates the imaging findings and explores relevant clinical findings in a variety of interesting lucent patellar lesions.

Revisiting CT-guided percutaneous core needle biopsy of musculoskeletal lesions: contributors to biopsy success.

OBJECTIVE: The purpose of this article is to investigate potential technical, imaging, and histopathologic contributors to the success of CT biopsy. MATERIALS AND METHODS: Four hundred forty-four consecutive CT biopsies of musculoskeletal lesions performed from 2005 to 2008 were retrospectively classified as diagnostic or nondiagnostic and as accurate or inaccurate. A biopsy was considered as diagnostic if it provided a definitive pathologic diagnosis or was clinically useful; as accurate if it was concordant with the ultimate diagnosis with respect to identification of malignancy, grade, and histopathologic features; and as successful if it was both diagnostic and accurate. Biopsy success rate, diagnostic yield, and accuracy were assessed according to lesion location, use of sedation, biopsy equipment type, bone lesion matrix type, and lesion histologic type (i.e., bone or soft-tissue origin, malignant or benign neoplasm, and low-or intermediate-to-high-grade neoplasm). RESULTS: Of 444 biopsies, 71% were diagnostic, 86% were accurate, and 70% were successful. Biopsy success and diagnostic yield were greater in bone lesions, malignant neoplasms, and intermediate-to-high-grade neoplasms compared with soft-tissue lesions (p < 0.01), benign neoplasms (p < 0.0001), and low-grade neoplasms (p < 0.0001). Success and diagnostic yield were not significantly associated with technical or imaging factors. Biopsy accuracy was not associated with any of the tested variables. Of the 128 nondiagnostic biopsy results, 53% were accurate with respect to subsequent surgical pathologic findings. Most of these biopsy results were of benign soft-tissue lesions. CONCLUSION: CT biopsy of musculoskeletal lesions is accurate and effective. It may be limited in the evaluation of benign and low-grade soft-tissue neoplasms.

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.