Does MRI alter management in patients 60 years and older with chronic knee pain: correlation with radiographs and clinical parameters.

OBJECTIVE: To determine if MRI altered management in patients ≥ 60 years old with chronic knee pain. MATERIALS AND METHODS: Consecutive patients ≥ 60 years old with knee MRI and radiographs within 90 days were included. Exclusion criteria included mass/malignancy, recent trauma, and infection. Standing AP and PA flexion views were evaluated using Kellgren-Lawrence (KL) and International Knee Documentation Committee (IKDC) scales. Pertinent clinical history was recorded. MRIs were considered to alter management if subchondral fracture was identified or subsequent arthroscopy was performed due to an MRI finding. RESULTS: Eighty-five knee MRI/radiograph exams were reviewed; mean 68.2 years (60-88), 47:38 F:M. Twenty knee MRIs (24%) had either a subchondral fracture (n = 9) or meniscal tear (n = 11) prompting arthroscopy. On PA flexion view, 0/20 of these studies had KL grade 4 and 70% (14/20) had KL grade 0-1 compared to the remaining MRIs having 15.4% (10/65) KL grade 4 and 38.5% (25/65) KL grade 0-1 (p = 0.03). A 10-pack-year tobacco history, 38% vs 18%, was associated with a subchondral fracture or arthroscopy (p = 0.06). Subchondral fractures were more prevalent in older patients (mean 72.4 vs 67.7 years; p = 0.03). CONCLUSION: In patients ≥ 60 years old with chronic knee pain, MRI altered management in ~ 24% of cases; 70% in patients with KL grade 0-1, and none in patients with KL grade 4. MRI may benefit older patients with minimal osteoarthritis but not those with end-stage disease. Patients with ≥ 10 pack years of smoking may also benefit from MRI.

Cone-Beam CT of the Extremities in Clinical Practice.

Cone-beam CT (CBCT) is a promising tool with increasing applications in musculoskeletal imaging due to its ability to provide thin-section CT images of the appendicular skeleton and introduce weight bearing, which accounts for loading forces that typically interact with and affect this anatomy. CBCT devices include an x-ray source directly opposite a digital silicon detector panel that performs a single rotation around an object of interest, obtaining thin-section images. Currently, the majority of research has been focused on the utility of CBCT with foot and ankle pathologic abnormalities, due to the complex architectural arrangement of the tarsal bones and weight-bearing nature of the lower extremities. Associated software can provide a variety of options for image reconstruction, including metal artifact reduction, three-dimensional biometric measurements, and digitally reconstructed radiographs. Advancements in this technology have allowed imaging of the knee, hip, hand, and elbow. As more data are published, it is becoming evident that CBCT provides many additional benefits, including fast imaging time, low radiation dose, lower cost, and small equipment footprint. These benefits allow placement of CBCT units outside of the traditional radiology department, including the orthopedic clinic setting. These technologic developments have motivated clinicians to define the scope of CBCT for diagnostics, surgical planning, and longitudinal imaging. As efforts are made to create standardized protocol and measurements, the current understanding and surgical approach for various orthopedic pathologic conditions will continue to shift, with the hope of improving outcomes. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Weight-Bearing CT with Maximum Ankle Dorsiflexion to Identify Impingement and Tibial Plafond Stress Fracture: A Case Report.

CASE: A 25-year-old male pole vaulter presented with several months of right ankle pain. Radiographs showed an anterior tibial osteophyte with a small intra-articular body suggesting impingement. Weight-bearing computed tomography (CT) revealed an associated tibial plafond stress fracture. Subsequent arthroscopy with osteophyte resection and loose body removal significantly improved symptoms, and he gradually resumed training. CONCLUSION: Stress fractures should always be considered in athletes with ankle pain. A unique aspect of this case was the use of weight-bearing CT in diagnosis and surgical planning. To our knowledge, this is the first described case in which weight-bearing CT was used in this fashion.

CT-guided quadratus femoris injection for ischiofemoral impingement.

OBJECTIVES: To describe the technique, efficacy, and safety of CT-guided quadratus femoris injection with corticosteroid and local anesthetic for the treatment of ischiofemoral impingement in a series of cases at our institution. METHODS: Cases of CT-guided quadratus femoris injections from 2000 to 2021 were identified in the enterprise-wide electronic medical record of our institution. Patient charts and our institutional picture archiving and communication system (PACS) were searched for demographics, pain level on a 0-10 scale before and immediately following the procedure, procedure technique, and follow-up outcomes if available. RESULTS: There were 13 cases among 12 patients with clinical and imaging findings of ischiofemoral impingement included in this study. Of the 12 patients, 10 were female and two were male. There were eight posterior approaches and five posterolateral approaches. Of the 13 cases, 11 resulted in immediate pain reduction. The median reduction in pain score was four (average 3.46, range 0-8.5). There was no statistically significant difference in pain reduction between the posterior approach cases and the posterolateral approach cases. No cases reported immediate complications or increases in pain score. Of the 12 cases, seven resulted in at least 1 month of pain relief, three had subsequent surgeries, and three had no follow-up. CONCLUSION: CT-guided quadratus femoris injection is safe and effective for treating ischiofemoral impingement. Further and larger scale study is needed to fully delineate differences in technique effectiveness. KEY POINTS: • CT-guided quadratus femoris injection is safe and effective for treating ischiofemoral impingement. • We found no statistically significant difference in pain reduction between the posterior approach and the posterolateral approach.

Percutaneous biopsy of musculoskeletal tumors and the potential for needle tract seeding: technical considerations, current controversies, and outcomes.

Multidisciplinary communication and planning between the musculoskeletal radiologist and orthopedic oncologist are essential for proper biopsy planning when a primary musculoskeletal malignancy is suspected. Image-guided percutaneous biopsy allows for real-time visualization of the biopsy needle and surrounding structures, combining high diagnostic accuracy with safety and cost-effectiveness. However, determining a surgically optimal biopsy trajectory for a mass can be technically challenging due to critical surrounding anatomy or challenging needle approach angles. Inappropriately placed biopsies can have serious repercussions on patient function and oncological survival. The potential for needle tract seeding and local recurrence after biopsy of sarcoma has been central to the debate regarding the need for excision of the biopsy tract. This multidisciplinary review highlights current controversies in the field, including the issue of core needle biopsy tracts and their excision, technical considerations and advances in image-guidance in the setting of challenging biopsies, advances in histopathological diagnostics with implications for targeted therapy in sarcoma, as well as surgical and oncological outcomes after needle tract biopsy.

Quantifying misdiagnosis rates from cross-calibration biases and precision errors in dual-energy X-ray absorptiometry of the femoral neck.

BACKGROUND: Dual-energy X-ray absorptiometry (DXA) is an exam that measures areal bone mineral density (aBMD) and is regularly used to diagnose and monitor osteoporosis. Except for exam quality issues such as operator error, the quantitative results of an exam are not modified by a radiologist or other physician. DXA cross-calibration errors can shift diagnoses, conceivably leading to alternate intervention decisions and patient outcomes. PURPOSE: After identifying and correcting a cross-calibration bias of 3.8% in our two DXA scanners' aBMD measurements, we investigated misdiagnosis rates for given cross-calibration errors in a single patient cohort to determine the impact on patient care and the value of cross-calibration quality control. METHODS: The studied cohort was 8012 patients of all ages and sexes with femoral neck exams that were scanned on a single DXA unit from October 1, 2018 to March 31, 2021. There were six subcohorts delineated by age and sex, three female groups and three male groups. Data reporting focused on the highest risk subcohort of 2840 females aged 65 or older. The DXA unit had no calibration changes during that time. Only one femoral neck-left or right-was randomly chosen for analysis. Patients with multiple qualifying exams within the time interval had one exam randomly chosen. The proof-of-principle simulation shifted the aBMD values within a range of ±10%, ±8%, ±6%, ±4%, ±3.5%, ±3%, ±2.5%, ±2%, ±1.5%, ±1%, ±0.5%, and 0 (no shift); the cross-calibration shifts were informed by published results and institutional experience. Measurement precision was modeled by randomly sampling a Gaussian distribution characterized by the worst acceptable least significant change (LSC) of 6.9%, with 100 000 samplings for each patient. T-scores were recalculated from the shifted aBMD values, followed by reassigned diagnoses from the World Health Organization's T-score-based scheme. RESULTS: The unshifted original subcohort of women aged 65 and older had 599 normal diagnoses (21.1% of the cohort), 1784 osteopenia diagnoses (62.8%), and 455 osteoporosis diagnoses (16.1%). Osteoporosis diagnosis rates were highly sensitive to aBMD shifts. At the extrema, a -10% aBMD shift led to +161% osteoporosis cases, and a +10% aBMD shift led to -64.5% osteoporosis cases. Within the more plausible ±4% aBMD error range, the osteoporosis diagnosis rate changed -10.5% per +1% aBMD shift as indicated by linear regression (R2  = 0.98). Except for the men aged 49 years and younger subcohort, the total cohort and five subcohorts had fit line slopes ranging between -9.7% and -12.1% with R2 ≥ 0.98. Cross-calibration bias had greater influence for diagnosis count rates compared to measurement precision, that is, LSC. CONCLUSIONS: These results quantify the degree of misdiagnosis that can occur in a clinically relevant cohort due to cross-calibration bias. In medical practices where patients may be scanned on more than one DXA unit, ensuring cross-calibration quality is a critical and high-value quality control task with direct impact on patient diagnosis and treatment course. The clinical impact and incidence of poor DXA quality control practices, and cross-calibration in particular, should be studied further.

Angiolipoma: a review of 778 lesions in 344 patients.

BACKGROUND: Angiolipomas are benign subcutaneous nodules that are commonly multifocal and easily overlooked by those not familiar with their appearance. The objective of this study was to identify the spectrum of the clinical and imaging features of this lesion, to include MR, CT, and US features. METHODS: A retrospective review of our institutional pathology database for biopsy-proven cases of angiolipoma between January 1, 2019, through December 31, 2021, was done. We identified 334 patients who underwent surgical resection of 788 individual lesions. MR imaging studies were available in 43 cases, CT in 39 cases, and ultrasound imaging in 72 cases. Clinical features (patient age, gender, surgical indication, number of lesions) were reviewed. Imaging feature analysis included the anatomic location, content of fat, vascularity, and modality-specific imaging features. RESULTS: All 778 angiolipomas were located in the subcutaneous tissues (median size, 2.4 cm, range 0.4-7.7 cm), with over 51% located in the upper extremity. The most common presentation was a symptomatic mass or slowly growing symptomatic mass. Imaging showed a subcutaneous lesion with a lobulated bean shape, which typically abutted the skin. Intralesional fat was identified in 85% of lesions on CT and MRI. Vessels were commonly seen on CT and MR, with enhancement best seen on MR. On US, lesions were heterogeneous and mildly hyperechoic, most often with no identifiable vascularity. CONCLUSION: Angiolipomas typically have characteristic imaging features. Awareness of this diagnosis and the spectrum of its imaging features is important and can facilitate a definitive diagnosis.

Carbon-fiber-reinforced polyetheretherketone orthopedic implants in musculoskeletal and spinal tumors: imaging and clinical features.

Carbon-fiber-reinforced polyetheretherketone (CFR-PEEK) orthopedic implants are gaining popularity in oncologic applications as they offer many potential advantages over traditional metallic implants. From an imaging perspective, this instrumentation allows for improved evaluation of adjacent anatomic structures during radiography, computed tomography (CT), and magnetic resonance imaging (MRI). This results in improved postoperative surveillance imaging quality as well as easier visualization of anatomy for potential image-guided percutaneous interventions (e.g., pain palliation injections, or ablative procedures for local disease control). CFR-PEEK devices are also advantageous in radiation oncology treatment due to their decreased imaging artifact during treatment planning imaging and decreased dose perturbation during radiotherapy delivery. As manufacturing processes for CFR-PEEK materials continue to evolve and improve, potential orthopedic applications in the spine and appendicular skeleton increase. An understanding of the unique properties of CFR-PEEK devices and their impact on imaging is valuable to radiologists delivering care to orthopedic oncology patients in both the diagnostic and interventional settings. This multidisciplinary review aims to provide a comprehensive insight into the radiologic, surgical, and radiation oncology impact of these innovative devices.

Bone and Soft Tissue Tumors: Interventional Techniques for Diagnosis and Treatment.

Radiologists have an integral role in the diagnosis of bone and soft-tissue tumors beyond image interpretation. Image-guided biopsies are used to diagnose and stage musculoskeletal tumors. This article reviews the steps of minimally invasive image-guided biopsies, from prebiopsy planning through postbiopsy pathology follow-up. Helpful techniques to perform and troubleshoot these procedures adequately and safely are detailed. Radiologists are also expanding the treatment options available for many benign and malignant bone and soft-tissue tumors. Some of these more frequently performed procedures include percutaneous thermal ablation and cementoplasty. The evidence, indications, and basic principles of these interventional procedures are also discussed.

A novel meniscofemoral ligament variant intra-substance to the PCL.

While much detail is known about each anatomic structure of the knee and its contributory effect on biomechanics, our understanding is still evolving. In particular, the function of the meniscofemoral ligaments and their anatomical variants have yet to be fully described. In this report, a never-before-described anatomical meniscofemoral ligament variant intra-substance to the PCL is presented. Arthroscopists should be aware of the novel variant as a growing number of studies have demonstrated the biomechanical importance of the meniscofemoral ligaments in protecting the lateral meniscus and supporting the function of the PCL.Level of Evidence: IV.

MRI Evaluation of Patients Before and After Interventions for Benign Prostatic Hyperplasia: An Update.

Transurethral resection of the prostate is the most commonly performed procedure for the management of patients with lower urinary tract symptoms attributed to benign prostatic hyperplasia (BPH). However, in recent years, various minimally invasive surgical therapies have been introduced to treat BPH. These include laser-based procedures such as holmium laser enucleation of the prostate and photoselective vaporization of the prostate as well as thermal ablation procedures such as water vapor thermal therapy (Rezum), all of which result in volume reduction of periurethral prostatic tissue. In comparison, a permanent metallic device (UroLift) can be implanted to pull open the prostatic urethra without an associated decrease in prostate size, and selective catheter-directed prostate artery embolization results in a global decrease in prostate size. The goal of this article is to familiarize radiologists with the underlying anatomic changes that occur in BPH as visualized on MRI and to describe the appearance of the prostate on MRI performed after these procedures. Complications encountered on imaging after these procedures are also discussed. Although MRI is not currently used in the routine preprocedural evaluation of BPH, emerging data support a role for MRI in predicting postprocedure outcomes.

The Magnet Is Sometimes "Off"-Practical Strategies for Optimizing Challenging Musculoskeletal MR Imaging.

To describe practical solutions to the unique technical challenges of musculoskeletal magnetic resonance imaging, including off-isocenter imaging, artifacts from motion and metal prostheses, small field-of-view imaging, and non-conventional scan angles and slice positioning. Unique challenges of musculoskeletal magnetic resonance imaging require a collaborative approach involving radiologists, physicists, and technologists utilizing optimized magnetic resonance protocols, specialized coils, and unique patient positioning, in order to reliably diagnose critical musculoskeletal MR image findings.

Sonography of the Post-Operative Rotator Cuff: Normal Postoperative Findings, Postsurgical Complications and Common Artifacts.

This review sets forth an approach to performing and interpreting shoulder ultrasound in patients with prior rotator cuff repair and presents a comprehensive review of normal expected findings, postsurgical complications and common artifacts encountered in clinical practice.

Dark Cartilage Lesions in the Knee: MRI Appearance and Clinical Significance.

Early investigations into the magnetic resonance imaging (MRI) appearance of articular cartilage imaging relied on assessment of the morphology, with subsequent investigators reporting identifying increased T2 signal intensity, bright signal, in degenerated cartilage. The cartilage "black line sign" is a finding that has recently been described in the radiology literature to characterize cartilage pathology. This sign refers to a focal linear hypointense signal within articular cartilage that is oriented perpendicular to the subchondral bone on T2-weighted MRI. The diagnostic significance and clinical relevance of this sign is debated. Since its first description, several papers have further delineated the etiology, prevalence, and clinical relevance of these and other dark cartilage abnormalities. The intent of this article is to summarize these findings, with hopes of bringing to light the importance of dark cartilage lesions and their clinical implication in the world of knee surgery. We will briefly discuss the most probable etiologies of dark cartilage abnormalities and the major factors determining the unique signal intensity. The described anatomical patterns of this finding, the clinical importance, potential mimics, and current treatment recommendations will be reviewed.

Fluoroscopy-guided bone marrow aspiration and biopsy: technical note.

Bone marrow aspiration and biopsy is a valuable procedure commonly utilized for evaluation of hematologic abnormalities, nonhematologic malignancies, metabolic abnormalities, tumor treatment response, and suspected infection in patients with fever of unknown origin. Imaging guidance with computed tomography (CT) is commonly utilized to improve safety and effectiveness of the procedure. Considering progressively increasing volume of complex CT-guided procedures as well as diagnostic CT imaging in most practices potentially resulting in limited availability of CT, a technique for fluoroscopy-guided bone marrow aspiration and biopsy is described with focus on advantages, which could be beneficial to most busy practices in modern era radiology.

Ulnar shaft stress fractures in fast-pitch softball pitchers: a case series and proposed mechanism of injury.

BACKGROUND: Stress fractures of the upper extremities in athletes are important injuries for radiologists to appreciate despite being far less common than stress fractures of the lower extremities. Among upper extremity stress fractures, those involving the olecranon have been well described in overhead pitching athletes. Isolated stress fractures of the ulnar shaft however are less commonly reported in the literature and considered to be rare. We have observed a correlation between young patients with ulnar shaft stress fractures and the activity of fast-pitch softball pitching. CASE REPORTS: In this series, we present the imaging findings in four cases of ulnar shaft stress fractures in softball pitchers who presented with insidious onset forearm pain. Furthermore, a review of the literature focusing on softball pitching mechanics is provided to offer a potential underlying mechanism for the occurrence and location of these injuries. CONCLUSION: An awareness of the imaging appearance of ulnar shaft stress fractures along with an understanding of its proposed mechanism will facilitate accurate and timely imaging diagnosis of this injury by the radiologist.

Digital Subtraction Air Arthrography: An Innovative Technique for Needle Tip Location Confirmation.

PURPOSE: This article describes an innovative technique to confirm needle tip positioning using digital subtraction fluoroscopy and air within a targeted joint. MATERIALS AND METHODS: Digital subtraction fluoroscopy with air was utilized to confirm intra-articular needle tip position in 12 joints over a 14-month period at a single institution. Procedural details were recorded for each joint including: joint location, fluoroscopy time, patient age, patient body mass index, and change in subjective pain rating following the injection. Shoulder and hip phantoms were utilized to compare radiation dose differences between fluoroscopy with digital subtraction technique and fluoroscopy without digital subtraction technique. RESULTS: All of the 12 injections were technically successful with air clearly visualized within each targeted joint and subjective pain ratings either did not change or decreased following the injection. Patient age ranged from 51 to 87 years old and body mass index values ranged from 19.2 to 37.1 kg/m2. Fluoroscopy times ranged from 11.1 to 32.9 seconds. There were no complications during or immediately following the injections. The addition of digital subtraction technique increased the skin dose at the shoulder by approximately 2.6 times and at the hip by approximately 2.2 times. Likewise, the cumulative dose at the shoulder increased by approximately 2.7 times and at the hip by 2.0 times. CONCLUSION: Fluoroscopic digital subtraction air arthrography is a valuable option for needle tip confirmation when using air as a contrast agent. This novel combination of established fluoroscopic techniques can be incorporated into most clinical practices.