Faculty Bibliography

Preoperative localization of nonpalpable breast lesions using a radar reflector surgical guidance system has become commonplace, but the clinical utility of this emerging technology in the musculoskeletal system has not yet been well established. The system components include a console, a handpiece, an implanted radiofrequency reflector that works as a lesion marker, and an infrared light-emitting probe to guide the surgeon. The reflector can be deployed to localize small nonpalpable nodules within the subcutaneous fat as well as lesions within the deeper soft tissues. It can also be used for lymph nodes and foreign bodies. Localization can be performed both before and after treatment. The objective of this article is to describe the potential applications and our technique and initial experience for radar-reflector localization within the musculoskeletal system.

A variety of foot and ankle pathologies can impair patient's daily activities, ultimately requiring surgical management. However, with improvements in image-guided intervention, the joints, soft tissues, and osseous structures may be accessible using various percutaneous techniques as a potential alternative therapeutic tool, avoiding the need for surgery with its associated risks and morbidity. This article discusses the potential range of image-guided interventional treatments. Injections, aspiration, biopsies, cryoablation, and radiofrequency ablation are described. Newer novel treatments are also covered. Finally, the common pathologies of Morton's neuroma, Achilles tendinopathy, and plantar fasciitis are addressed.

Postoperative MR imaging of joints is now commonly requested, yet artifacts caused by metallic orthopedic implants remain a significant challenge during image interpretation. Effective artifact reduction is essential to identify postsurgical complications, such as prosthesis loosening, infection, adverse local tissue reaction, and periarticular soft tissue injuries. This article reviews basic and advanced metal artifact reduction MR imaging techniques applied to various clinical protocols for successful postoperative MR imaging of small and large joints.

OBJECTIVES/OBJECTIVE:To determine the incidence of infectious complications following ultrasound-guided musculoskeletal interventions performed with a disinfected uncovered ultrasound transducer footprint. METHODS:Electronic medical records of all patients who underwent an ultrasound-guided musculoskeletal procedure (including injection, calcific lavage, or ganglion cyst aspiration) performed by any of the 14 interventional musculoskeletal radiologists at our institution between January 2013 and December 2018 were retrospectively reviewed to identify procedure site infections. Biopsies and joint aspirations were excluded. The procedures were performed using a disinfected uncovered transducer footprint. First, an automated chart review identified cases with (1) positive answers to the nurse's post-procedure call, (2) an International Classification of Diseases (ICD) diagnostic code related to a musculoskeletal infection, or (3) an antibiotic prescription within 30 days post-procedure. Then, these cases were manually reviewed for evidence of procedure site infection. RESULTS:In total, 6511 procedures were included. The automated chart review identified 3 procedures (2 patients) in which post-procedural fever was reported during the nurse's post-procedure call, 33 procedures (28 patients) with an ICD code for a musculoskeletal infection, and 220 procedures (216 patients) with an antibiotic prescription within 30 post-procedural days. The manual chart review of these patients revealed no cases of confirmed infection and 1 case (0.015%) of possible site infection. CONCLUSIONS:The incidence of infectious complications after an ultrasound-guided musculoskeletal procedure performed with an uncovered transducer footprint is extremely low. This information allows radiologists to counsel their patients more precisely when obtaining informed consent. KEY POINTS/CONCLUSIONS:• Infectious complications after ultrasound-guided musculoskeletal procedures performed with a disinfected uncovered transducer footprint are extremely rare.

OBJECTIVE:This study aimed to investigate patient-specific, lesion-related, and technical factors that potentially influence diagnostic yield of computed tomography (CT)-guided biopsies of bone lesions. METHODS:Computed tomography-guided bone lesion biopsies performed over a 2-year period were retrospectively reviewed, including image review and electronic medical records for pathology reports and clinical follow-up. Lesions were tabulated by prebiopsy CT and magnetic resonance imaging features. Patients with nondiagnostic biopsies were assessed for presumptive clinical diagnosis and management. RESULTS:Nondiagnostic pathology results were obtained in 31 of 156 cases (19.87%), among which diagnoses were confirmed by other tissue sampling in 9; clinical follow-up of up to 2 years yielded no diagnosis in 10 and presumptive diagnoses in 12. The nondiagnostic biopsy rate of long bone lesions was higher than that of other bone lesions (odds ratio, 3.46; 95% confidence interval, 1.32-9.09). There were no significant differences in patient American Society of Anesthesiologists class, mean body mass index, sedation method, number of cores, or needle gauge between diagnostic and nondiagnostic biopsy cohorts. Diagnostic yield was not significantly different between occult, lytic, or sclerotic lesions. There was no difference in diagnostic yield regarding presence of cortical break, gadolinium enhancement, or lesion depth. Magnetic resonance imaging was obtained before biopsy in significantly more nondiagnostic cases compared with diagnostic cases (P = 0.027). CONCLUSIONS:Computed tomography-guided biopsies had a nondiagnostic rate of 19.87%, and lesions in the long bones of the extremities were disproportionately common among this group. There was no significant association between biopsy results and several patient-specific, lesion-related, and technical factors.

Total hip arthroplasty and hip preservation surgeries have substantially increased over the past few decades. Musculoskeletal imaging and interventions are cornerstones of comprehensive postoperative care and surveillance in patients undergoing established and more recently introduced hip surgeries. Hence the radiologist's role continues to evolve and expand. A strong understanding of hip joint anatomy and biomechanics, surgical procedures, expected normal postoperative imaging appearances, and postoperative complications ensures accurate imaging interpretation, intervention, and optimal patient care. This article presents surgical principles and procedural details pertinent to postoperative imaging evaluation strategies after common hip surgeries, such as radiography, ultrasonography, computed tomography, and magnetic resonance imaging. We review and illustrate the expected postoperative imaging appearances and complications following chondrolabral repair, acetabuloplasty, osteochondroplasty, periacetabular osteotomy, realigning and derotational femoral osteotomies, and hip arthroplasty.

Real-time dynamic magnetic resonance imaging (MRI) in the musculoskeletal system touts the ability to perceive in vivo joint kinematics, which is particularly attractive for diagnosing dynamic pathologies such as joint instability or impingement syndromes.The clinical utility of dynamic MRI in the musculoskeletal system is wide ranging, from patellofemoral kinematics to imaging of the hip in femoroacetabular impingement and also dynamic spine imaging. Patellofemoral instability is an ideal diagnostic target, as knee flexion and extension are easily performed in an MRI scanner, and dynamic measurements have been correlated to clinical and static radiologic parameters of instability. Proving the clinical utility of this MRI technique requires rigorous technical standardization and definition of normal patellofemoral motion parameters. Validated imaging methods and rigorously defined normal range data are required to light the path forward, and the video format of dynamic MRI is also ideal for advancing patient-centered care, improving patient literacy on their condition, and offering a potential catalyst for shared decision-making between surgeons and their patients.

PURPOSE/OBJECTIVE:To present a novel 3T 24-channel glove array that enables hand and wrist imaging in varying postures. METHODS:The glove array consists of an inner glove holding the electronics and an outer glove protecting the components. The inner glove consists of four main structures: palm, fingers, wrist, and a flap that rolls over on top. Each structure was constructed out of three layers: a layer of electrostatic discharge flame-resistant fabric, a layer of scuba neoprene, and a layer of mesh fabric. Lightweight and flexible high impedance coil (HIC) elements were inserted into dedicated tubes sewn into the fabric. Coil elements were deliberately shortened to minimize the matching interface. Siemens Tim 4G technology was used to connect all 24 HIC elements to the scanner with only one plug. RESULTS:The 24-channel glove array allows large motion of both wrist and hand while maintaining the SNR needed for high-resolution imaging. CONCLUSION/CONCLUSIONS:In this work, a purpose-built 3T glove array that embeds 24 HIC elements is demonstrated for both hand and wrist imaging. The 24-channel glove array allows a great range of motion of both the wrist and hand while maintaining a high SNR and providing good theoretical acceleration performance, thus enabling hand and wrist imaging at different postures to extract kinematic information.

PURPOSE/OBJECTIVE:To evaluate the association between postoperative cam lesion measured by the "femoroacetabular impingement resection (FAIR) arc" and 2-year patient outcomes following hip arthroscopy. METHODS:A retrospective review of prospectively gathered data from 2013-2017 was performed. All patients who underwent hip arthroscopy for FAI with ≥ 2-year follow-up were included. Cam FAIR arc measurements were made pre and postoperatively on a 45° Dunn view radiograph. The clinical effect of postoperative cam maximal radial distance (MRD) was assessed using the modified Harris Hip Score (mHHS) and Non-Arthritic Hip Score (NAHS). Patients were divided into subgroups based on relationship to the mean and standard deviations for cam MRD. One half standard deviation above the mean was found to be 3.15 mm. RESULTS:=0.004). Subgroup analysis demonstrated that patients in the cam MRD < 3.15 mm group had significantly higher mHHS (89.7 vs 70.0 p<0.001) and NAHS scores (90.5 vs 72.9, p<0.001) than those in the >3.15 mm group. Additionally, more patients in the <3.15 mm group reached the minimal clinically important difference (MCID) (95.2% vs 78.9%, p=0.048) and were above patient acceptable symptomatic state (PASS) (95.2% vs 52.6%, p<0.001) compared to the >3.15 mm group. CONCLUSION/CONCLUSIONS:Patients with a lower postoperative cam MRD relative to the FAIR arc demonstrated significantly improved outcomes as compared to those with higher postoperative MRD at two-year follow-up.

PURPOSE/OBJECTIVE:To describe our experience using ultrasound (US) to evaluate postoperative complications in the presence of in situ shoulder arthroplasty. METHODS:Review of patients who underwent US evaluation following total shoulder arthroplasty (TSA), reverse total shoulder arthroplasty (RTSA) or hemiarthroplasty from 2007 to 2020. All studies were reviewed independently by two musculoskeletal radiologists to assess for joint effusion, periarticular collection, and characterization of associated rotator cuff tears. Tendon tears were assessed with respect to (1) thickness: low grade (<50% thickness), high grade (>50% thickness), full thickness; (2) morphology (focal vs. diffuse) and location (insertion vs. critical zone). Inter-reader agreements were determined using Cohen's kappa test. RESULTS:Ninety-seven studies were performed in 72 patients following TSA, RTSA, or hemiarthroplasty. Thirty-seven exams were solely for diagnostic purposes, and 59 were for guiding joint or periarticular collection aspiration. Twenty-eight studies assessed the cuff tendons post TSA. The mean time between surgery and US examination was 29.2 months. Complete or high-grade tears were identified in 8/28 (28.6%) diagnostic exams. The most commonly torn tendon among TSA patients was the subscapularis, with 13/28 (46.4%) demonstrating at least partial tearing. Inter-reader agreement was excellent for presence of effusion (k = 0.79, p < .001) and periarticular collection (k = 0.87, p < .001), and excellent agreement for presence of subscapularis tear (k = 0.78, p < .001), with fair agreement for assessment of supraspinatus (k = 0.66, p < .001) and infraspinatus (k = 0.60, p < .001) tears. CONCLUSION/CONCLUSIONS:The most commonly torn tendon following anatomic TSA identified by US was the subscapularis, which was torn or deficient in 46.4% of cases. The majority of studies were performed for the guidance of percutaneous aspiration.