Faculty Bibliography

Objective: At the conclusion of this activity, participants will understand the basic principles of MR-US fusion and potential applications to the musculoskeletal system. Development of a simple phantom for training will be described. Examples of injections performed to date will be shown to illustrate potential applications and challenges in obtaining adequate registration. Ultrasound guided injections have become increasing utilized over the past several years. In many instances, these derive from direct referrals following MR or CT. Correspondence of abnormalities seen on cross-sectional imaging, however, may not always be readily evident on ultrasound, Examples would include deep seated abnormalities which are not amenable to high frequency transducers or low contrast lesions on gray-scaleultrasound that are highly conspicuous on MR. MR-US co-registration provides a method to visualize the relevant soft tissue anatomy with greater confidence, while allowing for differences in the image acquisition plane. MR-US fusion has largely been applied to abdominal applications, with relatively few musculoskeletal applications reported to date. The basic requirements of registration include having a representative high-resolution MR (or CT) data set, a method to track the transducer orientation in space (usually through a "Flock of Birds technique"), and the selection of internal fiduciary points common to both data sets (minimally 3 points at different locations). Based on phantom data, accuracies of approximately 5mm or less can be achieved. A brief survey of the technical aspects of co-registration will be discussed, followed by the typical sequence employed to achieve registration with musculoskeletal applications in mind. A series of clinical examples will be presented from therapeutic injections, aspirations or biopsies in the musculoskeletlal system performed at our institution. Use of a relatively simply constructed gelatin phantom will also be described to serve as a potential learning tool to improve individual throughput in the early phase of performing these procedures. The challenges, limitations and potential benefits of using real-time co-registration techniques will be discussed.
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Objective: To describe the role of vascularity in assessing bone tendon healing and describe the application of ultrasound contrast agents in quantitative and visual assessment of the vascular following repair with attention to the rotator cuff. Rotator cuff tears are common, having been described in up to 20.7% of the general population and accounting for approximately 75,000 operations in the United States per year. The reported prevalence of failure of rotator cuff repairs has varied in the literature, ranging from 19-94%. Various factors are thought to account for poor healing of the repair, including intrinsic tendon degeneration, fatty infiltration of the muscle and tendon, muscle atrophy, poor bone quality, and weak tendon-to-bone fixation. Experimental studies have shown that bone-tendon healing begins with the formation of fibrovascular scar tissue between the tendon and bone, followed by gradual bone ingrowth into this fibrous interface extending into the native tendon. Tendon repair therefore involves multiple phases: an inflammatory phase, reparative phase and finally remodeling phase. These phases are linked to a variety of growth factors that appear most active in a temporal sequence. Consequently, an area of active investigation is to determine methods to augment bone-tendon and tendon-tendon healing using endogenous growth factors, such as those derived from platelet rich aggregates to promote bone tendon healing. The role of imaging in this scenario is to provide a non-invasive means to potentially determine various phases of healing and to assess the outcomes of either primary repair or interventions meant to augment healing. In the current talk, we briefly describe the sequence of events associated with tendon degeneration, tearing and subsequent bone-tendon healing, following repair. In particular we review the role of contrast enhanced ultrasound in depicting the temporal changes in vascularity following rotator cuff repair.
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Objectives: To describe our experience applying shear wave elastography to the musculoskeletal system, as well as some potential sources of artifact when applying this new technology. Disease states in the musculoskeletal system often manifest as altered tissue morphology evident on conventional gray-scale ultrasound imaging. These states also display other changes, such as altered tissue vascularity and mechanical properties. An example would be the tendon softening associated with tendinosis. US elastography provides a measure of local soft-tissue stiffness by means of mechanical stimulation. Presently, the two most common forms of US elastography measure tissue stiffness and strain by recording (a) how tissues respond to external compression obtained by applying manual pressure (Quasi-static or compression based on response to acoustic radiation force generated by the ultrasound transducer, the latter referred to as Shear-Wave Elastography (SWE). SWE employs a focused acoustic beam generated by the US transducer to compress the underlying tissue, thereby inducing a local shear wave. The speed of that wave, also known as the shear- wave velocity (SWV), is then measured as it propagates through the tissue and displayed as a parametric image or through selective region-of-interest (ROI) analysis, measured in meters per second. SWV provides a quantitative metric of tissue stiffness because it directly relates to the local shear elastic modulus, such that the stiffer the tissue, the greater the SWV. Consequently, some vendors directly display shear wave data as elastic modulus in kilopascals (KPS). In the current discussion, we briefly review some basic principles of shear wave imaging, review some of the common musculoskeletal applications, to date, and describe our experience using SWE in the musculoskeletal system with attention to skeletal muscle and tendons. We review some potential artifacts that the sonographer should be aware of in applying this new technology to tendon and muscle imaging.
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Dancers exert tremendous stresses on the lower extremities rendering them prone to injuries that can curtail training and performance. The goal of this study was to evaluate clinical improvement in a population of elite dancers following treatment with ultrasound-guided platelet-rich plasma (PRP) injections of various lower extremity sites by assessing when they were able to return to dance. Nineteen dancers (13 female, 6 male; ages 15 to 42) were treated between 2009 and 2016 at sites that included: hamstring tendon (1), proximal iliotibial band (1), patellar tendon (3), posterior tibial tendon (5), peroneus brevis tendon (3), plantar fascia (3), and the first metatarsophalangeal (MTP) joint capsule (3). Injections were performed by a single radiologist using the same PRP kit under ultrasound guidance. All patients adhered to standard post-care instructions, including non-weightbearing and avoidance of NSAIDs for at least 2 weeks post-injection. Clinical charts were reviewed for factors including: adherence to post-injection immobilization and physical therapy, physical exam assessments, and milestones in returning to dance. The time-point for returning to dance was defined by attendance of class or rehearsal without symptoms referring to the treated site. Eighteen subjects achieved return to dance, 13 in 6 months or less, and the majority (10) within 3 months of injection. Five subjects required more than 6 months recovery time. These cases all involved foot and ankle sites; of these, two subjects required repeat injections, and both returned to dance within 11 months of the second injection. In the single case where PRP treatment failed, the injury treated was severe plantar fasciopathy with a high-grade central cord tear. It is concluded that ultrasound-guided PRP injections may play a role in the treatment of various lower extremity injuries in elite dancers, with the majority of subjects in this series returning to dance within 6 months. Recovery time may vary depending on the site treated and severity of the presenting injury.

Emerging musculoskeletal applications for local administration of autologous bone marrow aspirate concentrate (BMAC) include treatment of fractures, osteonecrosis, osteochondral injuries, osteoarthritis, ligament injury, tendon injury, and tendonopathies. Ultrasound-guided technique for various BMAC injection sites is detailed in this technical report and our preliminary clinical experience outlined.Five patients, 1 woman and 4 men, were treated with 6 peri/intratendinous (n = 4) or intraarticular (n = 2) BMAC injections between July 5, 2015 and December 31, 2016 for the clinical indications of common hamstrings origin tendinosis (n = 4), hip labral tear (n = 1), and osteochondral lesion of the talus (n = 1).All procedures were technically successful, with BMAC locally administered to the therapeutic target and no procedural complications observed. Clinical follow-up was available for 5 of 6 procedures. Four of 5 injections resulted in self-reported symptomatic improvement (clinical follow-up range, 2-12 months). One 72-year-old man with right common hamstrings origin tendinosis reported no improvement after BMAC injection.The technology is now available to support ultrasound-guided, autologous BMAC administration by the musculoskeletal interventionalist for common indications. Our initial clinical experience is consistent with early reports in the literature. This technique is well tolerated by symptomatic patients on an outpatient basis, and rates of self-reported symptomatic relief are high. Mechanism of action, long-term safety, and long-term clinical efficacy remain largely undefined.

Shoulder pain is one of the most common reasons for musculoskeletal-related physician visits. Imaging plays an important role in identifying the specific cause of atraumatic shoulder pain. This review is divided into two parts. The first part provides a general discussion of various imaging modalities (radiographs, arthrography, nuclear medicine, ultrasound, CT, and MRI) and their usefulness in evaluating atraumatic shoulder pain. The second part focuses on the most appropriate imaging algorithms for specific shoulder conditions including: rotator cuff disorders, labral tear/instability, bursitis, adhesive capsulitis, biceps tendon abnormalities, postoperative rotator cuff tears, and neurogenic pain. 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.

We describe an easily constructed, customizable phantom for magnetic resonance imaging-ultrasound fusion imaging and demonstrate its role as a learning tool to initiate clinical use of this emerging modality. Magnetic resonance imaging-ultrasound fusion can prove unwieldy to integrate into routine practice. We demonstrate real-time fusion with single-sequence magnetic resonance imaging uploaded to the ultrasound console. Phantom training sessions allow radiologists and sonographers to practice fiducial marker selection and improve efficiency with the fusion hardware and software interfaces. Such a tool is useful when the modality is first introduced to a practice and in settings of sporadic use, in which intermittent training may be useful.

BACKGROUND:Previous work evaluating the pronator quadratus (PQ) muscle following volar plate fixation (VPF) of distal radius fractures (DRF) suggests that PQ repair often fails in the postoperative period. The purpose of this investigation was to assess PQ repair integrity following VPF of DRF using dynamic musculoskeletal ultrasonography. METHODS:Twenty adult patients who underwent VPF of DRF with repair of the PQ with a minimum follow-up of 3 months underwent bilateral dynamic wrist ultrasonography. The integrity of the PQ repair, wrist range of motion (ROM) and strength, and functional outcome scores were assessed. RESULTS:Mean patient age at the time of surgery was 59 ± 14 years, and 50% underwent VPF of their dominant wrist. Patients were evaluated at a mean 9 ± 4 months after VPF. All patients had an intact PQ repair. The volar plate was completely covered by the PQ in 55% of patients and was associated with a larger PQ when compared to patients with an incompletely covered volar plate ( P = .026). The flexor pollicis longus tendon was in contact with the volar plate in 20% of patients, with those patients demonstrating a trend toward significantly increased wrist flexion ( P = .053). No difference in ROM, strength, or outcome scores was noted among wrists with completely or incompletely covered volar plates. CONCLUSIONS:The PQ demonstrates substantial durability after repair following VPF. Wrist ROM, strength, and functional outcomes are similar in wrists in which the volar plate is completely or incompletely covered by the repaired PQ.

Purpose: To correlate quantitative shear wave velocities (SWV) in the supraspinatus muscle (SSM) with that of the tendon (SST), and to evaluate whether SSM SWV changes precede morphologic fatty atrophy. Materials and Methods: An IRB-approved, HIPAA-compliant study of 45 patients (22 men, 23 women) with mean age of 59 (range 39-84) was conducted. Grayscale ultrasound and shear wave elastography images of the SST and SSM were performed with a 9MHz linear transducer on a Siemens S3000 scanner with VTIQ software (Siemens). Sample volume SWV values were obtained of the proximal (PSST) and distal tendon (DSST). Mean SSM SWV was reported from the software region of interest or calculated from sample volumes. Exclusion criteria included history of rotator cuff repair and non-target measurements on bone or peribursal fat. Qualitative tendon pathology grading was as follows: 1=normal or mild tendinosis without tear, 2=moderate or severe tendinosis without tear or mild tendinosis with low-grade partial tear, 3=partial tear with at least moderate tendinosis, and 4=full-thickness tear. All patients demonstrated normal grayscale appearance of the SSM, without evidence of fatty atrophy. Pearson and Spearman rank correlations were used for statistical analysis. Results: No statistically significant correlation was found between mean SSM SWV and mean PSST, DSST, or overall tendon SWV (R=0.14, p=0.396; R=0.04, p=0.832; R=0.06, p=0.731, respectively). There was no statistically significant correlation between SSM SWV and tendon grade (R=0.13, p=0.435). Mean PSST, DSST, and overall tendon SWV demonstrated weak negative correlation with qualitative tendon grade (R=-0.22, p=0.183; R=-0.32, p=0.054; R=-0.30, p=0.045, respectively). Conclusion: Supraspinatus muscle SWV does not appear to vary with quantitative tendon SWVor qualitative tendon grading. Aweak negative correlation between supraspinatus tendon SWV and qualitative tendon grade is compatible with tendon softening with progressive tendinopathy

Purpose: Assess the impact of MR pelvic and lumbosacral neuorgraphy on ultrasound-guided pelvic perineural injections. Materials and Methods: A retrospective review of all ultrasound-guided pelvic perineural injections with prior MR pelvic and/or lumbosacral neurographic imaging over a 5-year period was performed. Demographics, presence of structural pathology on imaging, and immediate and interval pain relief was recorded. Results: 30 total injections were performed among 20 patients accounting for multiple injections in a single visit or multiple visits [mean age at injection: 52.03 (range 23-77), female (n= 24, 80%) male (n=6; 20%)]. In 24 cases a combination of steroid and anesthetic solution was administered. In the remaining 6 cases, only anesthetic solution was administered. Most commonly, injections involved the sciatic nerve (n = 21; 70%). Other injections in our series include pudendal (n=5, 16.7%), genitofemoral (n=2; 6.7%), lateral femoral cutaneous (n=1, 3.3%) and ilioinguinal (n= 1, 3.3%) nerves. Concurrent therapeutic procedures were performed in 10 cases (33%). Pre-procedure MR imaging revealed structural abnormality of the nerve or adjacent soft tissues in 11 of 22 MRIs performed amongst the 20 patients (50%). Pre-procedure ultrasound revealed structural abnormalities associated with the nerve in 9 cases of 19 cases that had complete documentation (47%). Of 26 injections with complete documentation, immediate improvement of symptoms was reported in 22 cases (85%). The remaining 4 cases either began with no pain (n=3), or reported no change in symptoms (n=1). Variable degrees of long-term symptom relief was achieved in 4 injections out of 11 steroid injections for which follow-up was available (37%). Conclusion: Ultrasound-guided perineural injections can be performed for treatment of a variety of pelvic neuropathies. MR imaging prior to sonographic intervention demonstrated an abnormality in nearly half of cases, and is a useful tool to appropriately target perineural injections