Mentorship in academic musculoskeletal radiology: perspectives from a junior faculty member

The first years of an academic musculoskeletal (MSK) faculty position are a time of transition for the junior faculty member, who must rapidly adjust to new clinical, academic, operational, and professional responsibilities. Mentoring has a critical role in helping the faculty member to thrive in these early years. Establishing clear communication, trust, and expectations can set the foundation for an effective mentoring relationship. Junior faculty members ideally would have multiple mentors with different areas of expertise, including mentors of all roles in MSK radiology but also in other radiology divisions and other departments. Private practice MSK radiologists can also benefit from mentorship. Barriers to mentoring in MSK radiology include overall smaller division sizes, a newer and smaller field on a national level, and the increase in clinical volume and remote work that results in less face-to-face interaction. Despite the challenges, both junior MSK faculty members and their mentors can benefit greatly from strong mentoring connections.

High-resolution ultrasound and MRI in the evaluation of pectoralis major injuries

The pectoralis major muscle is the largest muscle of the anterior chest wall. The primary function of the muscle is to adduct and internally rotate the arm at the shoulder. The pectoralis major muscle is broken down into two main components or "heads" based upon muscle fiber origin: clavicular and sternal. Pectoralis major muscle injury results from direct trauma or indirect force overload. The inferior sternal head fibers are the most commonly torn. The pectoralis major tendon most commonly is torn at the humeral insertion. Magnetic resonance imaging and high-resolution ultrasound have value in diagnosing pectoralis major muscle injury and help guide clinical and surgical management. Non-operative versus operative management of pectoralis major tears is dependent upon accurate diagnosis of tear location and severity on imaging. Operative management is recommended for tears at the humeral insertion and for musculotendinous junction tears with severe cosmetic/functional deformity. The indications for surgical intervention have been further expanded to complete intra-tendinous tears, defined as the mid-tendon substance between the myotendinous junction and humeral insertion, and those located at the sternal head/posterior lamina. This paper reviews normal pectoralis major anatomy and the spectrum of injury on magnetic resonance imaging and ultrasound. The importance of regional anatomical landmarks in assessing for pectoralis major muscle injury will be described. Other pathologies, such as tumor and infection, can also affect the pectoralis major muscle and key imaging features will be discussed to help differentiate these entities. Operative and non-operative management of pectoralis major muscle injury is described with examples of pectoralis major repair on post-operative imaging.

Conventional Chondrosarcoma of the Rib Cage and Sternum: Clinicopathological and Molecular Analysis of 27 Patients Treated at a Single Institution

Conventional chondrosarcoma of the chest wall is rare, accounting for 15% of cases. Our purpose was to document clinicopathological, imaging and outcome results from a novel set of chest wall chondrosarcomas, and to analyze for <I>IDH</I> mutations and novel molecular alterations. Gross and microscopic pathology, imaging and clinical charts were reviewed. Targeted next-generation sequencing was performed to identify somatic mutations and copy number alterations. The cohort consisted of 27 patients: 16 men and 11 women (mean age 51 years; range 23-76). Palpable mass was the most common presentation. Five were discovered incidentally. Among 20 tumors with complete imaging, 15 arose from a rib and 5 from the sternum. Seven rib tumors were central/intramedullary, 5 were periosteal, 2 were secondary peripheral chondrosarcomas, and one was indeterminate. Among sternal tumors, 4 were central/intramedullary and one was periosteal. Half the periosteal tumors arose from the costochondral junctional cartilage (CCJ). Periosteal chondrosarcomas were sometimes mistaken for extraskeletal masses on initial clinical or radiological examinations. Fifty-nine percent of all tumors were grade 1 and 41% were grade 2. None were dedifferentiated chondrosarcomas. Heterozygous <I>IDH1</I> mutation was detected in one tumor and heterozygous <I>RAD50</I> mutation in another. Local recurrence(s) happened in 41% and metastasis in 41%. Grade had strong association with local recurrence (25% grade 1 vs. 64% grade 2 [p=0.0447]), metastatic recurrence (19% grade 1 vs. 73% grade 2 [p=0.0058]), and survival. Although chest wall chondrosarcomas share morphologic and molecular features with other chondrosarcomas, there is a much higher incidence of periosteal chondrosarcomas. <I>IDH</I> mutant tumors are uncommon. Early diagnosis and margin-negative resection is treatment of choice since chondrosarcomas are chemo- and radioresistant.

Ultrasound of myxofibrosarcoma

The ultrasound appearance of myxofibrosarcoma is highly variable corresponding to its variable and at times heterogeneous histopathologic appearance. Myxofibrosarcomas may mimic a benign process and the infiltrative tumor margins may be difficult to precisely delineate on ultrasound imaging. These tumor characteristics pose a diagnostic challenge on ultrasound evaluation. The radiologist should be aware of the variable morphologic presentation and infiltrative nature of myxofibrosarcoma and the limitations of ultrasound in the initial diagnosis, biopsy guidance, and post-surgical follow-up of this tumor.

Imaging the intermuscular septum in the context of ulnar neuropathy

Impingement/entrapment of the ulnar nerve by the intermuscular septum at the distal arm is a common cause of recurrent or recalcitrant ulnar neuropathy following ulnar nerve decompression or anterior transposition. Primary entrapment/impingement of the ulnar nerve along the intermuscular septum may also occur. Evaluation with both ultrasound (US) and MRI can identify entrapment of the ulnar nerve at the intermuscular septum, while dynamic assessment with US can also identify dynamic subluxation of the ulnar nerve over the intermuscular septum.

Untreated plasmacytoma of bone containing macroscopic intralesional fat and mimicking intraosseous lipoma: A case report and review of the literature

Solitary plasmacytoma is a rare form of plasma cell neoplasm defined by local neoplastic accumulation of monoclonal plasma cells in the absence of systemic proliferative plasma cell disease. In this case report, a 65-year-old female with remote past medical history of papillary thyroid cancer presented with shoulder pain and radiographs showing an aggressive osteolytic lesion presumed to represent an osseous metastasis. The subsequent MRI and CT examinations demonstrated diffuse intralesional macroscopic fat without a nonlipogenic soft tissue component or focal, nodular mass-like enhancement. The presence of macroscopic fat in an untreated osseous lesion suggested a benign lesion with the favored diagnosis an intraosseous lipoma with non-displaced pathological fracture. Therefore, the decision was made to forego image-guided percutaneous biopsy and instead proceed directly to open surgical biopsy and partial distal claviculectomy. Pathology of the resected specimen showed focally dense infiltration of plasma cells within the marrow space and scant hematopoiesis compatible with a plasma cell neoplasm. To the best of our knowledge, this is first case report of solitary plasmacytoma of bone, or any untreated plasma cell neoplasm, containing macroscopic fat upon imaging. The decision to forego image-guided percutaneous biopsy had significant treatment implications as the primary therapy for patients with SPB is not surgical, but localized radiation therapy. Based on this case, solitary plasmacytoma of bone may be included as one of the rare fat containing malignant bone lesions and imaging guided percutaneous biopsy should be considered in symptomatic fat-containing bone lesions.

Imaging appearance following surgical decompression of the ulnar nerve

Ulnar neuropathy at the elbow is the second most common entrapment neuropathy of the upper extremity. Yet, there is a paucity of literature focusing on the imaging appearance following surgical decompression of the ulnar nerve at the elbow. Diagnostic imaging studies obtained after surgical decompression at The University of Michigan were reviewed and imaging findings were documented. We aim to describe the various techniques of ulnar nerve decompression and corresponding post-operative appearance on imaging. Potential complications following decompression will also be described with imaging and clinical correlation of recalcitrant ulnar neuropathy. It is important for the radiologist who performs MRI or ultrasound of the elbow to be aware of the various ulnar nerve decompression procedures. This knowledge will facilitate rapid and accurate diagnosis of normal and abnormal appearance of the ulnar nerve in this context.

Imaging appearance of well-differentiated liposarcomas with myxoid stroma

OBJECTIVE

Describe the imaging appearance of well-differentiated liposarcoma with myxoid stroma (WDLMS) and correlate with histopathology.

MATERIALS AND METHODS

A keyword search of the institution medical records was performed from 1 January 2000 to 30 June 2017. The histopathology slides of cases identified in this fashion were then reviewed by a pathologist. Additional cases were prospectively collected from extramural referrals and tumor boards. Diagnostic imaging studies of pathologically proven cases of WDLMS were then reviewed in consensus and correlated with pathology.

RESULTS

Ten cases of pathologically proven WDLMS were identified (7 men, 3 women, ages 26-81). Tumor location included the retroperitoneum (n = 5), thigh (n = 4), and the shin (n = 1). Nine patients had macroscopic fat on imaging. The nonlipomatous components had a variable appearance, including septal, nodular, and lacelike patterns. Two cases included two distinct areas that were predominantly myxoid or lipomatous ("bi-morphic"). One tumor had no macroscopic fat on imaging. On CT, the nonlipomatous nodular components were hypodense/had hypodense areas. On MRI, the nodular components had intermediate/bright T2W signal. Interval nonlipomatous nodular growth was identified in 3 cases.

CONCLUSION

WDLMS may present on imaging as a mass with variable morphology and amounts of nonlipomatous components. Histopathological diagnosis of WDLMS is challenging and imaging correlation may be helpful, as this tumor may have ≥50% fatty volume, may have a myxoid nodular component or bi-morphic appearance, or may be located in the retroperitoneum, features that are unusual for myxoid liposarcoma. WDLMS with a nodular component cannot be distinguished from dedifferentiated liposarcoma based on imaging alone.

Creating Three-dimensional Printed Models of Acetabular Fractures for Use as Educational Tools

Acetabular fractures are frequently encountered in some clinical practices, and the precise classification of these fractures greatly influences treatments and outcomes. The authors identified the need for an educational aid when teaching acetabular fracture classifications, given the complex spatial anatomy and the nonintuitive classification system that is commonly used. Three-dimensional ( 3D three-dimensional ) printing is an evolving technique that has applications as an educational aid, providing the student with a tangible object to interact with and learn from. In this article, the authors review their experience creating 3D three-dimensional printed models of the hip for educational purposes. Their goal was to create 3D three-dimensional printed models for use as educational aids when teaching acetabular fracture classifications. Complex cases involving a combination of fracture types, subtle nondisplaced fractures, and/or fractures with associated osteopenia or artifacts were excluded. The selected computed tomographic (CT) scans were loaded into a medical 3D three-dimensional volume-rendering program, and a 3D three-dimensional volumetric model was created. Standard Tessellation Language ( STL Standard Tessellation Language ) files were then exported to STL Standard Tessellation Language model-editing software and edited to retain only the involved hemipelvis. In some cases, the proximal femur and ipsilateral hemisacrum may be included to emphasize hip alignment or disruption of the force transfer. Displaced fracture fragments can be printed as separate segments or a single unit after the addition of struts. Printing was performed by using an additive manufacturing principle, with approximately 36-48 hours needed for printing, postprocessing, and drying. The cost to print a 1:1 scale model was approximately $100-$200, depending on the amount of plastic material used. These models can then be painted according to the two-column theory regarding acetabular fractures. ^©RSNA, 2017.

Ultrasound evaluation of bursae: anatomy and pathological appearances

A bursa is an extra-articular sac that may communicate with a joint and functions to decrease friction between tendons and either bone or skin. Bursae can be classified as native and non-native (adventitious) bursae. The native bursae are lined with a synovial membrane and occur at predictable anatomical sites; knowledge of these normal structures can help distinguish them from other pathological entities. An adventitious bursa can form at sites of friction rather than at predictable anatomical sites, but otherwise have imaging features similar to native bursae. Bursal distention can occur from many pathological processes, most commonly resulting from chronic overuse injury. When imaging bursal pathological conditions, there is often an overlap of imaging findings, regardless of the cause. In general, ultrasound of a distended bursa reveals a fluid collection with either simple anechoic or more complex hypoechoic fluid. Bursal distention is characteristically unilocular and compressible, unlike other structures such as ganglion cysts, which are usually multilocular and non-compressible. This article reviews the anatomical locations of common bursae and shows pathological examples using ultrasound. Knowledge of typical locations and imaging appearances of bursae can aid in narrowing the differential diagnosis and guiding further management and treatment decisions.

Imaging Nerve Pathology of the Knee: Magnetic Resonance Imaging and Ultrasound

Peripheral neuropathies are not uncommon, and the diagnostic evaluation includes a clinical assessment and electrophysiologic studies as well as diagnostic imaging. Magnetic resonance imaging (MRI) and high-resolution ultrasound (HRUS) are of special importance in providing the surgeon with information in the context of nerve trauma, entrapment, and nerve involvement by tumors. Peripheral neuropathy about the knee can occur in the context of associated knee pathology such as trauma, as part of a systemic disease, or as an isolated finding. In this review, we discuss the role of MRI and HRUS in the evaluation of peripheral neuropathy and present imaging examples of peripheral neuropathy involving the knee.

US of the Peripheral Nerves of the Upper Extremity: A Landmark Approach

Ultrasonography (US) has become a first-line modality for the evaluation of the peripheral nerves of the upper extremity. The benefits of US over magnetic resonance (MR) imaging include higher soft-tissue resolution, cost effectiveness, portability, real-time and dynamic imaging, and the ability to scan an entire extremity quickly and efficiently. US can be performed on patients who are not eligible for MR imaging. Metallic implant artifacts are usually not problematic. US has been shown to have equal specificity and greater sensitivity than MR imaging in the evaluation of peripheral nerves. Any abnormal findings can be easily compared with the contralateral side. The published literature has shown that US has demonstrated clinical utility in patients with suspected peripheral nerve disease by guiding diagnostic and therapeutic decisions as well as by confirming electrodiagnostic findings. Common indications for upper extremity peripheral nerve US are the evaluation for injury due to penetrating trauma, entrapment by scar tissue, and tumor. US of the upper extremity is most commonly performed to evaluate carpal and cubital tunnel syndrome. It is important for the radiologist or sonographer to have a detailed knowledge of anatomy and specific anatomic landmarks for each nerve to efficiently and accurately perform an examination. The goal of this article is to introduce readers to the basics of US of the peripheral nerves of the upper extremity with a focus on the median, ulnar, and radial nerves. Common sites of disease and the location of important anatomic landmarks will be reviewed.

Myxoinflammatory fibroblastic sarcoma: spectrum of disease and imaging presentation

OBJECTIVES

To describe the imaging findings of a series of myxoinflammatory fibroblastic sarcomas (MFSs) from our institution, including a case of dedifferentiated MFS and two cases with areas of high-grade tumor, in addition to typical cases of low-grade tumor. To correlate the imaging findings with the pathologic features of these tumors.

SUBJECTS AND METHODS

IRB approval was obtained. Retrospective search of the pathology database at our institution from 2000 to 2015 identified seven cases of MFS with available imaging. Imaging, pathology, and clinical data were reviewed.

RESULTS

Unlike the majority of well-differentiated tumors in our series (four cases), one tumor showed dedifferentiation and two cases had areas of high-grade tumor. The dedifferentiated tumor showed peripheral post-contrast enhancement. One case with a substantial high-grade component showed osseous destruction and peripheral enhancement in the high-grade area, while the low-grade component enhanced diffusely. The second case had a small high-grade area and showed diffuse enhancement. All three of these cases had non-acral locations and lacked association with a tendon. The four cases of low-grade MFS demonstrated diffuse enhancement, were located in the distal extremities, and were associated with a tendon.

CONCLUSION

The imaging findings of dedifferentiated and high-grade MFS differ from the more typical low-grade tumors in that they have nonenhancing areas, a non-acral location, lack association with a tendon, and may involve bone. The radiologist should be aware that MFS represents a spectrum that includes low-grade tumors, tumors with high-grade areas, and tumors with dedifferentiation and that this spectrum presents with differing imaging features.

US of the Peripheral Nerves of the Lower Extremity: A Landmark Approach

Ultrasonography (US) is commonly used to assess the peripheral nerves of the lower extremity because of its many advantages over magnetic resonance (MR) imaging. The most obvious advantages over MR imaging are superior soft-tissue resolution, low cost, portability, lack of magnetic susceptibility artifact, and the ability to image patients who cannot undergo MR imaging. US has been shown to have equal specificity and greater sensitivity than MR imaging in the evaluation of peripheral nerves. Additional benefits are the capability of real-time and dynamic imaging, and the ability to scan an entire extremity quickly without the need for a patient to lie motionless for long periods of time, as with MR imaging. Any abnormal findings can be easily compared against the contralateral side. Published literature has shown that US has clinical utility in patients suspected of having peripheral nerve disease: US can be used to guide diagnostic and therapeutic decisions, as well as help confirm electrodiagnostic findings. Common indications for lower extremity peripheral nerve US are the evaluation for injury due to penetrating trauma, entrapment by scar tissue, or tumor. To confidently perform US of the peripheral nerves of the lower extremity, it is important to gain a thorough knowledge of anatomic landmarks and the course of each nerve. Readers who may not be familiar with US will be introduced to the basics of scanning the peripheral nerves of the lower extremity. Important anatomic landmarks and common sites of injury and entrapment will be reviewed.

Prevalence of the acetabular sublabral sulcus at MR arthrography in patients under 17 years of age: does it exist?

PURPOSE

To retrospectively determine characteristics of contrast-filled acetabular labral clefts in patients under the age of 17 years at MR arthrography (Mra) correlated with arthroscopy, which may impact the thinking regarding the existence of a sublabral sulcus.

MATERIALS AND METHODS

After IRB approval, 41 patients under the age of 17 who had MRa were identified. The following observations of contrast-filled clefts were assessed: (1) presence/absence, (2) location, (3) depth, (4) abnormal signal within the labrum and (5) shape (linear, gaping, complex). Fisher's exact and the Wilcoxon matched-pairs signed-rank test were performed. Interreader agreement was calculated with Cohen's k.

RESULTS

Reader 1 found clefts in 41 %. Depth was less than half in 6%, more than half in 65% and full thickness in 29%. Shape was linear in 53%, gaping in 18% and complex in 29%. Signal changes occurred in 88%. Reader 2 found clefts in 29%. Depth was less than half in 17%, more than half in 58% and full thickness in 25%. Shape was linear in 50%, gaping in 42% and complex in 17%. Signal changes occurred in 50%. None of the clefts fulfilled the criteria for a sublabral sulcus at MRa and arthroscopy.

CONCLUSION

None of the clefts found in our subjects under the age of 17 years met the MRa and arthroscopy criteria for a sublabral sulcus, which supports the theory that such clefts represent labral tears.

Peer support of a faculty "writers' circle" increases confidence and productivity in generating scholarship

RATIONALE AND OBJECTIVES

Publishing is critical for academic medicine career advancement. Rejection of manuscripts can be demoralizing. Obstacles faced by clinical faculty may include lack of time, confidence, and optimal writing practices. This study describes the development and evaluation of a peer-writing group, informed by theory and research on faculty development and writing.

MATERIALS AND METHODS

Five clinical-track radiology faculty members formed a "Writers' Circle" to promote scholarly productivity and reflection on writing practices. Members decided to work with previously rejected manuscripts. After members' initial meeting, interactions were informal, face to face during clinical work, and online. After the first 6 months, an anonymous survey asked members about the status of articles and evaluations of the writing group.

RESULTS

Ten previously rejected articles, at least one from each member, were submitted to the Circle. In 6 months, four manuscripts were accepted for publication, five were in active revision, and one was withdrawn. All participants (100%) characterized the program as worth their time, increasing their motivation to write, their opportunities to support scholarly productivity of colleagues, and their confidence in generating scholarship.

CONCLUSIONS

Peer-support writing groups can facilitate the pooling of expertise and the exchange of recommended writing practices. Our peer-support group increased scholarly productivity and provided a collegial approach to academic writing.

MR imaging of the pelvis: a guide to incidental musculoskeletal findings for abdominal radiologists

Occasionally patients who undergo magnetic resonance imaging for presumed pelvic disease demonstrate unexpected musculoskeletal imaging findings in the imaged field. Such incidental findings can be challenging to the abdominal radiologist, who may not be familiar with their appearance or know the appropriate diagnostic considerations. Findings can include both normal and abnormal bone marrow, osseous abnormalities such as Paget's disease, avascular necrosis, osteomyelitis, stress and insufficiency fractures, and athletic pubalgia, benign neoplasms such as enchondroma and bone island, malignant processes such as metastasis and chondrosarcoma, soft tissue processes such as abscess, nerve-related tumors, and chordoma, joint- and bursal-related processes such as sacroiliitis, iliopsoas bursitis, greater trochanteric pain syndrome, and labral tears, and iatrogenic processes such as bone graft or bone biopsy. Though not all-encompassing, this essay will help abdominal radiologists to identify and describe this variety of pelvic musculoskeletal conditions, understand key radiologic findings, and synthesize a differential diagnosis when appropriate.

Capsular laxity of the hip: findings at magnetic resonance arthrography

PURPOSE

The purpose of this study was to retrospectively investigate magnetic resonance (MR) arthrography imaging findings associated with capsular laxity of the hip joint found at surgery.

METHODS

After institutional review board approval, 27 patients who had arthroscopy reports that described the presence or absence of capsular laxity of the hip joint were identified over a 2-year period. Preoperative MR images were retrospectively reviewed by 2 blinded radiologists. The following observations were recorded: (1) thickness, signal intensity, and defects of the anterior joint capsule; (2) thickness and signal intensity of the zona orbicularis; (3) width of the anterior and posterior joint recesses at the level of the femoral head; (4) presence of synovitis in the anterior joint recess; and (5) volume of intra-articular contrast and degree of hip rotation. Intrarater and inter-rater agreement was assessed.

RESULTS

Of the 27 patients, 17 were positive and 10 were negative for hip joint laxity at arthroscopy. The mean thickness of the anterior hip capsule was significantly different (P = .0043), measuring 2.5 mm (95% confidence interval [CI], 2.3 to 2.8 mm) in those with hip laxity and 3.3 mm (95% CI, 2.8 to 3.8 mm) in those without laxity. The mean width of the anterior joint recess was 5.8 mm (95% CI, 5.4 to 6.3 mm) in those with laxity and 3.6 mm (95% CI, 3.3 to 3.9 mm) in those without laxity and was significantly different (P < .0001). No other variables were considered useful because of a lack of significant differences between the 2 patient groups or low inter-rater agreement.

CONCLUSIONS

On the basis of 95% CIs, hip joint laxity at MR arthrography is associated with widening of the anterior hip joint recess (>5 mm) and thinning of the adjacent joint capsule (<3 mm) lateral to the zona orbicularis.

Ultrasound and MRI of the peroneal tendons and associated pathology

Lateral ankle pain is common with overuse and sports-related injuries and may cause considerable morbidity. The differential diagnosis of lateral ankle pain is extensive. Disorders of the peroneal tendons should be an important consideration during interpretation of a routine ankle magnetic resonance imaging (MRI) or ultrasound (US). This article presents a review of the common causes of peroneal tendon pathology with particular reference to anatomy, US, and MRI features. The importance of dynamic evaluation with ultrasound is also emphasized.

Intra- and inter-rater reliability of the detection of tears of the supraspinatus central tendon on MRI by shoulder surgeons

BACKGROUND

The purpose of this study was to determine the intra- and inter-rater reliability of detecting full- and partial-thickness tears of the supraspinatus intramuscular central tendon on magnetic resonance imaging (MRI) by orthopaedic shoulder surgeons. Full-thickness tears of this tendon have previously been associated with the failure of nonsurgical management of rotator cuff tears.

METHODS

Shoulder MRIs from 40 patients entered into a prospective rotator cuff disease database were independently reviewed by two musculoskeletal (MSK) radiologists in order to determine if there was a partial- or full-thickness tear of the supraspinatus central tendon. The MRIs were randomly sorted and distributed to 16 fellowship-trained shoulder surgeons. The surgeons then similarly diagnosed each patient. After a 1-month interval, surgeons repeated the evaluation with the same set of randomly reordered MRIs. Surgeon intra- and inter-rater reliability was determined with the kappa statistic. Agreement and inter-rater reliability were also determined between the shoulder surgeons and MSK radiologists.

RESULTS

For full-thickness tears, the intra-rater reliability was excellent (0.86 ± 0.1, 95% confidence interval (CI): 0.81, 0.91) and the agreement was 93.4% ± 4.6, 95% CI: 91.1, 95.8. Inter-rater reliability for both rounds was also excellent (0.77 and 0.74). The agreement between the shoulder surgeons and MSK radiologists was 92.9% ± 3.9, 95% CI: 90.9, 94.9, and the kappa was 0.85 ± 0.08, 95% CI: 0.81, 0.89. Including partial-thickness tears resulted in agreement of 65-92% and kappa values of 0.59-0.72.

CONCLUSION

The reliability for the MRI detection of full thickness tears of the supraspinatus central tendon among shoulder surgeons and between shoulder surgeons and MSK radiologists was excellent.

Ultrasonography of the shoulder with arthroscopic correlation

Ultrasonography is a well-established and widely accepted modality for the evaluation of rotator cuff tears and injury to the biceps brachii tendon. Ultrasonography and magnetic resonance imaging have comparable sensitivity and specificity for diagnosing both full-thickness and partial-thickness rotator cuff tears. This article addresses the ultrasonographic diagnosis of abnormalities of the rotator cuff, rotator interval, and biceps brachii, with magnetic resonance imaging and arthroscopic correlation. Characteristic ultrasonographic findings as well as imaging pitfalls are reviewed.

Imaging review of skeletal tumors of the pelvis--part I: benign tumors of the pelvis

The osseous pelvis is a well-recognized site of origin of numerous primary and secondary musculoskeletal tumors. The radiologic evaluation of a pelvic lesion often begins with the plain film and proceeds to computed tomography (CT), or magnetic resonance imaging (MRI) and possibly biopsy. Each of these modalities, with inherent advantages and disadvantages, has a role in the workup of pelvic osseous masses. Clinical history and imaging characteristics can significantly narrow the broad differential diagnosis for osseous pelvic lesions. The purpose of this review is to familiarize the radiologist with the presentation and appearance of some of the common benign neoplasms of the osseous pelvis and share our experience and approach in diagnosing these lesions.

Paralabral cysts of the hip: sonographic evaluation with magnetic resonance arthrographic correlation

This retrospective study demonstrates the sonographic appearance paralabral cysts of the hip with magnetic resonance (MR) arthrography as the reference standard. Consensus review by 2 musculoskeletal radiologists was used to assess the paralabral cysts and determine their characteristics. The 3 paralabral cysts seen on sonography and confirmed with MR arthrography in this study were anechoic or hypoechoic, lobulated, and filled with contrast on MR imaging. A labral tear was also noted in all cases on both sonography and MR arthrography. Sonographic assessment for an anterior hip paralabral cyst and labral tear may be of diagnostic benefit.

The rotator interval and long head biceps tendon: anatomy, function, pathology, and magnetic resonance imaging

The rotator interval is an anatomically defined triangular area located between the coracoid process, the superior aspect of the subscapularis, and the anterior aspect of the supraspinatus. It is widely accepted that the rotator interval structures fulfill a role in biomechanics and pathology of the glenohumeral joint and long head biceps tendon. However, there is ongoing debate regarding the biomechanical details and the indications for treatment. A better understanding of rotator interval anatomy and function will lead to improved treatment of rotator interval abnormalities, and guide the indications for imaging and surgical intervention.

Sonography of partial-thickness tears of the distal triceps brachii tendon

OBJECTIVES

The purpose of this study was to retrospectively characterize the sonographic appearance of partial-thickness distal triceps brachii tendon tears.

METHODS

After Institutional Review Board approval, sonographic records were searched for patients who had an unequivocal partial-thickness triceps tendon tear at surgery or magnetic resonance imaging. Sonograms were retrospectively characterized for tendon discontinuity of the superficial or deep layers, tendon retraction, osseous fracture fragments, and joint effusion. Imaging findings were then compared with clinical, imaging, and surgical results.

RESULTS

Five patients had a partial-thickness distal triceps brachii tendon tear at surgery (n = 4) or magnetic resonance imaging (n = 1). All cases only involved the superficial tendon layer (combined long and lateral heads) with retraction of a fractured olecranon enthesophyte fragment. The deep tendon layer (medial head) was intact in all cases with no joint effusion.

CONCLUSIONS

Partial-thickness distal triceps brachii tendon tears have a characteristic appearance with selective superficial tendon retraction and olecranon enthesophyte avulsion fracture.

Usefulness of the twinkling artifact in identifying implanted mesh after inguinal hernia repair

OBJECTIVES

Implanted mesh for inguinal hernia repair is often difficult to visualize with gray scale sonography and may present without the knowledge of the sonographer. We sought to evaluate the utility of the twinkling artifact produced by inguinal mesh to assist in mesh identification.

METHODS

Two reviewers evaluated focused sonographic examinations of 44 inguinal regions, 24 of which had implanted inguinal mesh. The sonographic examinations consisted of static gray scale and color Doppler images with both linear and curvilinear array transducers. The presence of the twinkling artifact and visibility of the mesh were graded on a 4-point visibility scale.

RESULTS

Inguinal mesh was not easily identified on gray scale imaging using either the curvilinear array (P = .5) or linear array (P = .5) transducer. The mesh was definitely seen in 3 of 24 inguinal regions using the linear array transducer and 2 of 24 inguinal regions using the curvilinear array transducer. In 79% of inguinal regions with mesh, the twinkling artifact was produced with the curvilinear array transducer only. The artifact was not elicited when using the linear array transducer. With the use of the curvilinear array transducer and the presence of the twinkling artifact, there was a significant chance of correctly identifying the presence of mesh (P < .005) in the entire study group.

CONCLUSIONS

Standard gray scale imaging alone is not reliable when identifying inguinal mesh. The twinkling artifact was present in 79% of inguinal regions with mesh when evaluated with a low-frequency curvilinear array transducer.

The subscapularis: anatomy, injury, and imaging

The subscapularis is the largest and most powerful of the rotator cuff muscles and fulfills an important role in glenohumeral movement and stability. The spectrum and implications of subscapularis muscle or tendon injury differ from injury to other rotator cuff components because of its unique structure and function. Diagnosing subscapularis injury is clinically difficult and assessment of subscapularis integrity may be limited during arthroscopy or open surgery. Diagnostic imaging plays an important part in diagnosing and evaluating the extent of subscapularis injury. The radiologist should be aware of the anatomy of the subscapularis, the variations in muscle or tendon injury, and the potential implications for treatment and prognosis.

MRI interpretation proficiency of musculoskeletal fellows in training

RATIONALE AND OBJECTIVES

The aim of this study was to evaluate the magnetic resonance imaging (MRI) interpretation proficiency of musculoskeletal fellows in training.

MATERIALS AND METHODS

Between July 2003 and June 2007, 14 musculoskeletal fellows were independently tested with 20 MRI studies of the knee and shoulder at four separate time points during their fellowship years. Trends in true-positive and false-positive interpretation results were evaluated. Fellows who completed their residencies at the fellowship institution (internal fellows) were compared with those from other residencies (external fellows).

RESULTS

There was a significant improvement in proficiency between the initial and final (9-month) evaluations (P < .0001). At the initial evaluation, there was a mean of 52.8% (41.7 of 79) true-positive results (range, 32-51); at 9 months, there was a mean of 71.0% (56.1 of 79; range, 40-72). The number of false-positive results also declined during this time period from a mean of 8.1 (range, 2-13) at initial evaluation to 4.7 (range, 2-8) at 9 months (P < .001). External fellows had more incorrect diagnoses initially but showed greater improvement than internal fellows at 9 months.

CONCLUSION

Fellows continued to improve their MRI interpretation skills throughout the first 9 months of their fellowships. External fellows were slightly less proficient at the start of their fellowships but slightly more proficient at 9 months compared to internal fellows.

Sonographic evaluation of Lisfranc ligament injuries

OBJECTIVE

This study characterized the sonographic appearances of Lisfranc injuries.

METHODS

Sonography reports (2000-2007) were searched for "Lisfranc," resulting in 10 patients. Sonographic images of affected and asymptomatic contralateral feet were reviewed, recording the thickness of the dorsal ligament between the first (medial) cuneiform (C1) and second metatarsal (M2) ligaments, distance between C1 and M2, and change in this distance with weight bearing, hyperemia, and fractures. Correlations were made to clinical, surgical, and other imaging findings.

RESULTS

In 5 asymptomatic feet, the dorsal C1-M2 ligament was 0.9 to 1.2 mm thick, and the C1-M2 distance was 0.5 to 1 mm. Of the symptomatic feet, 1 group (n=3) had normal sonographic findings (thickness, 0.9-1.1 mm; distance, 0.6-0.7 mm; all had normal radiographic findings and follow-up, and 1 had normal magnetic resonance imaging [MRI] findings). Another group (n=3) had abnormal hypoechogenicity and thickening of the dorsal C1-M2 ligament (1.4-2.3 mm), a normal C1-M2 distance (0.6-0.7 mm), and no widening with weight bearing (1 of 1), consistent with a ligament sprain (1 had normal computed tomographic [CT] findings, and all had uneventful follow-up). The third group (n=4) had nonvisualization of the dorsal C1-M2 ligament, an increased C1-M2 distance of 2.5 to 3.1 mm, and further widening with weight bearing (3 of 4) from Lisfranc ligament disruption (shown at surgery in 2, MRI in 1, and CT in 1).

CONCLUSIONS

Nonvisualization of the dorsal C1-M2 ligament and a C1-M2 distance of 2.5 mm or greater were indirect signs of a Lisfranc ligament tear. Dynamic evaluation with weight bearing showed widening of the space between C1 and M2.

Sonographic surface localization of subcutaneous foreign bodies and masses

We report a sonographic technique of skin marking of the projection of nonpalpable subcutaneous foreign bodies and masses using a paperclip. Localization and marking of the overlying skin assists in preoperative planning and further management.

Sonography of fat necrosis involving the extremity and torso with magnetic resonance imaging and histologic correlation

OBJECTIVE

The purpose of this study was to describe the sonographic appearance of pathologically proven isolated fat necrosis involving the extremities or torso with magnetic resonance imaging (MRI) correlation.

METHODS

A query of the Department of Pathology database at our institution for the diagnosis of fat necrosis resulted in 1539 cases. Review of the cases and medical records excluded cases without sonographic imaging, those involving the breast, and those within or adjacent to a primary process, including masses or prior surgery, which resulted in a total of 5 cases of primary fat necrosis, 2 of which were evaluated with MRI. Sonograms were reviewed by 2 musculoskeletal radiologists and characterized with regard to location, echogenicity, shadowing, posterior through-transmission, a hypoechoic rim or halo, definition of borders, homogeneity, a mass effect, and vascularity. The patient medical records, histologic results, and MRI findings were also reviewed.

RESULTS

Of the 5 cases of isolated fat necrosis, 2 involved the torso and 3 the lower extremities. On sonography, all were located in the subcutaneous fat; 2 were isoechoic; 3 were hyperechoic; 2 had a hypoechoic halo; none showed shadowing or posterior through-transmission; 2 were well defined; 3 were masslike; 4 were heterogeneous; and 2 showed increased flow on color or power Doppler imaging. Magnetic resonance imaging showed an intermediate signal and either diffuse or ring enhancement.

CONCLUSIONS

Isolated fat necrosis of the extremities and torso had 2 sonographic appearances, which included a well-defined isoechoic mass with a hypoechoic halo and a poorly defined hyperechoic region in the subcutaneous fat.

Sonography of Morel-Lavallee lesions

OBJECTIVE

The purpose of this series was to retrospectively characterize the sonographic appearance of posttraumatic Morel-Lavallée lesions.

METHODS

After Institutional Review Board approval was obtained, a search of the radiology information system database with correlation to medical records identified 21 posttraumatic fluid collections of the hip and thigh in 15 patients. Sonographic images were retrospectively reviewed by 1 author to characterize the echogenicity, homogeneity, shape, margins, location, compressibility, and vascularity of the fluid collection. Results were correlated with the age of the fluid collection and aspiration results where possible.

RESULTS

All fluid collections (21/21) were located between the deep fat and fascia, with a shape that was fusiform in 12 (60%) of 20, flat in 5 (25%), and lobular in 3 (15%) (shape not determined in 1 case). Regarding echogenicity, 15 (71%) of the 21 collections were hypoechoic, and 6 (29%) were anechoic; 13 (62%) were heterogeneous, and 8 (38%) were homogeneous. The lobular fluid collections were all less than 2 weeks of age, and the flat fluid collections were all greater than 6 months of age. All homogeneous fluid collections were greater than 8 months of age. There was no relationship between the age of a fluid collection and its echogenicity. Conclusions. Morel-Lavallée lesions had a variable appearance, being more homogeneous and flat or fusiform in shape with a well-defined margin as the lesions aged. All Morel-Lavallée lesions were hypoechoic or anechoic, compressible, and located between the deep fat and overlying fascia.

Abdominal wall hernia mesh repair: sonography of mesh and common complications

OBJECTIVE

The purposes of this study were (1) to review the sonographic in vitro and in vivo appearances of mesh for surgical repair of abdominal wall hernias, (2) to describe sonographic techniques and discuss the limitations of sonography in evaluation of mesh hernia repair, and (3) to illustrate common complications after mesh repair shown with sonography.

METHODS

We identified interesting cases from the musculoskeletal sonographic database as well as from the teaching files of the authors, with surgical or other cross-sectional imaging corroboration.

RESULTS

A compilation of the sonographic appearances of mesh used for anterior abdominal wall and inguinal hernia repair and complications diagnosable by sonography is presented.

CONCLUSIONS

Sonography can be effective for evaluation of mesh and complications after mesh repair of anterior abdominal wall and inguinal hernias.

Lisfranc joint displacement following sequential ligament sectioning

BACKGROUND

There are two primary radiographic patterns of Lisfranc instability, transverse and longitudinal. There is no single diagnostic method with which to consistently confirm the diagnosis of an unstable injury. Our purpose was to define which ligament disruptions produce these two injury patterns and to compare the utility of weight-bearing and stress radiographs for detecting each pattern of instability.

METHODS

Ten fresh-frozen cadaveric lower extremities were dissected to expose the dorsal aspect of the midfoot. Radiographic markers were placed at the base of the second metatarsal and the distal borders of the first and second cuneiforms. The specimens underwent sectioning of the interosseous first cuneiform-second metatarsal (Lisfranc) ligament and were then divided into two groups. The transverse group underwent sectioning of the plantar ligament between the first cuneiform and the second and third metatarsals at the plantar aspect of the second cuneiform-second metatarsal joint, whereas the longitudinal group underwent sectioning of the interosseous ligament between the first and second cuneiforms. Weight-bearing, adduction, and abduction stress radiographs were made before and after each ligament was sectioned. The radiographs were digitized, and displacement was recorded. Instability was defined as >or=2 mm of displacement.

RESULTS

Weight-bearing radiographs made after the Lisfranc (first cuneiform-second metatarsal) ligament alone was sectioned were diagnostic (showed instability) for one of ten specimens. Abduction stress radiographs were diagnostic for two of five specimens, and adduction stress radiographs were diagnostic for zero of five specimens. In the transverse group (sectioning of the plantar ligament between the first cuneiform and the second and third metatarsals), weight-bearing radiographs were diagnostic on the basis of first cuneiform-second metatarsal displacement for one of five specimens but were not diagnostic on the basis of second cuneiform-second metatarsal displacement for any of five specimens. Abduction stress radiographs were diagnostic on the basis of displacement of both the first cuneiform-second metatarsal and the second cuneiform-second metatarsal joints for five of five specimens. In the longitudinal group (sectioning of the interosseous ligament between the first and second cuneiforms), weight-bearing radiographs were diagnostic on the basis of first cuneiform-second metatarsal displacement for one of five specimens and were diagnostic on the basis of displacement between the first and second cuneiforms for one of five specimens. Adduction stress radiographs were diagnostic on the basis of first cuneiform-second metatarsal displacement for one of five specimens and were diagnostic on the basis of displacement between the first and second cuneiforms for four of five specimens.

CONCLUSIONS

Transverse instability required sectioning of both the interosseous first cuneiform-second metatarsal ligament and the plantar ligament between the first cuneiform and the second and third metatarsals. Longitudinal instability required sectioning of both the interosseous first cuneiform-second metatarsal ligament and the interosseous ligament between the first and second cuneiforms. Compared with weight-bearing radiographs, injury-specific manual stress radiographs showed qualitatively greater displacement when used to evaluate both patterns of instability.

Wagner-Meissner neurilemmoma of the right cheek

We report a very rare case of Wagner-Meissner neurilemmoma in the cheek of a 10-year-old boy. The tumor presented as a slowly growing soft tissue swelling. Magnetic resonance imaging disclosed a very infiltrative, 9-cm mass involving the subcutis and deep soft tissues of the right cheek. Microscopically, the tumor was unencapsulated and composed almost entirely of well-formed Wagner-Meissner corpuscles that formed confluent sheets, perivascular cuffs, and individual corpuscles percolating through adipose tissue. Compared with the 3 previous reports, which describe circumscribed, encapsulated tumors in adult patients, this case had distinctive clinicopathologic features never reported: presentation in a pediatric patient, location in the head and neck region, and an infiltrative growth pattern.

Clinical indications for digital imaging in dento-alveolar trauma. Part 1: traumatic injuries

Traumatized teeth present a clinical challenge with regard to their diagnosis, treatment plan, and prognosis. Recent developments in imaging systems have enabled clinicians to visualize structural changes effectively. Computed tomography, magnetic resonance imaging and cone beam computed tomography are among the most commonly used systems for dental and maxillofacial surgery. The purpose of this review is to describe the advantages and disadvantages of each technique and the clinical application for dento-alveolar trauma. Three clinical cases are described to illustrate the potential use of the NewTom 3G for diagnosis and treatment plan of dento-alveolar traumatic injuries.

Characteristic Locations of Inguinal Region and Anterior Abdominal Wall Hernias: Sonographic Appearances and Identification of Clinical Pitfalls

OBJECTIVE

The purpose of this article is to show the typical locations of anterior abdominal wall and inguinal region hernias and to illustrate their sonographic appearances and describe pitfalls in clinical diagnosis of hernias that may be resolved with sonography.

CONCLUSION

Awareness of the expected locations of anterior abdominal wall hernias and potential clinical pitfalls allows an accurate diagnosis of a hernia and helps in differentiating a hernia from other abnormalities.

Magnetic resonance imaging of the rotator cuff interval

The rotator cuff interval (RCI) is an important and anatomically complex region of the rotator cuff that is critically important to normal glenohumeral function. Recognition of common pathologies in this region on imaging examinations is especially important as injuries may be difficult to detect on clinical examination and even at arthroscopy. Familiarity with the magnetic resonance imaging appearance of the normal and abnormal RCI and the ability to convey findings to orthopedic and sports medicine referrers are essential to facilitate prompt creation of effective treatment plans.

US Appearance of the Rotator Cable with Histologic Correlation: Preliminary Results

PURPOSE

To characterize the ultrasonographic (US) appearance of the rotator cuff cable in asymptomatic shoulders and in cadaveric specimens, with histologic comparison for the latter.

MATERIALS AND METHODS

The cadaveric portion of this study was approved by the institution's Anatomical Donations Department. Institutional review board approval and informed consent were obtained from asymptomatic volunteers and clinical patients for the HIPAA-compliant portion of the study. Four fresh cadaveric shoulder specimens (two male subjects, 40 and 50 years old) were dissected, assessed for the presence of the rotator cable, and imaged with 12-MHz US. Histologic slides (hematoxylin-eosin stain) from three resected rotator cuff tendons were inspected for fibers in the expected location and orientation of the rotator cuff cable. The shoulders in 17 asymptomatic volunteers (seven men, two women; age range, 27-66 years; mean, 41 years) and contralateral asymptomatic shoulders in 10 patients (six men, four women; age range, 24-78 years; mean, 49 years) were scanned and evaluated for the presence and appearance of the rotator cable.

RESULTS

The rotator cable was identified at gross dissection. Histologic examination and US of the cadaveric shoulders demonstrated an articular-sided fibrillar structure perpendicular to the rotator cuff tendon (average thickness and width, 1.2 mm and 4.5 mm, respectively). US of asymptomatic shoulders depicted a similar fibrillar structure in three (11%) shoulders up to 1.1-1.5 cm medial to the greater tuberosity (average thickness and width, 1.2 mm and 4.5 mm respectively).

CONCLUSION

The rotator cable can be depicted with US.

Classification of common acetabular fractures: radiographic and CT appearances

OBJECTIVE

Accurate characterization of acetabular fractures can be difficult because of the complex acetabular anatomy and the many fracture patterns. In this article, the five most common acetabular fractures are reviewed: both-column, T-shaped, transverse, transverse with posterior wall, and isolated posterior wall. Fracture patterns on radiography are correlated with CT, including multiplanar reconstruction and 3D surface rendering.

CONCLUSION

In the evaluation of the five most common acetabular fractures, assessment of the obturator ring, followed by the iliopectineal and ilioischial lines and iliac wing, for fracture allows accurate classification. CT is helpful in understanding the various fracture patterns.

Sonography of Inguinal Region Hernias

OBJECTIVE

The purpose of this article is to describe the anatomy of the inguinal region in a way that is useful for sonographic diagnosis of inguinal region hernias, and to illustrate the sonographic appearance of this anatomy. We show sonographic techniques for evaluating inguinal, femoral, and spigelian hernias and include surgically proven examples.

CONCLUSION

Understanding healthy inguinal anatomy is essential for diagnosing inguinal region hernias. Sonography can diagnose and differentiate between various inguinal region hernias.

MR Imaging of Rotator Cuff Injury: What the Clinician Needs to Know

The rotator cuff muscles generate torque forces to move the humerus while acting in concord to produce balanced compressive forces to stabilize the glenohumeral joint. Thus, rotator cuff tears are often associated with loss of shoulder strength and stability, which are crucial for optimal shoulder function. The dimensions and extent of rotator cuff tears, the condition of the involved tendon, tear morphologic features, involvement of the subscapularis and infraspinatus tendons or of contiguous structures (eg, rotator interval, long head of the biceps brachii tendon, specific cuff tendons), and evidence of muscle atrophy may all have implications for rotator cuff treatment and prognosis. Magnetic resonance imaging can demonstrate the extent and configuration of rotator cuff abnormalities, suggest mechanical imbalance within the cuff, and document abnormalities of the cuff muscles and adjacent structures. A thorough understanding of the anatomy and function of the rotator cuff and of the consequences of rotator cuff disorders is essential for optimal treatment planning and prognostic accuracy. Identifying the disorder, understanding the potential clinical consequences, and reporting all relevant findings at rotator cuff imaging are also essential.

Sonographic diagnosis of an arterioarticular fistula following knee arthrocentesis

An arterioarticular fistula is an unusual complication of knee arthrocentesis. We describe the sonographic findings immediately following a failed clinical attempt at knee arthrocentesis that resulted in an arterioarticular fistula. Spectral Doppler analysis confirmed the jet of blood into the hemarthrosis. Knowledge of anatomy and application of standard technique is necessary to minimize the complications of arthrocentesis.

Golf and Racquet Sports Injuries

There are specific injuries that are common in golf and racquet sports. These abnormalities have a predilection for specific structures as well and can be divided into two categories on the basis of etiology as either chronic repetitive injury or acute trauma. With golf injuries, upper extremity abnormalities prevail and include rotator cuff disease, epicondylitis, wrist tenosynovitis, and hamate hook fracture. Thoracolumbar spine pain can also occur. The order of frequency of these ailments is different for professional and recreational athletes. With racquet injuries, as in tennis, lower extremity injuries are more common and include medial gastrocnemius and Achilles tendon abnormalities, although shoulder, elbow, and wrist abnormalities may also occur. Knowledge of the biomechanics behind each sport is also helpful in understanding the pathophysiology of injury and in part explains the findings seen at imaging.