Faculty Bibliography

OBJECTIVE: To evaluate the degree and location patterns of subscapularis tendon injury in patients with prior anterior shoulder dislocation (ASD). MATERIAL AND METHODS: Forty-five consecutive MR shoulder examinations in patients with a history of ASD and 20 consecutive MR examinations in patients without prior dislocation were reviewed. Two readers assessed for the presence and location of tendinosis and tearing in the subscapularis tendon, which was divided into three segments: superior, middle, and inferior. The readers also documented the presence of anterior labral tears, osseous Bankart defects and Hill-Sachs lesions. Fisher's exact tests were performed to analyze the different types of pathology and their locations. RESULTS: Subscapularis tendinosis, and partial thickness and full thickness tears were more common in patients with a history of ASD. Tendinosis was found in 60-64.4% of the dislocation patients compared with 40% of the non-dislocation group. When stratified by location, the middle and inferior thirds were the most commonly affected with statistical significance (p < 0.05) found in tearing of the inferior third. Anterior labral tears, osseous Bankart defects, and Hill-Sachs lesions were more common in the dislocation group with statistically significant associations with tendinosis in the middle and inferior thirds and tearing of the middle third (p < 0.05). CONCLUSION: Our study suggests an association between middle and inferior subscapularis tendon pathology and prior anterior shoulder dislocation. Based on our results, careful MR assessment of the subscapularis tendon by the radiologist is indicated in the setting of ASD as injury of this structure can be symptomatic and may be amenable to treatment.

MRI has been shown to be both sensitive and specific in the diagnosis of partial thickness and full-thickness tears of the rotator cuff. Recognizing the pattern of a rotator cuff tear before surgery also provides useful information to the referring clinician as it can help in the selection of the type of surgery and lead to a better anatomic and biomechanical restoration of the cuff tendons. There is relative paucity of published reports exploring the performance of MRI in the recognition and classification of rotator cuff tears based on their morphological pattern. The purpose of this exhibit is: 1) to describe the geometric patterns of rotator cuff tears, 2) to illustrate the MR imaging appearance of the different patterns of rotator cuff tearing, 3) to describe the clinical significance of the different patterns in terms of treatment selection and outcome prediction. Characterization of the most common rotator cuff tear patterns will be presented including: crescent-shaped, U-shaped, L-shaped, and massive cuff tears. This will be followed by a guide that can be used to recognize these patterns on MRI utilizing the location as well as the size of the transverse and longitudinal components of the tear on surgically proven cases. Finally, a review of the different types of repairs currently available for each tear pattern will be presented including end-to-bone repair and margin convergence techniques as well as the expected postsurgical outcomes

Purpose: To create a guide for the radiologist to help him/her learn how to recognize and interpret normal anatomy and basic pathology on arthroscopic images using MRI. Materials/Methods: We will give an introduction to shoulder arthroscopy and compare its strengths/weaknesses to MRI. The arthroscopy introduction will include a description of the patient positions used during surgery, portals used, and a roadmap that will help the radiologist navigate through the shoulder anatomy on the surgical images. Normal anatomy and pathology will be presented on arthroscopic and MR images from the same patient, providing direct comparison and contrast of the two modalities. Results: The viewer will review the following normal anatomy on arthroscopy and MRI: biceps anchor/tendon, labrum, glenoid and humeral cartilage, articular and bursal rotator cuff, rotator interval/ biceps pulley, and acromioclavicular joint. This will be followed by a review of common shoulder pathologies, including: SLAP tears, anterior labral tear, GLAD lesion, bicep's pulley lesion, full-thickness rotator cuff tear, osseous Bankart lesion, and Hill-Sachs lesion. Conclusion: The goal for this presentation is to familiarize the radiologist with the basics of shoulder arthroscopy with special attention to the appearance of normal anatomy and common pathology. This will hopefully lead to an improved understanding of the relationship between these two imaging modalities and the common pathologies that inflict the shoulder

The rotator cable, an extension of the coracohumeral ligament, is a fibrous band-like structure that courses along the undersurface of the supraspinatus and infraspinatus tendons perpendicular to their tendon fibers. Originally described in the orthopaedic literature, the rotator cable likely plays an important role in the biomechanics of the intact and torn rotator cuff. Published data addressing the performance of MR imaging in the evaluation of the rotator cable is rather limited. The purpose of this exhibit is threefold: 1) to describe the normal gross anatomy, histology, as well as the MR imaging anatomy of the rotator cable, 2) to describe the role of imaging as it pertains to the cable's function in the biomechanics of the intact and torn rotator cuff, 3) to underscore the clinical significance of the cable in terms of classification and treatment of rotator cuff tears. Introduction to the most current knowledge on the origin, distribution, and insertions of the rotator cable using gross anatomy, histology, and MR imaging correlation will be presented. Emphasis will be placed on the MR appearance of the rotator cable in orthogonal imaging planes in both intact and torn rotator cuffs. The role of the rotator cable in the setting of rotator cuff pathology will be underscored using MRI, including its potential contributions to the geometric configuration of cuff tears, altered glenohumeral biomechanics, and fatty degeneration of the rotator cuff musculature. Lastly, a review of the clinical importance of the rotator cable will be provided focused on the effect of the cable's integrity in the management of rotator cuff tears

The rotator cable is an extension of the coracohumeral ligament coursing along the undersurface of the supraspinatus and infraspinatus tendons. The rotator cable is thought to play a role in the biomechanical function of the intact and torn rotator cuff. It can be seen on all the imaging planes used for the conventional magnetic resonance imaging of the shoulder. Clinically, the integrity of the rotator cable can play a role in the treatment selection for patients with a rotator cuff tear.

The use of bioabsorbable cross-pin transcondylar fixation has remained a viable option for femoral fixation in anterior cruciate ligament reconstruction. Although numerous biomechanical studies have demonstrated high fixation strength and minimal slippage with use of this method of fixation, there have been increasing reports of a variety of clinical complications associated with these implants. We reviewed the literature for all complications associated with the Bio-TransFix implant and present a case report of a patient status after ACL reconstruction using Bio-TransFix cross-pin femoral fixation with iliotibial band friction syndrome from a broken cross-pin four month post-operatively.

Early detection of cartilage degeneration in the hip may help prevent onset and progression of osteoarthritis in young patients with femoroacetabular impingement. Delayed gadolinium-enhanced MRI of cartilage is sensitive to cartilage glycosaminoglycan loss and could serve as a diagnostic tool for early cartilage degeneration. We propose a new high resolution 2D T(1) mapping saturation-recovery pulse sequence with fast spin echo readout for delayed gadolinium-enhanced magnetic resonance imaging of cartilage of the hip at 3 T. The proposed sequence was validated in a phantom and in 10 hips, using radial imaging planes, against a rigorous multipoint saturation-recovery pulse sequence with fast spin echo readout. T(1) measurements by the two pulse sequences were strongly correlated (R(2) > 0.95) and in excellent agreement (mean difference = -8.7 ms; upper and lower 95% limits of agreement = 64.5 and -81.9 ms, respectively). T(1) measurements were insensitive to B(1+) variation as large as 20%, making the proposed T(1) mapping technique suitable for 3 T. Magn Reson Med, 2011. (c) 2011 Wiley-Liss, Inc

OBJECTIVE: Criteria for sonographic diagnosis of monosodium urate (MSU) crystal deposition have been developed, but the interreader reproducibility of this modality is not well established. We therefore assessed agreement using a systematic approach. METHODS: Fifty male subjects ages 55-85 years were recruited during primary care visits to an urban Veterans Affairs hospital, and were assessed by musculoskeletal ultrasound (US) of the knees and first metatarsophalangeal (MTP) joints to evaluate for the double contour sign and tophi as evidence of MSU crystal deposition. Images were read by 2 blinded rheumatologists trained in musculoskeletal US, and the degree of concordance was determined for individual subjects, total joints, femoral articular cartilage (FAC), and first MTP joints. Subjects were further categorized into 3 diagnostic groups: gout, asymptomatic hyperuricemia (no gout, serum uric acid [UA] >/=6.9 mg/dl), and controls (no gout, serum UA </=6.8 mg/dl), and reader concordance within these 3 groups was assessed. RESULTS: We observed almost perfect agreement between readers for 1) individual subjects (yes/no; n = 50, 100% agreement, kappa = 1.000), 2) total joints (n = 200, 99% agreement, kappa = 0.942), 3) FAC (n = 100, 99% agreement, kappa = 0.942), and 4) first MTP joints (n = 100, 99% agreement, kappa = 0.942). Furthermore, findings by side (right/left) and diagnostic group (gout, asymptomatic hyperuricemia, control) showed substantial to almost perfect concordance for all measures. MSU deposition was seen most commonly in gout patients, and deposition was also seen in some subjects with asymptomatic hyperuricemia, but in only 1 control. CONCLUSION: Musculoskeletal US is reliable for detecting MSU deposition in FAC and first MTP joints in gout and asymptomatic hyperuricemia

OBJECTIVE: The objective of this study was to assess the prevalence of increased signal intensity in the pronator quadratus in the general patient population. Using region-of-interest measurements, we measured the signal intensity of the pronator quadratus and of an adjacent flexor muscle. In addition, we performed independent subjective assessments of the pronator quadratus. CONCLUSION: Increased signal intensity in the pronator quadratus is a frequent normal finding of unclear etiology and is not related to disease. Familiarity with this normal phenomenon is important to avoid overdiagnosis of denervation due to anterior interosseous nerve entrapment.

This article focuses on the variants and imaging pitfalls in the ankle and foot