Semimembranosus tendon avulsion fracture of the posteromedial tibial plateau associated with posterior cruciate ligament tear and capsular rupture.

Semimembranosus tendon avulsion fractures are an uncommon occurrence and are often associated with anterior cruciate ligament (ACL) and medial meniscus tears. We present the imaging features of an unusual case of semimembranosus avulsion fracture of the posteromedial tibial plateau associated with posterior cruciate ligament (PCL) tear, medial meniscus tear, and capsular rupture in a 26-year-old man with a football injury.

Anterosuperior glenoid impingement syndrome.

Anterosuperior glenoid impingement is a well documented cause of shoulder pain. It occurs when there is deep tearing of the subscapularis, with fibers becoming embedded between the anterosuperior glenoid and humeral head. To our knowledge, this has not been described in radiologic literature and we present MRI findings depicting this entity.

Radiological features of Paget disease of bone associated with VCP myopathy.

OBJECTIVE: Mutations in the Valosin-containing protein (VCP) gene cause a unique disorder characterized by classic Paget disease of bone (PDB), inclusion body myopathy, and frontotemporal dementia (IBMPFD). Our objective was to analyze the radiographic features of PDB associated with VCP mutations since there is a dearth of literature on the PDB component of VCP disease. MATERIALS AND METHODS: Radiographic bone surveys were examined in 23 individuals with VCP mutation and compared with their unaffected relatives. Laboratory testing relevant for VCP disease was performed in all individuals. RESULTS: Of the 17 affected individuals with clinical manifestations of VCP disease, 16 of whom had myopathy, radiographic analysis revealed classic PDB in 11 individuals (65%). The mean age of diagnosis for myopathy was 43.8 years and for PDB was 38.1 years of age. Radiological evidence of PDB was seen in one individual (16%) amongst six clinically asymptomatic VCP mutation carriers. Alkaline phosphatase was a useful marker for diagnosing PDB in VCP disease. CONCLUSIONS: Radiographic findings of classic PDB are seen in 52% of individuals carrying VCP mutations at a significantly younger age than conventional PDB. Screening for PDB is warranted in at-risk individuals because of the benefit of early treatment with the new powerful bisphosphonates that hold the potential for prevention of disease.

Enhanced MR imaging of the shoulder, and sternoclavicular and acromioclavicular joint arthritis in primary hemochromatosis.

Shoulder arthritis is a common feature of hemochromatosis. However, a combination of sternoclavicle (SC) and acromioclavicular (AC) joint involvement associated with shoulder is uncommonly seen. We describe the MR imaging findings of the shoulder and SC and AC joint in a patient with primary hemochromatosis. MRI of the left shoulder revealed inflammatory arthritis and 1-cm erosion of the humeral head, enlargement of the anterior glenoid labrum and formation of glenoid labral ovoid mass due to iron deposit. MRI of the AC joint showed inflammation and erosion with joint fluid. Significant contrast enhancement was noted at the SC joint due to inflammation.

Detailed analysis of contrast-enhanced MRI of hands and wrists in patients with psoriatic arthritis.

OBJECTIVE: The objective was to perform detailed analysis of the involved soft tissues, tendons, joints, and bones in the hands and wrists of patients with psoriatic arthritis (PsA). MATERIALS AND METHODS: We reviewed 23 contrast-enhanced MR imaging studies (13 hands and 10 wrists) in 10 patients with the clinical diagnosis of PsA. We obtained clinical information from medical records and evaluated images for the presence of erosions, bone marrow edema, joint synovitis, tenosynovitis, carpal tunnel, and soft tissue involvement. Two board-certified musculoskeletal radiologists reviewed all images independently. Differences were resolved during a subsequent joint session. RESULTS: The average duration of disease was 71.3 months, ranging from 1 month to 25 years. Eight of the 10 wrists (80%) and 6 of the 13 hands demonstrated bone erosions. Bone marrow abnormalities were shown in 5 of the 10 wrists (50%) and 4 of the 14 hands (31%). Triangular fibrocartilage tears were seen in 6 of the 10 wrists (60%). Wrist and hand joint synovitis were present in all studies (67 wrist joints and 101 hand joints). Wrist soft tissue involvement was detected in 9 of the 10 wrists (90%) and hand soft tissue involvement was present in 12 of the 13 wrists (92%). Findings adjacent to the region of soft tissue involvement included synovitis (4 wrists) and tenosynovitis (3 wrists). Bone marrow edema adjacent to the region of soft tissue involvement was seen in one wrist. Bulge of the flexor retinaculum was seen in 4 of the 10 wrists (40%) and median nerve enhancement was seen in 8 of the 10 wrists (80%). Tenosynovitis was seen in all studies (all 10 of the hands and all 13 of the wrists). The "rheumatoid" type of distribution of bony lesions was common in our study. Interobserver agreement for various findings ranged from 83% to 100%. CONCLUSION: Contrast-enhanced MRI unequivocally demonstrated bone marrow edema, erosions, tendon and soft-tissue disease, and median nerve involvement, with good interobserver reliability in patients with PsA of the hands and wrists. Disease was more extensive in the wrists than in the hands.

The role of magnetic resonance imaging in the early diagnosis of rheumatoid arthritis.

Rheumatoid arthritis (RA) is a common disease that affects 1% of the population. With the advent of disease-modifying therapies, it became particularly important to detect RA as early as possible. In this article, we discuss the role of magnetic resonance imaging (MRI) in the imaging of early RA. Imaging of soft tissues manifestations, which precede the development of osseous erosions, is discussed. We also review the role of MRI in establishing correct diagnosis in cases of arthritis, which do not demonstrate classical clinical presentation. The role of MRI in the follow-up of RA is addressed.

Kv1.3 channels are a therapeutic target for T cell-mediated autoimmune diseases.

Autoreactive memory T lymphocytes are implicated in the pathogenesis of autoimmune diseases. Here we demonstrate that disease-associated autoreactive T cells from patients with type-1 diabetes mellitus or rheumatoid arthritis (RA) are mainly CD4+ CCR7- CD45RA- effector memory T cells (T(EM) cells) with elevated Kv1.3 potassium channel expression. In contrast, T cells with other antigen specificities from these patients, or autoreactive T cells from healthy individuals and disease controls, express low levels of Kv1.3 and are predominantly naïve or central-memory (T(CM)) cells. In T(EM) cells, Kv1.3 traffics to the immunological synapse during antigen presentation where it colocalizes with Kvbeta2, SAP97, ZIP, p56(lck), and CD4. Although Kv1.3 inhibitors [ShK(L5)-amide (SL5) and PAP1] do not prevent immunological synapse formation, they suppress Ca2+-signaling, cytokine production, and proliferation of autoantigen-specific T(EM) cells at pharmacologically relevant concentrations while sparing other classes of T cells. Kv1.3 inhibitors ameliorate pristane-induced arthritis in rats and reduce the incidence of experimental autoimmune diabetes in diabetes-prone (DP-BB/W) rats. Repeated dosing with Kv1.3 inhibitors in rats has not revealed systemic toxicity. Further development of Kv1.3 blockers for autoimmune disease therapy is warranted.

Enhanced MR imaging of tenosynovitis of hand and wrist in inflammatory arthritis.

OBJECTIVE: The purpose of this study is to describe the appearance of tenosynovitis in various tendon groups in the wrist and hand and to compare MR enhanced and non-enhanced imaging evaluation of tenosynovitis of hand and wrist in inflammatory arthritis. DESIGN AND PATIENTS: We reviewed 72 MRI studies of hands and wrists, including coronal, axial and sagittal images in 30 consecutive patients with inflammatory arthritis and tenosynovitis. We compared the degree of synovitis on T2-weighted vs contrast-enhanced T1-weighted images, using a predetermined scale. We also measured the extent of tenosynovitis in three dimensions. The tendons were assigned to volar, dorsal, ulnar and radial groups in the wrist and to extensor, flexor and thumb groups in the hand. Degree of tenosynovitis (graded 0-3), cross-sectional area and volume of the inflamed synovium in various tendon groups were then compared by statistical analysis. RESULTS: Review of the medical records revealed the following diagnoses in our patient population: rheumatoid arthritis (n=16), unspecified inflammatory polyarthritis (n=9), psoriatic arthritis (n=2), CREST syndrome (n=1), systemic lupus erythematosus (n=1), paraneoplastic syndrome with arthritis (n=1). The average T2 brightness scores and post-gadolinium enhancement scores were 1.0 and 1.7, respectively (P<0.001) in the wrist studies. The average T2 brightness scores and post-gadolinium enhancement scores were 0.7 and 1.4, respectively (P<0.001) in the hand studies. The average sensitivity of T2-weighted imaging for detection of tenosynovitis was 40% in the hand and 67% in the wrist tendons, when contrast-enhanced images were used as a reference. Carpal tunnel flexor tendons were the most frequently affected tendons of the wrist. The most frequently affected tendons of the hand were second and third flexor tendons. The hand flexors demonstrated higher degrees of enhancement and larger volumes of the inflamed tenosynovium than did the hand extensors and tendons of the thumb. CONCLUSION: Enhanced MR imaging of the hand and wrist is a superior technique for detection of tenosynovitis. We observed carpal tunnel flexor tendons to be the most frequently affected tendons of the wrist. The flexor tendons of the second and third digits were the most frequently affected tendons of the hands. Higher contrast-enhancement scores and inflammation were noted in the hand flexor than in the extensor tendons.

Therapeutic arthrography and bursography.

Arthrography and bursography as therapeutic venues have found their place in the musculoskeletal procedure armamentarium. Therapeutic arthrography not only rules in and rules out the origin of pain but can provide 6 to 9 months of pain relief in diseased joints. Therapeutic arthrography allows injections of anesthetic, corticosteroid, or alternatively hyaluronic acid to be delivered accurately to the source of pain. Corticosteroids have a long history of use in osteoarthritis. Alternative therapy with hyaluronic acid is anew procedure. This article reviews the technique of arthrography in different joints and bursae and discusses the pros and cons of the use of corticosteroids versus viscosupplementation in therapeutic arthrography.

Giant epidermal inclusion cyst of buttock.

Epidermal inclusion cyst is a common benign soft-tissue lesion of skin. It often presents as a small lesion, but rarely grows to a large mass. We are presenting a giant gluteal epidermal inclusion cyst that grew to an enormous size, masquerading as a large soft-tissue neoplasm. Magnetic resonance imaging not only displays the size and margins of these well-encapsulated lesions in three planes, but shows characteristic internal features that may suggest the preoperative diagnosis.

Predicting the strength of femoral shafts with and without metastatic lesions.

To evaluate a potential tool for assessing the risk of a pathologic fracture of the femoral shaft, we examined whether fracture loads computed by our computed tomography scan-based finite element models are predictive of measured fracture loads. We also evaluated whether the precision of the computed fracture loads for shafts with metastases is altered if models are generated using mechanical property-density relationships for bone without metastases. We investigated whether femoral shafts with a hemispheric defect and shafts with metastases have qualitatively similar structural behavior. Using identical four-point bending loading conditions, we computed and measured fracture loads of femoral shafts with and without metastases and with a burred hemispheric defect to simulate a tumor. Finite element model fracture loads were strongly predictive of the measured fracture loads (range, 0.92-0.98) even when the models of bones with metastases used mechanical property relationships for bone without metastases. Specimens with hemispheric defects behaved structurally differently than specimens with metastases, indicating that these defects do not accurately simulate the effects of metastases. Results of our study show that these computed tomography scan-based finite element models can be used to estimate the strength of femoral shafts with and without metastases. These models may be useful for assessing the risk of pathologic fractures of femoral shafts.

Predicting proximal femoral strength using structural engineering models.

Hip fracture related to osteoporosis and metastatic disease is a major cause of morbidity and mortality. An accurate and precise method of predicting proximal femoral strength and fracture location would be useful for research and clinical studies of hip fracture. The goals of this study were to develop a structural modeling technique that accurately predicts proximal femoral strength; to evaluate the accuracy and precision of this predicted strength on an independent data set; and to evaluate the ability of this technique to predict fracture location. Fresh human cadaveric proximal femora with and without metastatic lesions were studied using computed tomography scan-based three-dimensional structural models and mechanical testing to failure under single-limb stance-type loading. The models understated proximal femoral strength by an average of 444 N, and the precision of the predicted strength was +/- 1900 N. Therefore, the ability to predict hip strength in an individual subject is limited primarily by the level of precision, rather than accuracy. This level of precision is likely to be sufficient for many studies of hip strength. Finally, these models predict fractures involving the subcapital and cervical regions, consistent with most fractures produced experimentally under single-limb stance-type loading.

Advances in spinal fusion.

Since its initial description about a century ago, spinal fusion has become a common surgical intervention in the treatment of various debilitating spinal disorders. However, given the complexities and demands of the procedure, patient selection remains a key component in the success of the operation. In this article, we will review the various indications for spinal fusion, the current advances in fusion techniques, as well as the potential complications associated with the procedure.

MRI of large intraosseous lesions in patients with inflammatory arthritis.

OBJECTIVE: The purpose of our study was to evaluate on MRI the occurrence of large cystlike intraosseous lesions in patients with inflammatory arthritis. SUBJECTS AND METHODS: We prospectively reviewed contrast-enhanced MR images of 128 hands and wrists in 44 patients with clinical presentation of inflammatory arthritis. Large lesions (> or = 1 cm) found on MR images were further evaluated for the presence of a cortical break and intraarticular extension. These data were correlated with clinical and laboratory findings and the duration of arthritis. RESULTS: We found 26 patients with rheumatoid arthritis, seven with psoriatic arthritis, two with systemic lupus erythematosus, one with HIV-associated arthritis, one with mixed connective tissue disorder, one with paraneoplastic-associated arthritis, one with inflammatory bowel disease arthritis, and five patients with early unclassified inflammatory arthritis. Twelve patients had 16 large intraosseous lesions, none of which were detected on available radiographs (availability of radiographs for large erosions was 75%). A cortical break with intraarticular extension of the large lesions was seen in 12 cases. Four lesions were not intraarticular. CONCLUSION: Even large intraosseous lesions may be occult on radiography. MRI is a superior technique for detecting these lesions in the small joints of the hand and wrist in inflammatory arthritis. Although large intraosseous erosions often communicate with joints, we observed four large purely intraosseous enhancing lesions without intraarticular connection. Patients with large erosions have a longer duration of inflammatory arthritis.

Musculoskeletal disorders associated with HIV infection and AIDS. Part II: non-infectious musculoskeletal conditions.

This section of a two-part series on musculoskeletal disorders associated with HIV infection and AIDS reviews the non-infectious musculoskeletal conditions. In the first part, the infectious conditions were reviewed. The non-infectious conditions include polymyositis, drug-induced myopathy, myositis ossificans, adhesive capsulitis, avascular necrosis, bone marrow abnormalities, and hypertrophic osteoarthropathy. Inflammatory and reactive arthropathies are more prevalent in HIV-positive individuals, and a separate section is dedicated to these conditions, including Reiter's syndrome, psoriatic arthritis, HIV-associated arthritis, painful articular syndrome, and acute symmetric polyarthritis. Lastly, we include a discussion of HIV-related neoplastic processes that affect the musculoskeletal system, namely Kaposi's sarcoma and non-Hodgkin's lymphoma.

Area beam equalization: optimization and performance of an automated prototype system for chest radiography.

RATIONALE AND OBJECTIVES: To evaluate the feasibility and performance of an x-ray beam equalization system for chest radiography using anthropomorphic phantoms. MATERIALS AND METHODS: Area beam equalization involves the process of the initial unequalized image acquisition, attenuator thickness calculation, mask generation using a 16 x 16 piston array, and final equalized image acquisition. Chest radiographs of three different anthropomorphic phantoms were acquired with no beam equalization and equalization levels of 4.8, 11.3, and 21. Six radiologists evaluated the images by scoring them from 1-5 using 13 different criteria. The dose was calculated using the known attenuator material thickness and the mAs of the x-ray tube. RESULTS: The visibility of anatomic structures in the under-penetrated regions of the chest radiographs was shown to be significantly (P < .01) improved after beam equalization. An equalization level of 4.8 provided most of the improvements with moderate increases in patient dose and tube loading. Higher levels of beam equalization did not show much improvement in the visibility of anatomic structures in the under-penetrated regions. CONCLUSION: A moderate level of x-ray beam equalization in chest radiography is superior to both conventional radiographs and radiographs with high levels of beam equalization. X-ray beam equalization can significantly improve the visibility of anatomic structures in the under-penetrated regions while maintaining good image quality in the lung region.

Advanced imaging of early rheumatoid arthritis.

Advances in MR imaging of arthritis include contrast-enhanced, dynamic, and quantitative imaging techniques. These advances may result in MR imaging becoming the gold standard in diagnosing early RA. MR imaging is a useful technique in diagnosis, follow-up, and evaluation of remission in rheumatic diseases of the joints. Early diagnosis of RA, in the first 6 months after the onset of symptoms, may lead to earlier control and prevent future erosions and deformities.

Musculoskeletal disorders associated with HIV infection and AIDS. Part I: infectious musculoskeletal conditions.

The musculoskeletal system can be affected by a variety of abnormalities in association with human immunodeficiency virus (HIV) infection. Although not as common as complications involving other organ systems, such as the pulmonary and the central nervous systems, HIV-associated musculoskeletal disorders are sometimes the initial presentation of the viral illness. Knowledge of the existence and the characteristic appearance of the conditions affecting bone, joint, and muscle in HIV-infected patients is valuable to radiologists for diagnosis and to clinicians for detection and appropriate treatment. We reviewed recent literature to provide a comprehensive assessment of the HIV-associated musculoskeletal disorders, and present radiologic examples from our own collection. This article is divided into two parts. In the first part we review the infectious musculoskeletal disorders associated with HIV illness and AIDS, including cellulitis, abscesses, pyomyositis, septic bursitis, septic arthritis, osteomyelitis, and bacillary angiomatosis. We also present a comprehensive spectrum of mycobacterial infections, consisting of tuberculous spondylitis and spondylodiskitis, arthritis, osteomyelitis, and tenosynovitis, as well as infections caused by atypical mycobacteria. Part II of this review will concentrate on non-infectious musculoskeletal conditions, including rheumatic disorders and neoplasms.

Mechanical properties, density and quantitative CT scan data of trabecular bone with and without metastases.

Pathologic fracture of the hip due to metastatic lesions in bone is a serious problem. This study examined the effect of metastatic lesions on the material properties and quantitative computed tomography (QCT) data of trabecular bone. Twelve distal femora were obtained, four with lytic and/or blastic metastatic lesions (group L), four without lesions but from donors who died from breast, prostate, or lung cancer (group NL), and four from donors with no cancer (group NC). Each specimen was CT scanned, and 56, 15x15x15-mm cubes of trabecular bone were cut. QCT density (rho(QCT)), compressive elastic modulus (E), compressive yield and ultimate strengths (S(y) and S(u)), and ash density (rho(ash)) of each cube were determined. Regression analysis was performed between rho(ash) and E, S(y), S(u) and rho(QCT), and analysis of covariance was used to identify differences between groups. Power relationships that did not depend on group (p >/= 0.1) were found between E and rho(ash) (0.74 /= 0.94; p<0.001). rho(ash) was strongly related to rho(QCT) (r >/= 0.99; p<0.001). These results indicate that metastatic disease does not significantly impair the ability of QCT to provide an accurate and precise estimate of rho(ash) that can be used to estimate mechanical properties of trabecular bone with and without metastases.

Advances in MR imaging of vertebral collapse.

Vertebral collapse is a frequently encountered entity in clinical practice. While diagnosing acute, benign traumatic types is usually not complicated, difficulties arise in determining the etiology of vertebral collapse when there is no history of significant trauma, especially in older populations. Considering up to one-third of vertebral collapse in patients with a known primary malignancy are benign, the diagnosis becomes even more difficult when there is a history of malignancy. Additionally, because primary cancer patients may be immunocompromised, the possibility of infectious vertebral collapse should also be entertained. The purpose of this article is to review all recent magnetic resonance imaging aspects of differentiating osteoporotic, malignant, and infectious vertebral collapse.