Imaging appearances of Buerger's disease complications in the upper and lower limbs.

Thromboangiitis obliterans (Buerger's disease) is a rare, non-atherosclerotic, segmental, inflammatory vasculitis that most commonly involves small and medium-sized arteries, veins and nerves of the extremities and affects tobacco smokers between the ages of 25 and 45 years. The manifestations of Buerger's disease can be extremely variable and, therefore, awareness of the condition is important for both general and musculoskeletal radiologists. This paper presents the radiological appearance of the sequelae of Buerger's disease involving the upper and lower limbs.

Adductor insertion avulsion syndrome, "thigh splints": relevance of radiological follow-up.

We present a case of chronic osteomyelitis in a 13-year-old girl which was originally diagnosed as adductor insertion avulsion syndrome ("thigh splints") on the basis of the clinical presentation, patient history, initial radiographs and MRI examination. However, at follow-up with persistent pain and altered radiographic and MRI appearances, surgical biopsy was indicated. Histopathological findings confirmed a bone abscess. This case underlines the necessity of clinical follow-up and imaging in certain patients with apparent thigh splints.

Shoe rim and shoe buckle pseudotumor of the ankle in elite and professional figure skaters and snowboarders: MR imaging findings.

OBJECTIVE: To review MR imaging of figure skaters and snowboarders presenting with painful soft-tissue swelling of the lateral supramalleolar region with a clinical provisional diagnosis of soft-tissue tumor. DESIGN AND PATIENTS: MR imaging was prospectively reviewed by two sub-specialized musculoskeletal radiologists. The findings were correlated with a second clinical review and examination of the shoe wear. The patients were four female athletes undergoing heavy training regimes, ranging in age between 16 and 25 years. Two patients were elite figure skaters, and two were professional snowboarders. Three patients had unilateral masses with pain, and one patient presented with bilateral clinical findings. RESULTS: MR imaging showed subcutaneous, focal soft-tissue masses of the supramalleolar region in five ankles at the same level above the ankle joint. MR imaging prompted a second clinical review and correlation with the shoe wear. The MR imaging findings correlated to the level of the shoe rim or shoe buckle in all patients, confirming the suspected MR imaging diagnosis of an impingement syndrome. All four sportswomen were training excessively, ignoring safety advice regarding training duration, timing of breaks, and shoe wear rotation. CONCLUSION: Ice skaters and snowboarders may present with persistent and disabling pain. On MR imaging, this corresponds to a focal soft-tissue abnormality, which may be due to subcutaneous fat impingement between the fibula and the shoe rim or shoe buckle.

Magnetic resonance evaluation of the interrelationship between articular cartilage and trabecular bone of the osteoarthritic knee.

OBJECTIVE: To use high-resolution magnetic resonance imaging (MRI) to determine the relationship between articular cartilage degeneration and trabecular bone changes of the femur, condyles and tibia in human knees with osteoarthritis (OA). METHODS: Subjects were divided into three groups: without OA (OA0), mild OA (OA1) and severe OA (OA2). Sagittal images of the knee (0.234 x 0.234mm2, 2-mm slice thickness) were obtained at 1.5T and used for calculating the volume and thickness of the femoral and tibial cartilage. Axial images (0.195 x 0.195mm2, 1-mm slice thickness) were used for calculating the trabecular bone structure parameters: apparent bone volume fraction, trabecular number, trabecular separation and trabecular thickness. RESULTS: Cartilage volume and thickness were less in patients with OA compared to normal controls (P<0.1). Articular cartilage thinning is associated with bone structure loss in the opposite femoral condyle (P<0.05). In varus OA, there were extensive correlations between medial tibia and medial femoral cartilage degeneration, and loss of bone structure in the lateral tibia and lateral condyle. Additional correlations existed between the compartmental differences (lateral minus medial) of cartilage thickness and bone structure. CONCLUSION: Degradation of articular cartilage within a compartment correlates with a loss of bone structure in the opposite compartment. The correlation between the (L-M) differences corroborates this relationship. Malalignment of the knee due to cartilage degeneration is associated with bone formation in the diseased condyle and bone resorption in the opposite compartment.

MR imaging of calcification of the lateral collateral ligament of the knee: a rare abnormality and a cause of lateral knee pain.

OBJECTIVE: Our objective was to describe the radiologic appearances of calcification of the lateral collateral ligament (LCL) of the knee in four patients who presented with acute atraumatic lateral knee pain. This rare abnormality has not, to our knowledge, been previously shown on MR imaging. CONCLUSION: Calcification of the LCL of the knee is a rare cause of lateral knee pain and is thought to reflect underlying hydroxyapatite deposition. On MR imaging, calcification of the LCL may be associated with an aggressive appearance that can be mistaken for other knee abnormalities.

Imaging of chronic recurrent multifocal osteomyelitis of childhood first presenting with isolated primary spinal involvement.

OBJECTIVE: Initial presentation with primary spinal involvement in chronic recurrent multifocal osteomyelitis of childhood (CRMO) is rare. Our objective was to review the imaging appearances of three patients who had CRMO who initially presented with isolated primary spinal involvement. DESIGN AND PATIENTS: The imaging, clinical, laboratory and histology findings of the three patients were retrospectively reviewed. Imaging included seven spinal MR imaging scans, one computed tomography scan, nine bone scans, two tomograms and 16 radiographs. These were reviewed by two musculoskeletal radiologists and a consensus view is reported. All three patients presented with atraumatic spinal pain and had extensive bone spinal pathology. The patients were aged 11, 13 and 12 years. There were two females and one male. RESULTS AND CONCLUSIONS: The initial patient had thoracic T6 and T8 vertebra plana. Bone scan showed additional vertebral body involvement. Follow-up was available over a 3 year period. The second patient had partial collapse of T9 and, 2 years later, of C6. Subsequently extensive multifocal disease ensued and follow-up was available over 8 years. The third patient initially had L3 inferior partial collapse and 1 year later T8 involvement with multifocal disease. Follow-up was available over 3 years. The imaging findings of the three patients include partial and complete vertebra plana with a subchondral line adjacent to endplates associated with bone marrow MR signal alterations. Awareness of the imaging appearances may help the radiologist to include this entity in the differential diagnosis in children who present with spinal pathology and no history of trauma. Histopathological examination excludes tumor and infection but with typical imaging findings may not always be necessary.

Imaging features of pseudoaneurysms of the hand in children and adults.

OBJECTIVE: Our objective was to review the imaging features of pseudoaneurysms of the hand in 25 patients. The patients presented with a mass, peripheral paresthesia, or ischemia. Pseudoaneurysm of the hand is a rare and often clinically unsuspected diagnosis. Correct diagnosis is important because there are risks for distal embolic disease with ischemia or gangrene of the fingers, ulnar or digital nerve dysfunction, rupture, or bone erosion and joint destruction. Scant reports appear in the world literature, and this report is the first review, to our knowledge, of the imaging features. The cause may be a history of a single direct trauma or chronic trauma, as seen in patients with hypothenar or thenar hammer syndrome. CONCLUSION: Awareness of the specific imaging appearances of pseudoaneurysms of the hand and their complications may improve the accuracy of radiologic diagnosis, advance the preoperative workup, and prevent possible clinical complications such as digital gangrene, nerve dysfunction, and aneurysm rupture.

Imaging findings in Mazabraud's syndrome: seven new cases.

OBJECTIVE: To present seven new cases of Mazabraud's syndrome with particular observations on the magnetic resonance imaging findings and a review of the literature. DESIGN AND PATIENTS: A multi-institutional retrospective review was performed on seven patients with confirmed Mazabraud's syndrome. The patient group was composed of six women and one man, ranging in age from 39 to 65 years, with a mean age of 53 years. RESULTS: Fibrous dysplasia was more often polyostotic ( n=6) and right-sided ( n=4). Fibrous dysplasia involved the femur in five cases. The soft tissue myxomas were multiple in four cases and were intramuscular in origin. The most commonly affected location was the thigh ( n=4). On computed tomography, myxomas were well-circumscribed, low-attenuation masses. On magnetic resonance images, the lesions were significantly low in signal intensity on T1-weighted images and high in signal intensity on T2-weighted images relative to adjacent skeletal muscle. Enhancement of the myxomas was heterogeneous with irregular, peripheral rim enhancement, and a variable degree of central enhancement depending on the abundance of solid myxoid tissue and bridging fibrous septa. CONCLUSIONS: Knowledge of Mazabraud's syndrome and the imaging appearance of intramuscular myxoma is important in order to avoid unnecessary biopsies of the osseous and soft tissue lesions. The unique features of this disorder allow discrimination from soft tissue malignancies such as sarcoma.

Hibernoma: imaging characteristics of a rare benign soft tissue tumor.

Hibernoma is a rare benign soft tissue tumor of brown fat. Awareness of the MR imaging appearances of this lesion may allow for improved preoperative diagnosis or at least inclusion of hibernoma as a possible benign differential diagnosis prior to surgery.

Primary leiomyosarcoma of bone.

We report a case of primary leiomyosarcoma in the right femoral diaphysis. Conventional radiographs revealed an indistinct osteolytic lesion with a very subtle periosteal reaction. MR imaging revealed an intramedullary lesion with a well-defined margin, cortical breakthrough and soft tissue extension. The lesion was isointense relative to muscle on T1-weighted imaging, iso-hypointense relative to fat on fast spin echo T2-weighted imaging, and hyperintense to muscle on fast spin echo T2-weighted imaging with fat saturation. A peripheral rim and intratumoral spoke-wheel-like enhancement in the soft tissue component of the tumor was noted on gadolinium-enhanced T1-weighted imaging with fat saturation. Such an enhancing pattern, which has not been described in the literature previously but has been seen in leiomyosarcomas elsewhere by both MR imaging and computed tomography, deserves further pathological correlation.

Primary osteoarthritis of the hip: etiology and epidemiology.

Primary osteoarthritis (OA) of the hip has a distinct etiology and epidemiology compared with other types of arthropathy in the hip joint. Arthritis of the hip can be secondary to conditions such as osteonecrosis, trauma, sepsis, or rheumatoid arthritis. Certain conditions, such as congenital hip disease and slipped capital femoral epiphysis, involve predisposing anatomic abnormalities; in such cases, the term "secondary OA" is used. When either an anatomic abnormality cannot be determined or other specific causative entities are not identified, primary OA is the diagnosis of exclusion. The prevalence of hip OA is about 3% to 6% in the Caucasian population and has not changed in the past four decades. In contrast, studies in Asian, black, and East Indian populations indicate a very low prevalence of hip OA. Statistics on patients who underwent total hip replacement for primary OA in San Francisco and Hawaii demonstrate a virtual absence of the condition in Asians and low rates in the black and Hispanic populations. Family studies from Sweden, Britain, and the United States show increased rates of hip OA in first-degree relatives of the index patient when compared with the normal population. Occupations requiring heavy lifting, farming, and elite sports activity are associated with increased rates of hip OA. The low prevalence of hip OA in Asian and black populations in their native countries; the low incidence of total joint replacement for primary OA in Asian, black, and Hispanic populations in North America; and the familial association of hip OA in Caucasians all suggest that genetic factors may be involved in the occurrence of this disease.

Pseudo-osteomyelitic crisis upon presentation of Gaucher disease.

We report on a 4-year-old boy adopted from Paraguay who presented with an acute onset of thigh pain. Initial clinical, imaging, and histopathologic findings suggested florid osteomyelitis. However, the development of pancytopenia on intravenous antibiotics prompted further investigation and the ultimate diagnosis of Gaucher disease. In retrospect, characteristic changes on conventional radiographic and MR images, as well as growth of a contaminant organism, pointed to the diagnosis of pseudo-osteomyelitis rather than osteomyelitis.

MR Imaging of sports-related pseudotumor in children: mid femoral diaphyseal periostitis at insertion site of adductor musculature.

OBJECTIVE: The objective of this study was to review the imaging appearance of the femurs of five patients who had been referred from outside institutions after presenting with thigh pain and being given a preliminary diagnosis of primary malignant bone tumor. Typically, when making a diagnosis, physicians place emphasis on the characteristic appearances of diseases on MR imaging, but such appearances may be misleading. An awareness of the specific MR imaging pattern of stress-related partial muscle avulsion can lead to the correct diagnosis. CONCLUSION: Femoral diaphyseal periostitis after a sports injury to the adductor musculature in children has a characteristic imaging appearance. This condition can initially appear to be misleadingly aggressive. Knowledge of the findings-particularly of the findings on MR imaging-in the proper clinical setting can help physicians make the correct diagnosis and eliminate unnecessary biopsy or inappropriate treatment.

Peripheral nerve ectopic meningioma at the elbow joint.

A rare peripheral ectopic meningioma of the nerve in the elbow region is discussed. The clinical, radiological, surgical and pathological findings are reviewed.

Calcium pyrophosphate dihydrate crystal deposition disease: imaging perspectives.

Calcium pyrophosphate dihydrate (CPPD) crystal deposition disease is widespread in elderly persons and has various clinical presentations that can be confounding to clinicians. It is characterized by acute, subacute, or chronic joint inflammation and deposition of CPPD crystals in hyaline cartilage, fibrocartilage, and other soft tissue structures. We have learned a great deal about imaging findings of CPPD crystal deposition disease. New facts about the disorder and clues to radiologic diagnosis continue to be revealed. This article will provide a review of imaging characteristics of this disease with emphasis on some recent findings. The nomenclature, epidemiology, classification, and pathophysiology will be explained. A discussion of the clinical manifestations and treatment will be followed by a review of the characteristic imaging features.

MR imaging of degenerative diseases in the cervical spine.

This article reviews three topics of fundamental importance in MR imaging of degenerative diseases in the cervical spine: (1) common clinical presentations that determine whether an MR examination is ordered and the ultimate significance ascribed to MR imaging results; (2) imaging techniques; and (3) MR imaging of the major types of cervical spine degeneration.

Calcium pyrophosphate dihydrate crystal deposition in and around the atlantoaxial joint: association with type 2 odontoid fractures in nine patients.

PURPOSE: To investigate the histopathologic anatomy of calcium pyrophosphate dihydrate (CPPD) crystal deposition in and around the atlantoaxial joint and the association between CPPD crystal deposition and subchondral cysts, erosions, and fracture involving the odontoid process of the axis. MATERIALS AND METHODS: One adult cadaver demonstrating calcification in the retro-odontoid area at computed tomography (CT) was selected for further radiography, CT, and magnetic resonance (MR) imaging at the C1-2 level. Anatomic sectioning and histologic evaluations were performed in the specimen. For clinical study, radiographs (n = 5), CT scans (n = 8), and MR images (n = 6) in nine patients (mean age, 74.4 years) with odontoid process fractures and CPPD crystal deposits in and around the atlantoaxial joint were reviewed. RESULTS: In the cadaveric specimen, radiography and CT demonstrated calcifications in the transverse ligament; histologic evaluation confirmed that these calcifications were CPPD crystal deposits. In all nine patients, radiography (n = 5) and CT (n = 8) also showed calcification in areas adjacent to the odontoid process, which included the transverse ligament. T1- and T2-weighted MR imaging showed a retro-odontoid mass of low signal intensity that compressed the cervical cord in six patients. CT, MR imaging, or both demonstrated subchondral cysts, osseous erosions, or a type 2 odontoid fracture in all patients. CONCLUSION: CPPD crystal deposition disease involving the C1-C2 articulation can be a clinically important entity that may place affected patients at increased risk of pathologic fracture of the odontoid process.

MR imaging of the ischiopubic synchondrosis.

The ischiopubic synchondrosis (IPS) is a temporary joint, occurring in childhood prior to fusion of the ischial and pubic bones. On conventional radiographs this tumor-like appearance is a well known normal anatomic variant, however, there are no reports in the literature of the appearance of IPS on MRI. Therefore the purpose of this study was to evaluate typical magnetic resonance features of the IPS. All pelvic MRIs from 1/1992 to 4/1998 of children ranging in age from 4 to 16 years, who were scanned for reasons other than bone disorders, were retrospectively investigated. Twenty-eight children were included and the morphologic appearance of IPS on MRI was evaluated. Seventeen (61%) of these 28 children had the following findings of IPS on MRI. Listed in order of frequency we found signal alteration of the ischiopubic fusion zone [hyperintense on T(2) with fat-saturation (89%) or STIR (74%), hypointense on T(1) (71%)], fibrous "bridging" (68%) [hypointense band on all sequences in perpendicular orientation to the axis of the inferior pubic ramus], fusiform swelling (68%), signal alteration of the adjacent soft tissue (57%) and irregular margins (56%). In 10 children contrast enhanced scans were available for evaluation, showing contrast enhancement of the bone marrow in 83.3% and of the adjacent soft tissue in 66.7%. Fusiform swelling of the ischiopubic fusion zone, signal alteration and contrast enhancement of both the bone marrow and the adjacent soft-tissue are characteristic features of the IPS on MRI, which may be due to mechanical stress at this temporary joint. These features are nonspecific and may resemble tumor, infection or trauma. Fibrous "bridging" was the only finding on MRI, which has not been described for any other entity and thus, it seems to be a characteristic MRI-feature.

MR imaging of clear cell sarcoma (malignant melanoma of the soft parts): a multicenter correlative MRI-pathology study of 21 cases and literature review.

OBJECTIVE: To evaluate MR imaging and pathology findings in order to define the characteristic features of clear cell sarcoma of the soft tissues (malignant melanoma of the soft parts). DESIGN AND PATIENTS: MR examinations of 21 patients with histologically proven clear cell sarcoma of the musculoskeletal system were retrospectively reviewed and assessed for shape, homogeneity, delineation, signal intensities on T1- and T2-weighted images, contrast enhancement, relationship with adjacent fascia or tendon, secondary bone involvement, and intratumoral necrosis. In 19 cases the pathology findings were available for review and for a comparative MR-pathology study. RESULTS: On T1-weighted images, lesions were isointense (n=3), hypointense (n=7) or slightly hyperintense to muscle (n=11). Immunohistochemical examination was performed in 17 patients. All 17 specimens showed positivity for HMB-45 antibody. In nine of 11 lesions with slightly increased signal intensity on T1-weighted images, a correlative MR imaging-pathology study was possible. All nine were positive to HMB-45 antibody. CONCLUSIONS: Clear cell sarcoma of the musculoskeletal system often has a benign-looking appearance on MR images. In up to 52% of patients, this lesion with melanocytic differentiation has slightly increased signal intensity on T1-weighted images compared with muscle. As the presence of this relative higher signal intensity on T1-weighted images is rather specific for tumors displaying melanocytic differentiation, radiologists should familiarize themselves with this rare entity and include it in their differential diagnosis when confronted with a well-defined, homogeneous, strongly enhancing mass with slightly higher signal intensity compared with muscle on native T1-weighted images.