Publications by authors named "Leon D Rybak"

Objective: Assess the diagnostic accuracy of 3-T indirect magnetic resonance arthrography (iMRA) for hip cartilage and labral pathology detection using arthroscopy as the reference standard and compare it to the published performance of direct magnetic resonance arthrography (dMRA).

Materials And Methods: Between 2009 and 2011, 290 patients suspected of having femoroacetabular impingement underwent iMRA. Our study group consisted of 41 of these patients (17 males, mean age 35 years; 24 females, mean age 33 years) who did not have a prior history of hip surgery and who subsequently underwent arthroscopy.

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Objective: To assess the relationship between knee alignment and subregional T1ρ values of the femorotibial cartilage and menisci in patients with mild (Kellgren-Lawrence grade 1) to moderate (KL3) osteoarthritis (OA) at 3T.

Materials And Methods: 26 subjects with a clinical diagnosis of KL1-3 OA were included and subdivided into three subgroups: varus, valgus, and neutral. All subjects were evaluated on a 3T MR scanner.

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Incidental bone tumors are, by definition, asymptomatic lesions that are discovered through routine radiographs obtained for other reasons. Generally, these lesions are benign and latent, requiring no further intervention except observation. However, occasionally these radiographs will detect benign aggressive processes or even malignant lesions that do require further treatment and referral to a tumor specialist.

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Objective: The purpose of this study was to assess the performance of a near-isotropic 3D turbo spin-echo sequence in comparison with a standard 2D protocol and with arthroscopy in direct 1.5-T MR arthrography of the shoulder.

Subjects And Methods: Dilute gadolinium was injected into three cadaver shoulders, and 3D turbo spin-echo and 2D sequences were evaluated with respect to the signal-to-noise and contrast-to-noise ratios of key tissues.

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Improvement in both hardware and software has opened up new opportunities in magnetic resonance (MR) imaging of the shoulder. MR imaging at 3-T has become a reality, with the prospect of 7-T imaging on the horizon. The art of MR arthrography continues to improve, aided by the use of novel imaging positions.

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Objective: The objective of our study was to evaluate the diagnostic utility of conventional radiography for diagnosing bisphosphonate-related atypical subtrochanteric femoral fractures.

Materials And Methods: Retrospective interpretation of 38 radiographs of complete subtrochanteric and diaphyseal femoral fractures in two patient groups-one group being treated with bisphosphonates (19 fractures in 17 patients) and a second group not being treated with bisphosphonates (19 fractures in 19 patients)-was performed by three radiologists. The readers assessed four imaging criteria: focal lateral cortical thickening, transverse fracture, medial femoral spike, and fracture comminution.

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Synovial chondrosarcoma is a rare tumor, seen most commonly arising from antecedent synovial chondromatosis, the more common benign entity. The distinction between the two can be difficult on the basis of clinical, imaging, and histologic criteria. The authors report a case of pathologically proven synovial chondrosarcoma of the hip in a 45-year-old male initially treated for presumed synovial chondromatosis.

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Objective: The purpose of this study was to evaluate experience with and determine the efficacy and safety of thermal ablation in the management of spinal osteoid osteomas close to neural elements.

Materials And Methods: The records of all patients with osteoid osteomas of the spine managed with thermal ablation at two academic centers from 1993 to 2008 were reviewed.

Results: Seventeen patients (13 male patients, four female patients; mean age, 25.

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Sinus histiocytosis with massive lymphadenopathy or Rosai-Dorfman disease (RDD) is a rare histiocytic proliferative disorder of unknown etiology. Most patients present with lymph node involvement manifesting as adenopathy; however, RDD may arise primarily in a variety of extranodal sites, including bone. We report herein our experience with 15 cases of primary intraosseous RDD.

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We present a case of intraarticular myositis ossificans in the right knee of a child. Myositis ossificans (MO), though relatively rare in childhood and even more uncommon within a joint, should be included in the differential diagnosis of an intra-articular mass when indicated by the typical clinical, radiographic, and histologic findings. An 11-year-old male presented with a history of trauma to his right knee.

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Osteoblastoma is an extremely rare entity that represents less than 1% of all bone tumors, and affects twice as many males as females with peak incidence between 15 and 20 years. Osteoblastomas commonly affect axial bones, long bones, bones of the foot and hand, and less commonly the pelvis, scapula, ribs, and clavicle. Osteoblastoma does not have a classic presentation, but can vary with the location and size of the tumor.

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Thermal ablation of tumors is a rapidly growing field that has found various applications in the musculoskeletal system. Radiofrequency ablation (RFA) has become the reference standard for treatment of most osteoid osteomas. More recently, RFA has been applied to several other forms of primary tumors and in the treatment and palliation of osseous metastases.

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Purpose: To demonstrate that radiofrequency (RF) ablation can be used safely and effectively to treat selected cases of chondroblastoma.

Materials And Methods: Approval was obtained from institutional review boards, research was in compliance with HIPAA protocol. The need to obtain informed consent was waived for retrospective review of patient records.

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Salmonella osteomyelitis occurs infrequently in children without sickle cell disease. Similarly, acute osteomyelitis of the epiphysis has been rarely reported. We present a case of primary epiphyseal osteomyelitis caused by Salmonella in the distal femur of an otherwise healthy 17-month-old child.

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Bizarre parosteal osteochondromatous proliferation (BPOP), or Nora's lesion, is an unusual surface-based lesion of bone found most commonly in the hands and feet. In the original description of the lesion and in all publications that followed, one of the key imaging characteristics used to define this entity was the lack of cortico-medullary continuity with the underlying bone. The authors present 4 unique cases of pathologically proven BPOP in which cortico-medullary continuity with the underlying bone was demonstrated on imaging.

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Magnetic resonance imaging (MRI) is increasingly being used to evaluate muscle injuries because of its unparalleled anatomic resolution and high sensitivity in detecting acute and chronic soft-tissue abnormalities. These features allow detection of characteristic injury patterns that lead to accurate diagnoses and grading of severity. The precise assessment of muscle injuries with MRI plays an important role in determining the treatment plan and prognosis of injured athletes.

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