BPOP in early childhood following resection of osteochondroma: report of a case.

The diagnosis of an osteochondroma in the short bones of the extremities is atypical and the presentation in infancy is unusual. A 3-month-old female presented for evaluation of radial deviation of the right index finger present since birth. Radiographs showed a broad-based osseous outgrowth with the usual features of an osteochondroma arising from the base of middle phalanx. Initial corrective surgery at 22 months was followed by recurrence of the lesion. Another resection at 4 years confirmed a final diagnosis of BPOP (bizarre parosteal osteochondromatous proliferation). The subsequent pathologic diagnosis of BPOP appears to support the hypotheses concerning the etiology of BPOP as possibly arising from repeated trauma to the metaphysis.

Unexplained "massive osteolysis of femoral head" (MOFH) after acetabular fracture: occurrence and suggested patho-etiology.

Background We observed cases of extensive osteolysis of the femoral head following acetabular fractures even though the original fracture did not involve the femoral head or neck. This observation has been called massive osteolysis of the femoral head (MOFH). Purpose To evaluate the clinical and imaging features of MOFH to gain a better understanding of its patho-etiology. Material and Methods We retrospectively collected cases of acetabular fractures seen over a period of 10 years and evaluated the clinical features and imaging characteristics. The findings were compared with the features of other complications such as osteonecrosis, rapidly progressive osteoarthritis, or post-traumatic osteolysis. Results Fifteen patients (M:F ratio 9:6; mean age, 61.6 years) out of 244 had MOFH (prevalence: 6.1%). Motor vehicle collision and falls were the most common mechanisms of injury. The time interval for developing MOFH was in the range of 1-18 months after the initial injury. Patterns of femoral head osteolysis varied from eccentric (12 cases) to transcervical (3 cases). Four cases of eccentric osteolysis developed high-degree of osteolysis. MOFH was observed near the surgical hardware in 6/15 cases. One biopsy specimen did not reveal typical features of osteoarthritis or avascular necrosis. Conclusion MOFH appears to be a distinct entity from avascular necrosis or rapidly progressive osteoarthritis. It is suggested that MOFH is a variant of post-traumatic osteolysis that is evident in a subset of patients.

Musculoskeletal imaging insight 2015: Kenya.

Over the past 6 years the International Skeletal Society (ISS) outreach programs have become popular amongst the various radiology organizations in sub-Saharan Africa. So much so that that the ISS outreach is now routinely expected to participate in many of the international radiology conferences in that part of the world. The organizational planning for an outreach visit to Kenya took place over a 3-year period. Eventually a double-headed event; the seventh and eighth sub-Saharan outreach efforts were organized in Nairobi and in Mombasa, Kenya. The Nairobi outreach was an educational course on musculoskeletal imaging at the University of Nairobi and the Aga Khan University in Nairobi from 26 to 28 May 2015. The Mombasa outreach was organized in collaboration with the African Society of Radiology (ASR) at their annual meeting in Mombasa from 30 May to 2 June 2015.

International Skeletal Society outreach 2013: Rwanda.

It has been almost 20 years since the horrific events of the Rwandan genocide. Since that time, the country has made a remarkable recovery owing to good government and a great deal of aid. Health-care services are well organized, but remain short of resources and expertise. Musculoskeletal imaging (and treatment) is in its infancy. Given the huge strides that have been made in social order and stability, there is great hope for the future. It is proposed that future International Skeletal Society (ISS) outreach programs plan to make a meaningful commitment to developing expertise in specific hospitals.

Hip anatomic variants that may mimic abnormalities at MRI: labral variants.

OBJECTIVE: Normal anatomic variants of the acetabular labrum are observed on MR images and include labral variants, several sublabral sulci, and perilabral sulcus. Because variants can be misidentified as labral abnormalities such as labral tears, the radiologist needs to avoid the pitfall of mistaking variants as abnormalities. CONCLUSION: The hip has multiple anatomic variants that can mimic abnormalities at hip MRI. The labrum has several anatomic variants that can be confused with true labral tears.

Hip anatomic variants that may mimic pathologic entities on MRI: nonlabral variants.

OBJECTIVE: The hip has several anatomic variants that may be mistaken for pathologic abnormalities. The radiologist needs to be able to distinguish these variants from true abnormalities. In this review, we present nonlabral variants of the hip that can be seen on MRI. CONCLUSION: The hip has multiple anatomic variants that may mimic disease on hip MRI. Like labral variants, nonlabral variants can be confused for true abnormalities.

High-resolution interleaved water-fat MR imaging of finger joints with chemical-shift elimination.

PURPOSE: To study the use of an interleaved water-fat (IWF) sequence with a custom-made radiofrequency (RF) coil for high-resolution imaging of arthritic finger joints. MATERIALS AND METHODS: High-resolution finger magnetic resonance imaging (MRI) was performed using a custom-made dedicated RF receiver coil and an IWF sequence. A phantom, a cadaver finger specimen, and the fingers of two normal controls and six arthritic subjects were imaged with a resolution of 156 × 156 × 600 µm. The appearance of anatomic structures on the IWF images were compared with images acquired with a regular sequence. The images were reviewed by two musculoskeletal radiologists for the depiction of anatomical structures and for the presence of abnormalities. RESULTS: The high-resolution images revealed detailed structures of the finger joints not detectable using typical clinical resolution. The IWF sequence gave more realistic depiction of subchondral bone thickness, and avoided false bone erosions displayed in the regular sequence. It also allowed better visualization of ligaments and tendons. CONCLUSION: This pilot study shows the feasibility and the potential usefulness of high-resolution IWF imaging for finger joint evaluation. This technique may be useful for the diagnosis and treatment assessment of arthritis, and for the study of joint disease pathogenesis.

Histiocytic Sarcoma Arising From a Long Bone: Report of Two Cases.

Histiocytic sarcoma is a rare, but aggressive malignant neoplasm of monocyte/macrophage lineage with a wide age distribution. Bone involvement is exceedingly rarer compared to the lymph node, skin, and soft tissue, and no long bone involvement has been reported in the English literature. We here report 2 cases of histiocytic sarcoma involving the long bone: one from the femur of a 77-year-old female, status post the placement of an intramedullary nail for subtrochanteric hip fracture; the other from the radius of a 3-year-old female with no significant medical history. Radiologic imaging showed highly destructive lesions in both cases with soft-tissue extension. Microscopy in both cases showed sheets of polygonal mononuclear cells with abundant eosinophilic cytoplasm, prominent nucleoli, and frequent mitosis. Hemophagocytosis were also identified. Immunohistochemistry showed that the lesional cells were strongly diffusely positive for CD68 and CD163. The first patient deteriorated rapidly, despite the aggressive treatment of amputation and chemotherapy. However, the second patient is disease free 36 months post the treatment of amputation only. We conclude that the long bone could be the primary site of histiocytic sarcoma. Its prognosis could be very variable and it is difficult to predict its behavior based on morphological evaluation only.

High-resolution uniform MR imaging of finger joints using a dedicated RF coil at 3T.

PURPOSE: To develop a dedicated radiofrequency (RF) coil for high-resolution magnetic resonance imaging (MRI) of finger joints at 3T to improve diagnostic evaluation of arthritic diseases. MATERIALS AND METHODS: A dedicated cylindrical RF receive coil was developed for imaging finger joints at 3T. A planar coil, a saddle coil, and a 1.5T coil with similar design as the dedicated coil were also constructed to compare imaging performance with the dedicated coil. A phantom was used for quantitative evaluation. Three-dimensional images were obtained on four subjects and a cadaver finger specimen using isotropic resolution of 160 mum in 9:32 minutes. The images were reviewed by two musculoskeletal radiologists. RESULTS: The dedicated finger coil provided higher signal-to-noise and greater signal uniformity than the other coils. It supported high-resolution imaging that demonstrated anatomical details of the entire finger joint, and in the subject study revealed abnormalities not detectable by traditional clinical resolution. CONCLUSION: The dedicated finger coil optimizes the potential advantages of 3T scanners compared to lower field magnets. Use of this coil should facilitate early diagnosis, improve assessment of treatment response, and provide better understanding of basic mechanisms that underlie arthritis.

Diabetic myopathy: MRI patterns and current trends.

OBJECTIVE: This study retrospectively evaluates diabetic myopathy in a large referral hospital population. It describes the MRI findings and the distribution of muscle involvement, including comparison with clinical parameters. MATERIALS AND METHODS: MRI reports of the lower extremities from July 1999 through January 2006 were reviewed and compared with clinical parameters for patients with diabetic myopathy. Clinical parameters (e.g., type of diabetes, hemoglobin A(1C) level, creatine kinase level, and erythrocyte sedimentation rate [ESR]) and the presence of complications, including nephropathy, neuropathy, and retinopathy, were noted. The distribution of muscle involvement and imaging features were reviewed. RESULTS: Over a 79-month period, 21 extremities (11 thighs and 10 calves) of 16 patients were imaged. Fourteen (88%) patients had type 2 diabetes, and two (12%) had type 1 diabetes. Four patients (25%) had disease in more than one location. In the thigh, the anterior compartment was involved in all patients. The posterior compartment was affected in nine (90%) of 10 calves. Muscle infarction and necrosis was seen in eight (38%) extremities. The creatine kinase level, ESR, and hemoglobin A(1C) level were elevated in the majority of cases. Coexisting nephropathy (50%), neuropathy (50%), and retinopathy (38%) were present in these patients. CONCLUSION: Diabetic myopathy may occur more frequently in patients with type 2 diabetes than previously reported. In this population, T2-weighted and contrast-enhanced images have similar findings, and the increased coexistence of nephropathy makes administration of gadolinium-based contrast agents ill-advised. With a typical clinical presentation and MRI findings, a confident diagnosis can be made, and potentially harmful biopsy is avoided. Diabetic myopathy encompasses a spectrum of diseases, including muscle inflammation, ischemia, hemorrhage, infarction, necrosis, fibrosis, and fatty atrophy. It is usually seen with long-standing, poorly controlled diabetes.

Schatzker classification of tibial plateau fractures: use of CT and MR imaging improves assessment.

The Schatzker classification system for tibial plateau fractures is widely used by orthopedic surgeons to assess the initial injury, plan management, and predict prognosis. Many investigators have found that surgical plans based on plain radiographic findings were modified after preoperative computed tomography (CT) or magnetic resonance (MR) imaging. The Schatzker classification divides tibial plateau fractures into six types: lateral plateau fracture without depression (type I), lateral plateau fracture with depression (type II), compression fracture of the lateral (type IIIA) or central (type IIIB) plateau, medial plateau fracture (type IV), bicondylar plateau fracture (type V), and plateau fracture with diaphyseal discontinuity (type VI). Management of type I, II, and III fractures centers on evaluating and repairing the articular cartilage. The fracture-dislocation mechanism of type IV fractures increases the likelihood of injury to the peroneal nerve or popliteal vessels. In type V and VI fractures, the location of soft-tissue injury dictates the surgical approach and the degree of soft-tissue swelling dictates the timing of definitive surgery and the need for provisional stabilization with an external fixator. CT and MR imaging are more accurate than plain radiography for Schatzker classification of tibial plateau fractures, and use of cross-sectional imaging can improve surgical planning.

Pulmonary fat embolism after pelvic and long bone fractures in a trauma patient.

Fat embolism is a common complication of pelvic and long bone fractures. Macroscopic fat emboli in the pulmonary arteries on computed tomography have been reported postoperatively after fixation of long bone fractures for trauma, however the quantification of attenuation values of fat emboli have been infrequently reported in the literature. We present a case of pulmonary fat embolism in a 52-year-old female after acute bony trauma sustained during a motor vehicle accident. To the authors' knowledge however, pulmonary fat embolism has not been described on the initial trauma CT scan.

A Comparative Study of High-Resolution Chemical-Shift-Eliminated Magnetic Resonance Imaging of Finger Specimens with Microcomputed Tomography.

OBJECTIVE: High-resolution images of finger joints with chemical-shift elimination can be obtained using an interleaved water-fat (IWF) sequence. This study assessed IWF imaging of finger joints in the delineation of bone structures by comparing images of cadaver fingers with those of microcomputed tomography (CT) that served as a standard reference. MATERIALS AND METHODS: IWF images with spatial resolution of 176 µ × 176 µ × 300 µ were obtained from the distal and proximal interphalangeal joints of two cadaver finger specimens using a custom-built radiofrequency receive coil at 1.5T. Regular three-dimensional gradient-echo (GRE) images were also acquired with similar parameters and compared with the IWF images to evaluate the effects of chemical shift. Micro-CT scans were obtained and served as the standard reference. The image data were reviewed by two experienced musculoskeletal radiologists in consensus. The delineation of normal joint structures and abnormalities in the finger specimens as revealed by the magnetic resonance imaging (MRI) and micro-CT images were compared. The IWF and regular GRE images were assigned scores 0-3 for the depiction of apparent marginal bone defects, with zero being the same in appearance to the micro-CT image and three as having minimal resemblance to it. Statistical analysis of the scoring results was conducted to compare the two MRI techniques. RESULTS: The high-resolution IWF images provided accurate delineation of bone and calcified structures as seen in micro-CT. The thickness of subchondral bone was depicted similarly on the IWF water + fat and the micro-CT images but not on the regular GRE images. The regular GRE sequence showed false marginal bone defects not observed with IWF and micro-CT. In addition, the IWF water-only images facilitated the identification of bone cyst by revealing its water content. CONCLUSION: High-resolution IWF imaging should be useful for the early diagnosis and treatment assessment of arthritis and should also benefit basic research in the pathophysiology of the disease.

Calcaneal fractures: what the surgeon needs to know.

The calcaneus is an uncommonly fractured bone that plays a critical role in foot biomechanics, weight-bearing, and the ability to wear a shoe. The radiologist acts as a consultant during screening, operative planning, and follow-up imaging of these often complex injuries. Effective communication between radiologist and surgeon requires an understanding of calcaneal anatomy, goals of surgical reduction, and factors that affect patient management and outcomes. In the following pictorial review we will discuss radiologic screening/classification/characterization and their correlation with surgical management and patient morbidity.