Septic arthritis.

Diagnosis of septic joint can be a problem for both the clinician and the imager. The longer the delay in diagnosis of a septic arthritis, the greater the chance of significant complication. Many imaging modalities are available to the imager and each plays a definite role. In determining the modality of choice, one should choose what is most efficacious for the individual patient.

Plasma cell tumors with calcified amyloid deposition mistaken for chondrosarcoma.

PURPOSE: To report cases of plasmacytoma with a radiologic appearance simulating that of chondrosarcoma. MATERIALS AND METHODS: The authors describe four cases of plasma cell tumors with scattered foci of calcification within their matrix, causing them to resemble chondrosarcoma radiographically. Histologic examination was performed in three of these cases. RESULTS: Biopsy specimens demonstrated that the calcification in these tumors was contained in areas of amyloid deposition. Although amyloid formation in association with plasma cell dyscrasias is well known, sufficient calcification within the amyloid to become radiographically identifiable has only rarely been reported. CONCLUSION: Calcification in amyloid produced by plasma cell tumors may at times simulate the appearance of chondrosarcoma.

Radiographic assessment of disease progression in rheumatoid arthritis.

The role that radiography plays in the assessment of disease has been a subject of controversy over the last two decades. Significant problems continue to exist with radiographic assessment. These include (1) technical variables, (2) interpretational variables, (3) clinical variables, and (4) pathophysiologic variables. Unless these problems are recognized and fully understood by the interpreting physician, the "gold standard" quickly can become "fool's gold."

Case report 653: Arthritis of the wrist due to Mycobacterium avium-intracellulare.

We present a case of arthritis of the wrist in an elderly man due to Mycobacterium avium-intracellulare. Prior steroid injections and a surgical procedure on the affected wrist were predisposing risk factors for subsequent mycobacterial involvement of the skeleton. Radiographs demonstrated findings characteristic of tuberculous arthritis: particularly, osteopenia with marginal erosions and diffuse lytic lesions involving the carpals, proximal metacarpals, and distal ends of the radius and ulna. MR scans showed soft-tissue involvement and extensive marrow replacement consistent with infection. It is to be reemphasized that the clinical and radiological findings in this case are very often indistinguishable from TB. The diagnosis depends on the results of tissue culture. Since radiologists are likely to be involved increasingly in interpreting images of immunocompromised patients afflicted with a variety of both typical and atypical infections, it is important occasionally to report rare infections such as that described herein.

Imaging of hip disorders.

Many different imaging modalities are available to assist in the evaluation of hip disease. One must choose the image or series of images that not only provide the most diagnostic and clinical information, but also remain the simplest and most cost effective for the patient. The initial examination should be the conventional radiograph. This will provide, in most instances, the most diagnostic information for arthritic disease, stress and insufficiency fractures, infection, and bone tumors. If the conventional radiograph is normal, or if more information is needed, bone scintigraphy should be done next. Bone scintigraphy will confirm the presence of disease, demonstrate its anatomic location, and give some information as to its physiologic state. Computed tomography does not play an important role in the evaluation of hip disease except in acute fractures involving the acetabulum. MR imaging is the modality of choice for diagnosing and staging osteonecrosis, searching for marrow disease, assessing cartilage abnormality, and evaluating the extent of soft-tissue disease.

Appendicular arthropathy.

The radiographic examination plays an extremely important role in the diagnosis of appendicular arthropathies. Accurate diagnosis can be made by observing the radiographic abnormalities in the bones surrounding the joint involved and the distribution of the abnormalities within the joint or the body.

The frequency and diagnostic significance of periostitis in chondroblastoma.

A study was performed to determine the frequency of periosteal reaction associated with chondroblastoma, to investigate the underlying pathophysiology of the periosteal reaction, and to postulate the clinical importance of this radiographic observation. Two hundred fourteen histologically proved chondroblastomas were reviewed and observed for the presence or absence of periosteal reaction and for radiographic changes that might explain the cause of the periosteal reaction. A similar review was performed on 30 other epiphyseally centered lesions of various causes. A distinctive thick, solid periosteal reaction distal to the chondroblastoma was present in 47% of all chondroblastomas and 57% of chondroblastomas present in long bones (excluding the greater trochanter). No periosteal reaction was observed in any of the 30 epiphyseally centered lesions of other causes. When available for observation, plain films showed inflammatory changes in the joint surrounding the chondroblastoma, bone scintigraphy showed tracer uptake similar to that observed in inflammatory lesions and aggressive neoplasms, and MR images showed change in the marrow surrounding the chondroblastoma consistent with edema. This suggests an inflammatory reaction to the chondroblastoma, rather than mechanical stress across a weakened epiphysis, as the cause of the periostitis. We conclude that frequently the chondroblastoma produces a distinctive thick solid or layered periosteal response distant from the lesion along the diametaphyseal shaft. Observation of this unique periosteal response may help to distinguish chondroblastoma from other epiphyseally centered lesions.

Osteoid osteoma of the elbow. A review of six cases.

Six cases of osteoid osteoma of the elbow were reviewed to determine the spectrum of clinical, pathologic and radiologic findings. Since osteoid osteoma of the elbow may masquerade as a nonspecific synovitis, the diagnosis is challenging and frequently delayed. The histology is, however, indistinguishable from that of osteoid osteoma occurring in typical locations. The radiologic features of osteoid osteoma of the elbow include the following triad: (a) osteosclerosis, usually a dominant feature at initial imaging and typically enveloping the nidus; (b) joint effusion; and (c) periosteal reaction that can involve both the bone in which the osteoid osteoma arises and adjacent bones. Awareness of these features will facilitate correct diagnosis, thereby facilitating timely and appropriate treatment.

Soft-tissue masses: diagnosis using MR imaging.

The MR images of 112 soft-tissue masses of various causes were retrospectively reviewed. Pathologic diagnosis by biopsy was available in 96 cases. Diagnosis in the remaining 16 cases was established by characteristic radiographs, CT scans, and/or arteriograms, in conjunction with appropriate history and clinical follow-up. All masses were evaluated with both T1-weighted, 300-600/20-30 (TR/TE), and T2-weighted, 2000/80-100, images. They were reviewed to determine (1) if these images were sufficiently unique to allow a preoperative diagnosis based exclusively on the MR appearance and (2) if benignity vs malignancy could be predicted on the basis of the analysis of the MR image characteristics of the lesion. Concerning the latter, attention was directed to the margins of the lesions, to the impact of the lesion on the surrounding tissues (edema, infiltration, etc.), and to the intensity and homogeneity of the MR signal of the lesion. MR images were sufficiently characteristic to allow a specific diagnosis in 27 (24%) of the 112 cases (10 lipomas, eight hemangiomas, six pigmented villonodular synovitis, two hematomas, and one arteriovenous malformation). MR was incapable of reliably distinguishing between benign and malignant soft-tissue tumors.

Selecting radiology resident candidates.

Radiology resident candidate selection has become a burdensome, subjective, and somewhat arbitrary process. Because the luxury of many well-qualified candidates exists, there is an obligation to select them as honestly, equitably, and objectively as possible. Two years were spent in revising and modifying the resident selection process to make it more uniform and more efficacious. An application scoring form was devised to extract uniform pertinent information from the original application form. Candidates could then be ranked according to a numerical score derived from the form. This allowed easy selection of top candidates to be interviewed. A new interviewing scoring form was developed to include desirable characteristics of resident candidate performance. This form was also devised in such a way as to be easily scored and to allow selection of the top 20 to 25 candidates. These candidates were then ranked by participating faculty members while reviewing their application score forms and their interview forms. Positions for the residency training program were offered according to the ranking. The usefulness of both new forms was evaluated and confirmed by correlating form scores with faculty ranking of academic performance of current residents in the training program.