Antimicrobial prophylaxis after tick bites.
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Animals↗
Biomedical subjects
D Magid
Publications and source records attributed to D Magid.
Metastatic adenocarcinoma of the prostate: presentation as a pleural-based mass.
We have presented an unusual case of metastatic prostate carcinoma simulating a primary bone tumor. Although previous reports have described periosteal and "pseudosarcomatous" prostate metastases, no report makes reference to rib involvement. Furthermore, the large soft tissue component is highly unusual. This case illustrates that although such lesions are rare, in the older patient, metastases should be included along with primary tumors in the differential diagnosis of a spiculated bone lesion with prominent soft tissue involvement.
Adenocarcinoma↗
Subtle orthopedic fractures: teleradiology workstation versus film interpretation.
The purpose of this study was to evaluate whether radiologists perform equally well with plain radiographs or digitized images displayed on a video monitor in interpretation of difficult orthopedic trauma cases. Interpretations with film and those made from a teleradiology system with spatial resolution of 2.35 line pairs per millimeter were compared in 120 difficult cases, 60 with the selected abnormality (ie, fracture or dislocation) and 60 that were control cases. Seven senior radiology residents and one radiology fellow each interpreted 60 randomly ordered cases with the teleradiology system (1,280 x 1,024-pixel monitors) and 60 cases with the original radiographs. The overall accuracy of the readers was 80.6% for film interpretations and 59.6% for teleradiology screen readings (P < .001). Sensitivity was 78.5% for film and 48.8% for on-screen images (P < .001), and specificity was 83.2% for film and 72.3% for on-screen images (P < .025). Receiver operating characteristic analysis showed rejection of the null hypothesis in favor of film interpretation (P < .0049). It was concluded that the teleradiology system was not acceptable for primary diagnostic interpretation of difficult fracture cases.
Computer Terminals↗
Two-dimensional and three-dimensional computed tomographic imaging in musculoskeletal tumors.
Appropriate treatment of musculoskeletal neoplasms relies on prompt and accurate identification of tumor characteristics and extent. Multiplanar and three-dimensional (3-D) computed tomography (CT) provide rapid, relatively noninvasive imaging for initial assessment and for planning of radiation therapy, en bloc resection, and limb-salvage surgery. An integrated 2-D-3-D CT approach also allows precise tracking of therapeutic response and recurrence.
Bone Neoplasms↗
Prevention of Lyme disease after tick bites. A cost-effectiveness analysis.
BACKGROUND: In areas of endemic disease, the probability of Lyme disease after a tick bite ranges from about 0.012 to 0.05. Early treatment with oral antibiotics prevents most complications of Lyme disease, but antibiotics are generally not prescribed until rash or other symptoms develop. METHODS: We used decision analysis to evaluate the outcomes, costs, and cost effectiveness of three alternative strategies to treat patients bitten by ixodes ticks in areas of endemic Lyme disease: empirically treat all patients with two weeks of doxycycline, treat only patients in whom erythema migrans develops, and treat only patients with erythema migrans or a positive serologic test for Lyme disease one month after exposure. RESULTS: Empirical treatment is the least expensive strategy and results in the fewest cases of Lyme disease and the fewest complications when the probability of Borrelia burgdorferi infection after a tick bite is 0.036 or higher. For probabilities of infection below 0.036, empirical therapy prevents most major complications, sequelae, and adverse events, but it incurs additional minor complications, especially as the probability of infection falls below 0.01. CONCLUSIONS: Empirical treatment of patients with tick bites is indicated when the probability of B. burgdorferi infection after a bite is 0.036 or higher, and this treatment may be preferred when the probability of infection ranges from 0.01 to 0.035. When the probability of infection after a tick bite is less than 0.01, empirical therapy is not warranted.
Animals↗
Examination of the pathologic anatomy of ankle fractures.
A prospective study of the translational and rotational displacement of the lateral malleolus in ankle fractures was carried out utilizing roentgenographic techniques. Twenty-six ankle fractures in 25 patients were studied using both routine plain films and CT scanning with two- and three-dimensional multiplanar reconstruction. Eighty-one percent were Lauge-Hansen supination-external rotation type injuries. Overall, 21 fractures did not involve the medial malleolus. Initial talar shift was less than or equal to 2 mm in 15 fractures. Although all patients exhibited external rotation deformities of the lateral malleolus on plain films, only one fracture was found to possess any degree of external rotation relative to the talus. The proximal fibula was seen on CT scans to have increased internal rotation with respect to the tibia in 19 cases. One patient had a slightly externally rotated proximal fibula; the remainder appeared normally aligned. The displacements measured by the CT scans at the talofibular articulation were compared with the standard plain film measurements. The displacements at the distal lateral malleolus were consistently overestimated by the plain roentgenograms, presumably because the capsular and ligamentous attachments to the distal fibula limit malleolar displacement. The talocrural angle, determined on both plain films and CT scans, was also not found to be a sensitive measure of fibular shortening nor of the severity of the fracture. The results of this study suggest that, in an isolated lateral malleolar ankle fracture, the apparent external rotation of the fracture fragment is relative only to the proximal fibula and is not associated with derangement of the talofibular articulation. Based on these mechanical considerations, surgical intervention for such fractures may not be necessary. This hypothesis is consistent with previous long-term clinical studies.
Adolescent↗
Musculoskeletal infections in patients with AIDS: CT findings.
The CT appearances of various musculoskeletal infections found in patients with AIDS are illustrated. Recognition of these infections is important for management of patients, but conventional laboratory tests may be inadequate in screening for infection or confirming the response of the host to therapy. As a screening examination for patients with AIDS, CT can suggest or confirm the presence of musculoskeletal infections even when infection has not been suspected.
Abscess↗
Aneurysmal bone cyst developing after anterior cruciate ligament tear and repair.
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Adult↗
Lymphoma of bone, muscle, and skin: CT findings.
Lymphoma can involve any part of the musculoskeletal system. Primary musculoskeletal lymphoma is rare but can occur in bone (reticulum cell sarcoma) or in the skin and subcutaneous tissues (mycosis fungoides). Secondary involvement in the musculoskeletal system is more common and can have a variety of radiologic findings. The definitive diagnosis of musculoskeletal lymphoma, however, is difficult to make by using imaging criteria alone. Any part of the musculoskeletal system can be involved and, therefore, a wide variety of primary and secondary neoplasms or inflammatory processes may have similar radiologic findings. The main differential diagnostic considerations, depending on the age of the patient and the clinical presentation, include osteosarcoma, Ewing's tumor, metastatic disease (from breast, lung, thyroid, or renal primary lesions), as well as chronic osteomyelitis or myositis. Primary and secondary bone lymphoma can be indistinguishable radiologically and histologically, but modern imaging techniques allow more accurate differentiation of primary from secondary bone involvement. This pictorial essay illustrates the CT findings of primary and secondary lymphoma involving bone, muscle, and skin and subcutaneous tissues.
Bone Neoplasms↗
Cryptococcus neoformans osteomyelitis of the clavicle.
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Cryptococcosis↗
Preoperative interactive 2D-3D computed tomography assessment of heterotopic bone.
Total hip arthroplasty is a common orthopaedic procedure in this country. Postoperative heterotopic bone formation may be seen in anywhere from 5% to 76% of such procedures. Only a small subgroup of these patients are symptomatic. Approximately 6% of arthroplasty patients require evaluation of heterotopic bone. In such patients, computed tomography may be useful in staging the extent of bone formation and in helping to plan surgical or radiotherapy treatment. Reformatting transaxial data into coronal and sagittal planar images and into simulated three-dimensional images provides the most comprehensive overview and maximizes communication of relevant findings.
Adult↗
Pulmonary Aspergillus chest wall involvement in chronic granulomatous disease: CT and MRI findings.
Pulmonary Aspergillus infection in patients with chronic granulomatous disease tends to involve the chest wall and consequently carries a high mortality rate. We report the findings of computed tomography (CT) and magnetic resonance imaging (MRI) in three such cases. One patient underwent both CT and MRI, one, CT only, and one, MRI only. In all three, both CT and MRI demonstrated pulmonary consolidations with direct extension to the adjacent chest wall. In both patients who were examined by CT, scans revealed permeative osteolytic changes of adjacent rib or spine compatible with osteomyelitis. In both patients who were examined by MRI, adjacent chest wall involvement was depicted on T1-weighted images and showed increased signal intensity on T2-weighted images. In one of these patients, the chest wall lesion was well defined on T2-weighted images, an appearance compatible with abscess. Epidural extension was demonstrated on MRI in the other patient, who later developed paraparesis. We suggest that CT and MRI have a complementary role in evaluating chest wall invasion by pulmonary Aspergillus infection in chronic granulomatous disease.
Adolescent↗
The use of graphic design in an interactive computer teaching program.
The widespread diffusion of affordable computers into the scientific and educational community has provided the opportunity to design medical and scientific teaching programs illustrated either by hand or by utilizing commercially available software and manipulating existing computer generated images. The medical illustrator can provide the ideal aesthetic link between text format information and the visual representation of such knowledge in a concise presentation format. The availability of interactive multimedia programs has given the medical illustrator an environment to create and enhance Hypermedia designed specifically for the purpose of medical education. This paper will focus on the incorporation of illustration and screen design into "CT The Game," an experimental medical teaching program currently being developed in the Johns Hopkins Body CT Imaging Laboratory. The program is designed to provide an enjoyable approach to learning Computed Tomography (CT), and is directed toward an audience of medical students, residents, and fellows.
Computer Graphics↗
Data base management in radiology: a simplified approach.
The increasing availability of personal and departmental computers in radiology departments has led to increasing interest in data management. Data base management software must be system compatible, simple, and flexible to insure its acceptance and constant use. Once in place, such a system streamlines the daily documentation of interesting cases for conference, follow-up, research, and quality assurance. The authors have developed such a data base program for tracking computed body tomography cases in their department, which can be run as a portable computer to maximize ease of access and therefore usage.
Database Management Systems↗
The perception of mirror-reflected objects.
In what ways and under what conditions does an object appear to differ from its enantiomorph (its mirror reflection)? This 'mirror question' or its popular counterpart, "Why does a mirror reverse left and right but not up and down?" is frequently encountered, but an acceptable answer is not to be found in the literature. The question is approached as an experimental problem in visual psychophysics. A mirror optically reverses the axis perpendicular to its surface. What are the perceptual consequences of this stimulus transformation? This question is examined in four experiments by using stimuli of varying complexity and familiarity. Apparent reversals are demonstrated along right-left, front-back, top-bottom, and oblique axes, depending on the perceived asymmetries of the stimulus object. Perceived asymmetry is shown to depend both on structural asymmetries and on canonical axes and orientations defined by social convention. It is concluded that an object appears to differ from its enantiomorph by an apparent reversal along the axis of least perceived asymmetry. Implications for perceptual frames of reference and for the perception of symmetry are discussed.
Adult↗
Sacral foramina: view at CT.
Conventional transaxial computed tomography (CT) is superior to plain radiography in depicting the sacrum. Because of the shape and orientation of the sacrum, CT provides oblique views of the structures of interest. With easily reproducible landmarks and standard transaxial CT data, orthogonal image sets can be produced that provide a true en face orientation matching the obliquity of the sacrum. This allows optimal visualization of the paired foramina and of the sacroiliac joints for better assessment of trauma, tumor, or inflammatory disease.
Humans↗
Three-dimensional imaging.
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Bone and Bones↗
Computed tomography of the hand and wrist.
CT plays a limited but distinct role in the evaluation of the hand and wrist. It is most useful in assessing bone and joint anatomy and has only a secondary role in soft tissue abnormalities. The clearest value of CT is in assessing trauma and post-traumatic complications, such as malunion, nonunion, or avascular necrosis, where careful attention to position and technique can yield important information not otherwise obtainable.
Fractures, Bone↗