Evaluation of tibial plateau fractures: efficacy of MR imaging compared with CT.

OBJECTIVE: CT is often used after plain films to evaluate fractures of the tibial plateau. Because MR imaging can show associated soft-tissue injuries as well as fractures, we hypothesize that MR is superior to CT for imaging these injuries. Accordingly, we compared the efficacy of MR imaging and CT in 22 patients with tibial plateau fractures. SUBJECTS AND METHODS: CT with two-dimensional reconstruction and MR examinations were performed in 22 patients with tibial plateau fractures. The images were interpreted by four radiologists and two orthopedic surgeons. Findings on CT scans and plain films were used to determine the configuration of the fractures and to classify them according to the Schatzker system. This was done with findings on MR images and plain films at a separate session. The MR images were also evaluated for ligamentous and meniscal injuries. A qualitative side-by-side comparison of two-dimensional CT scans and MR images for depiction of fracture configuration was done. Imaging results were correlated with observations from physical examinations in all patients and with surgical findings in 12 patients. RESULTS: All of the six types of fractures of the Schatzker classification were observed in this series. Comparison of two-dimensional CT reconstructions and MR images for depiction of fracture configuration revealed that the two techniques were equal in 14 patients, MR imaging was superior to CT in five patients, and CT was superior to MR imaging in three patients (who had very complex and comminuted fractures). In addition, MR imaging showed 12 complete ligamentous tears and 15 partial ligamentous tears in 15 (68%) of the 22 patients. MR showed meniscal injuries in 12 (55%) of the 22 patients. CONCLUSION: MR imaging was equivalent or superior to two-dimensional CT reconstruction for depiction of fracture configuration in most patients. In addition, MR showed significant soft-tissue injuries. We believe that MR imaging is the preferable imaging technique for most patients with fractures of the tibial plateau.

Gastrointestinal radiology: current indications and referral patterns.

To determine the current indications and referral patterns for routine gastrointestinal radiology examinations, 1000 consecutive patients were prospectively analyzed. The following specialties were the largest sources of referral: general internal medicine (38%), gastroenterology (21%), and general and colorectal surgery (17%). Referrals from gastroenterologists were weighted toward areas not well evaluated by endoscopy, such as suspected small bowel disease. The major indications for upper gastrointestinal (GI) examinations were dysphagia and swallowing disorders (32%), hiatus hernia/reflux (14%), and ulcer (14%). Small bowel series were predominantly performed for inflammatory bowel disease (37%), obstruction (25%), and occult blood loss (18%). The majority of combined upper GI/small bowel studies were performed for indications primarily relating to the small bowel. Forty percent of barium enemas were performed for detection of neoplasms and polyps, with pain/irritable colon (14%) and exclusion of leak (14%) the next most common indications. Traditional indications, such as peptic ulcer disease and neoplastic disease, continue to be sources of referral for gastrointestinal radiology. However, more specialized applications, particularly in areas not well suited to endoscopy, such as swallowing disorders, inflammatory disease of the small bowel, and evaluation of surgical anastomoses, are also being commonly used. The changing indications, along with the previously documented decreased volume of gastrointestinal radiologic procedures, should be kept in mind when planning a radiology resident educational curriculum.

CT of pseudohydronephrosis: hydroureter in a weight lifter.

A case of bilateral pseudohydronephrosis and hydroureter produced by markedly hypertrophied psoas muscles in a weight lifter is presented. Plain film and CT findings of the case are discussed together with the topographic anatomical explanation of the radiologic findings.

Paranasal sinuses: low-dose CT.

While computed tomography (CT) has become an important imaging modality in the evaluation of the paranasal sinuses, the radiation dose remains higher than is necessary. With use of a head phantom and constant kilovolt peak setting, axial and coronal CT scans of the paranasal sinuses were obtained at each of six successively lower milliampere second settings than are commonly used in clinical practice. Although noise, as measured by the standard deviation of the CT numbers, did increase, images were of diagnostic quality even when dose levels were reduced by a factor of 28. In the same incremental manner, the milliampere second settings used in scanning 90 patients were reduced, with no loss of diagnostic quality. The authors discuss the methods of analysis and the advantages of use of lower milliampere second settings at CT scanning of the sinuses.

Value of increasing film processing time to reduce radiation dose during mammography.

We systematically tested the effects on radiation dose and image quality of increasing the mammographic film processing time from the standard 90 sec to 3 min. Hurter and Driffield curves were obtained for a Kodak Min-R-OM1-SO177 screen-film combination processed with Kodak chemistry. Image contrast and radiation dose were measured for two tissue-equivalent breast phantoms. We also compared sequential pairs of mammograms, one processed at 90 sec and one at 3 min, from 44 patients on the basis of nine categories of image quality. Increased processing time reduced breast radiation dose by 30%, increased contrast by 11%, and produced slight overall gains in image quality. Simple modifications can convert a 90-sec processor to a 3-min unit. We recommend that implementation of extended processing be considered, especially by those centers that obtain a large number of screening mammograms. Three-minute film processing can reduce breast radiation dose by 30% and increase contrast by 11% without compromising image quality.

Anterior segment upper lobe tuberculosis in the adult. Occurrence in primary and reactivation disease.

Nine patients with pulmonary tuberculosis involving predominantly or exclusively the anterior segment of one or both upper lobes were seen over a five-year period. The incidence of anterior segment upper lobe tuberculosis was 6.3 percent of 142 patients presenting with pulmonary tuberculosis during the same time period. Five of the nine patients with anterior segment upper lobe involvement had reactivation disease. An increased incidence of advanced age, diabetes, associated malignant neoplasms, alcoholism, and steroid use were noted in those patients with anterior segment involvement, although only the occurrence of diabetes was statistically significant. We suggest vigilance with regard to the diagnosis of tuberculosis in patients who are elderly, diabetic, or alcohol abusers, particularly where the roentgenographic appearance of anterior segment upper lobe involvement would tend to favor an alternative diagnosis.

Computed tomographic diagnosis of left innominate vein aneurysm mimicking an anterior mediastinal mass on plain films: a case report.

A case of innominate vein aneurysm producing a discrete mass on lateral chest radiographs is presented. Its radiographic appearance based on its venous position and the role of CT in accurate evaluation are discussed.

Regional alveolar damage (RAD). A localized counterpart of diffuse alveolar damage.

Diffuse alveolar damage (DAD) is usually considered a generalized lung process. During five years the authors observed 83 patients with generalized DAD in 827 adult autopsies (10.1%) and 10 patients with identical, but localized, lesions. The authors propose the term regional alveolar damage (RAD) to designate localized "DAD." RAD was unilateral in six patients and most frequently involved the upper lobe. All ten patients had chronic systemic diseases and presented with life-threatening illnesses. The probable causes of RAD were multifactorial and included hypotensive shock, septicemia, pneumonia, hyperoxia, and pancreatitis. All patients developed respiratory failure, requiring supplemental oxygen and, in nine patients, mechanical ventilation. Chest roentgenograms revealed alveolar or combined alveolar and interstitial infiltrates that corresponded to the lesions found at autopsy. The reasons for localization of RAD within the lung are unclear, but the presence of proliferative lesions and frequent involvement of the upper lobe suggests that RAD is not simply an early phase of DAD and implicates additional pathogenetic factors.

Role of abdominal CT, when available in patients' records, in the evaluation of degenerative changes of the sacroiliac joints.

To determine the role of abdominal computed tomography (CT) that had been performed for other reasons, in the evaluation of degenerative changes of the sacroiliac joints, the authors performed a retrospective review of the sacroiliac joints of 100 patients, all of whom had an abdominal CT scan and a plain abdominal and/or pelvic roentgenogram in their files. The results indicate that, when available in the patient's record, abdominal CT scans provide substantial additional information in the evaluation of degenerative changes of the sacroiliac joints at no extra cost. The authors' results also suggest that after the age of 55, the patient's age does not seem to influence the extent of sacroiliac joint narrowing, which does appear to be affected by the presence of coexisting diffuse idiopathic skeletal hyperostosis.

Double cortical line in the acetabular roof: a sign of disuse osteoporosis.

A double cortical line (DCL) was observed in the acetabular roofs during interpretation of the abdominal radiographs and intravenous pyelograms of patients with paraplegia and quadriplegia. This was investigated by review of the radiographs of 40 paralyzed patients, by postmortem radiographic and histologic examination of the acetabula of one quadriplegic and three nonparalyzed patients, and by observation of the subchondral cortices of various long bones on radiographs of paralyzed and nonparalyzed patients. The DCL resulted from intracortical bone loss caused by severe disuse osteoporosis. It was most prominent in the acetabulum and most frequently found in patients with paraplegia or quadriplegia. The DCL also occurred in other bones, however, and in other conditions associated with severe disuse osteoporosis.

Cardiac pathology in schistosomal cor pulmonale correlated with chest roentgenographs; a case report.

Case report of a 31-year-old male patient from Puerto Rico. Authors report chronic schistosomal cor pulmonale in which the roentgenographic appearance of the heart is correlated with the pathological description of marked dilatation and hypertrophy of the pulmonary conus and infra-conal area. This case report demonstrates the extent of conal dilatation which can be visualized on chest X-ray.

Involvement of the mandibular canal: early sign of osteogenic sarcoma of the mandible.

A case of osteogenic sarcoma of the mandible is presented. The most striking radiologic finding in this case was irregular widening of the mandibular canal, with areas of narrowing and loss of fine parallel cortical margins of the walls of the canal. These changes were accompanied by widening of the periodontal membrane of the adjoining teeth, an early sign of osteogenic sarcoma described by Garrington and colleagues, and loss of lamina dura of the same teeth and one additional adjacent tooth.