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Biomedical subjects

G W Stevenson

Publications and source records attributed to G W Stevenson.

At least 127 records · Page 7Linked to original sources
PubMed1983

Benign gastric ulcer: a reliable radiologic diagnosis?

A review of 7,600 double-contrast barium-meal studies performed between 1975 and 1981 revealed 221 gastric ulcers reported as benign. The follow-up for 199 of these was adequate and detected no case of carcinoma. The widespread practice of immediate endoscopy and biopsy for all cases of radiologically benign gastric ulcer represents a misuse of expensive medical resources. When a gastric ulcer is demonstrated clearly as benign on double-contrast examination, there is no need for endoscopic confirmation of the diagnosis.

Adult↗
PubMed1983

Distribution of gastric ulcers by double contrast barium meal with endoscopic correlation.

The double contrast barium meals and endoscopic examinations of 246 patients with 264 benign gastric ulcers were reviewed with regard to the location of these ulcers. Seventy-four per cent of ulcers were found in the antral portion of the stomach within 7 cm of the pyloric canal. A similar study in the United Kingdom revealed that the majority of ulcers were in the upper body of the stomach. Since true gastric ulcers almost always arise in a pyloric type of mucosa, or in the zone of transition from pyloric to body type mucosa, perhaps this junction zone lies higher in a United Kingdom population than in North Americans. Possibly the higher transition zone and the documented higher frequency of gastric malignancy in the United Kingdom are related.

Barium Sulfate↗
PubMed1983

Interrelations of the various mathematical approaches to radioimmunoassay.

Equations used for calculation of radioimmunoassay data are derived and compared. We show that the equation developed by Fernandez and Loeb is the most general of these. Those of Ekins et al., Hales and Randle, and Rodbard et al. are all derived here from this basic equation by neglecting certain of its terms. The logit-log plot of Rodbard et al. is a logarithmic transformation of the linear Hales-Randle equation. The basic equation, derived here solely from the mass-action law, approaches linearity under certain conditions without complex mathematical transformations of analyte concentrations or observable parameters. Applications are also presented.

Humans↗
PubMed1982

The colitides.

Diverse signs may be seen on barium enema in the various forms of colitis. Barium enema is only reasonably specific in the diagnosis of Crohn's disease and ulcerative colitis once the other possible diseases have been excluded from consideration by biopsy, microscopy, culture, or therapeutic trial. In particular, campylobacter colitis has proved to be such a common entity that many patients originally thought to have had one attack of ulcerative colitis, ischemic colitis, or Crohn's colitis may never have had these diseases. Many of the relatively specific signs can be seen in a variety of conditions. For example, aphthae in the colon may be seen in Crohn's disease, yersinia enterocolitis, Behçet's syndrome, amebiasis, ischemia, tuberculosis, and campylobacter colitis. Continuity of disease is characteristic in ulcerative colitis. Nevertheless, patches of healing may occur, so that a rare patient may be seen during a resolving attack of ulcerative colitis in whom only scattered patches of active disease can be seen on barium enema. In general, few radiologic signs on barium enema are truly specific for one disease, with penumatosis cystoides coli being an exception to this rule. However, the sensitivity of barium enema with currently available materials for double-contrast techniques is such that radiology continues to be useful at present in diagnosing the colitides and in managing patients.

Adult↗
PubMed1982

Cigarette smoking and duodenal coating with barium.

A review of two hundred and fifty-eight double contrast barium meal examinations was carried out in a single blind study of the relationship between smoking and the ability to visualize gastric and duodenal mucosal detail. A strong correlation was found between poor duodenal visualization and smoking in the period immediately prior to the examination. Patient compliance with a typed instruction sheet forbidding smoking was found to be poor. It may be possible to improve compliance by including, in the written instructions, an explicit statement that smoking shortly before barium meal examination may cause lesions to be missed.

Barium Sulfate↗
PubMed1982

Radiologically assisted endoscopic papillotomy.

Endoscopic sphincterotomy is now established as a safe technique for the treatment of common bile duct stones or papillary stenosis. The procedure is occasionally unsuccessful because of difficulty in cannulation. Two patients are described in whom the presence of a transbiliary drainage catheter facilitated endoscopic sphincterotomy. With such radiologic assistance, there should be few patients in whom the procedure cannot be accomplished.

Aged↗
PubMed1981

Correlation between visualization and size of the areae gastricae and duodenal ulcer.

The relationship between the antral mucosal appearance and the incidence of duodenal ulcer was examined by review of 250 double-contrast barium-meal studies. When the mucosal pattern was seen, the areae gastricae were larger in patients with duodenal ulcer. Failure to see the mucosal pattern occurred more frequently in patients without ulcer.

Adult↗
PubMed1981

Colorectal carcinoma missed on double contrast barium enema study: a problem in perception.

A total of 31 cases of primary colorectal carcinoma missed on double contrast barium enema studies over a 5 year period (1976-1980) were collected from six institutions, and the causes of error reviewed. The errors were purely perceptive in 52%, due to a combination of perceptive and technical factors in 32%, and interpretative in 6%. The most common perceptive mistakes were failure to recognize a filling defect in the barium pool and failure to detect the tumor en face in double contrast study. Five cases were only detected at the time of the study as a result of double reading. Ten percent of the lesions could not be seen in retrospect, and therefore can be attributed to failure of the technique itself. At four of the institutions, the double contrast barium enema study missed 11 (6%) of 197 primary colorectal carcinomas. The lesion was invisible in retrospect in only two (1%) of these 197 studies, indicating that the double contrast examination is potentially highly sensitive for detecting colorectal carcinoma. The mainly perceptive nature of the errors indicates the need for more careful viewing of double contrast barium enemas. Familiarity with the different appearances of colorectal carcinoma on double contrast study, together with double-reading by the same or different observers, should reduce the incidence of missed lesions.

Barium Sulfate↗
PubMed1981

Inaccuracy of radiographic measurements of colon polyps.

Polyp size is one of the main determinants of the surgical management of polyps in areas without colonoscopy services. We reviewed 47 patients with 59 polyps at two hospitals. Polyp dimensions were measured directly from air contrast barium enema radiographs, and again after resection and fixation. In over 95% of polyps the radiographic size exceeded the pathologic size by 10 to 100%. Since surgery may be decided on the basis of polyp size, an inaccurate measurement may result in unnecessary colonoscopy or laparotomy. We therefore recommend a correction factor derived from measuring a rectal tube of known diameter.

Colonic Neoplasms↗
PubMed1981

Evaluation of double contrast barium enemas performed by radiographic technologists.

This study was undertaken to see if radiographic technologists could be trained to perform double contrast barium enemas of a quality comparable to that produced by gastrointestinal radiologists and radiology residents. One technologist was from a remote rural hospital and the other from a university gastrointestinal radiology department. After initial training the two technologists continued to produce work of high quality. Analysis of the films showed that there was no significant difference between those films produced in the rural hospital and in the university centre. We recommend more widespread training of radiographic technologists in this work.

Barium Sulfate↗
PubMed1980

Case report. Calcified gastric duplication.

A case of gastric duplication with dystrophic calcification that was radiographically visible in a 53-year-old female is reported. We could not find any previous similar report in the literature.

Calcinosis↗