Biomedical subjects

S W Medwid

Publications and source records attributed to S W Medwid.

3 recordsLinked to original sources

PubMed1996

Detection of intestinal ischemia in patients with acute small-bowel obstruction due to adhesions or hernia: efficacy of CT.

OBJECTIVE: The purpose of this study was to determine whether CT can be used to diagnose ischemia of the small intestine in patients with small-bowel obstruction due to adhesions or hernia. SUBJECTS AND METHODS: During a 12-month period, 60 patients underwent surgery for complete or high-grade small-bowel obstruction due to adhesions or hernia, and 29 (48%) had evidence of associated intestinal ischemia. All of these patients had been preoperatively diagnosed by CT as having high-grade small-bowel obstruction. At the same time, a prospective determination was made based on the CT as to whether there was any associated intestinal ischemia. All CT scans were performed within 24 hours of the operation. A CT diagnosis of ischemia was based on the presence of two or more of the following signs: bowel-wall thickening, high attenuation of the bowel wall on unenhanced CT scans, mesenteric edema or fluid, asymmetric bowel-wall enhancement on i.v. contrast-enhanced CT scans, pneumatosis, or portal venous gas. Results of the CT examination and surgical findings were then compared. Further evaluation was done with a retrospective multivariate discriminant analysis. RESULTS: Ischemia was prospectively diagnosed on the basis of CT findings in 41 (68%) of the 60 patients. There were no false-negative CT diagnoses (sensitivity, 100%); however, there were 12 CT diagnoses that were false-positive (specificity, 61%). The multivariate analysis corroborated the prospective results by showing high sensitivity (90%) and diminished specificity (50-64%). Bowel-wall thickening and high attenuation of the bowel wall were the most important signs of ischemia on unenhanced CT scans, whereas abnormal bowel-wall enhancement and mesenteric fluid correlated best on enhanced CT examinations. CONCLUSIONS: CT is a sensitive but not completely specific preoperative indicator of intestinal ischemia in patients with small-bowel obstruction due to hernias or adhesions.

Acute Disease↗

PubMed1994

CT of small-bowel obstruction: value in establishing the diagnosis and determining the degree and cause.

OBJECTIVE: The early diagnosis of small-bowel obstruction is critical in preventing complications, particularly strangulation. Traditionally, the clinical diagnosis of small-bowel obstruction has depended on plain film confirmation. Unfortunately, findings on the plain film may not be confirmatory in 20-52% of cases. The purpose of this study was to determine whether CT is superior to the traditional clinical-radiographic evaluation in prospectively establishing the diagnosis, severity, and cause in cases of suspected obstruction of the small bowel and to see what impact this information might have on treatment, costs, and the need for additional gastrointestinal contrast studies. SUBJECTS AND METHODS: Physicians from three surgical services referred all patients with suspected small-bowel obstruction for plain film and CT evaluation. Eight-five patients were evaluated on 90 occasions during an 11-month period. Obstruction was classified on the basis of clinical and plain film findings as absent, indeterminate, or present (partial or complete). CT scans were obtained in all patients and were interpreted and graded without knowledge of the clinical-radiographic classification. The results of gastrointestinal contrast studies (barium enema, small-bowel series, and enteroclysis) performed in 21 cases were also compared. The gold standard for the diagnosis was surgical findings in 61 cases and clinical course in 29 cases. RESULTS: On the basis of the combined clinical-radiographic findings, the diagnosis was complete obstruction in 21 of 46 cases (sensitivity, 46%; confidence interval (CI), 32-60%). When CT was used, the diagnosis was established in all 46 cases (sensitivity, 100%; CI, 86-100%). In the 25 cases in which the traditional evaluation failed, the early CT diagnosis of complete obstruction prevented a 12-72 hr delay in surgery with its attendant increased morbidity, mortality, and costs. On the basis of the combined clinical-radiographic findings, partial obstruction of the small bowel was diagnosed in six of 20 cases (sensitivity, 30%), whereas all cases were detected with CT. False-positive CT findings for complete obstruction of the small bowel occurred in three cases of paralytic ileus (one each due to small-bowel infarction, lower lobe pneumonia, and peritonitis due to rupture of the urinary bladder). One case of colonic obstruction due to carcinoma in the hepatic flexure was mistakenly diagnosed as partial obstruction of the small bowel. The clinical and plain film evaluation was never precise enough to provide the exact location or cause of small-bowel obstruction. Gastrointestinal contrast studies provided additional useful information regarding colonic abnormalities (four cases), functional grading of partial obstruction of the small bowel (six cases), and exclusion of a false-positive CT diagnosis of complete obstruction in a case of reflex ileus. CONCLUSION: CT is sensitive for diagnosing complete obstruction of the small bowel and for determining the location and cause of obstruction. In comparison, the traditional clinical and plain film evaluation is relatively insensitive. CT should be used when the results of clinical and plain film evaluation are inconclusive. Gastrointestinal contrast studies play an important diagnostic role in partial obstruction of the small bowel and in colonic obstruction with predominant small-bowel dilatation.

Humans↗

PubMed1991

Bowel obstruction: evaluation with CT.

Eighty-four computed tomographic (CT) scans from patients referred for bowel obstruction between January 2, 1988, and December 31, 1989, were retrospectively evaluated. A pair of radiologists without knowledge of patient histories determined the presence or absence of bowel obstruction. Sixty-four patients ultimately proved to have intestinal obstruction, and 20 did not. Diagnosis was established by means of surgery (n = 39), barium studies (n = 17), and clinical course (n = 28). Causes of obstruction included adhesions (n = 37), metastases (n = 6), primary tumor (n = 7), Crohn disease (n = 4), hernia (n = 3), hematoma (n = 2), colonic diverticulitis (n = 2), and other (n = 3). In addition, 83 CT examinations in patients with no history or indication of intestinal obstruction were simultaneously reviewed. The overall sensitivity was 94%, specificity was 96%, and accuracy was 95%. The cause of obstruction was correctly predicted in 47 of 64 cases (73%). Intestinal obstruction was not diagnosed in any of the 83 control patients. CT is most useful in patients with a history of abdominal malignancy and in patients who have not been operated on and who have signs of infection, bowel infarction, or a palpable abdominal mass.

Barium Sulfate↗