Howard J. Ansel

A comparison of colonoscopy and double-contrast barium enema for surveillance after polypectomy

BACKGROUND After patients have undergone colonoscopic polypectomy, it is uncertain whether colonoscopic examination or a barium enema is the better method of surveillance. METHODS As part of the National Polyp Study, we offered colonoscopic examination and double-contrast barium enema for surveillance to patients with newly diagnosed adenomatous polyps. Although barium enema was performed first, the endoscopist did not know the results. RESULTS A total of 973 patients underwent one or more colonoscopic examinations for surveillance. In the case of 580 of these patients, we performed 862 paired colonoscopic examinations and barium-enema examinations that met the requirements of the protocol. The findings on barium enema were positive in 222 (26 percent) of the paired examinations, including 139 of the 392 colonoscopic examinations in which one or more polyps were detected (rate of detection, 35 percent; 95 percent confidence interval, 31 to 40 percent). The proportion of examinations in which adenomatous polyps were detected by barium enema colonoscopy was significantly related to the size of the adenomas (P=0.009); the rate was 32 percent for colonoscopic examinations in which the largest adenomas detected were 0.5 cm or less, 53 percent for those in which the largest adenomas detected were 0.6 to 1.0 cm, and 48 percent for those in which the largest adenomas detected exceeded 1.0 cm. Among the 139 paired examinations with positive results on barium enema and negative results on colonoscopic examination in the same location, 19 additional polyps, 12 of which were adenomas, were detected on colonoscopic reexamination. CONCLUSIONS In patients who have undergone colonoscopic polypectomy, colonoscopic examination is a more effective method of surveillance than double-contrast barium enema.

Variability in measurement of abdominal aortic aneurysms

PURPOSE The purpose of this study was to report interobserver and intraobserver variability of computed tomography (CT) measurements of abdominal aortic aneurysm (AAA) diameter and agreement between CT and ultrasonography observed in the course of a large, multicenter, randomized trial on the management of small AAAs. METHODS CT measurements of AAA diameter from participating centers were compared with measurements made from the same scan by a central laboratory. Blinded central remeasurement of a randomly selected subset of these CT scans was used to assess intraobserver variability. Agreement between AAA measurements by CT and ultrasonography done within 30 days of each other was also assessed. RESULTS For interobserver pairs of local and central CT measurements of AAA diameter (n = 806), the difference was 0.2 cm or less in 65% of pairs, but 17% differed by at least 0.5 cm. For intraobserver pairs of central CT remeasurements (n = 70), 90% differed by 0.2 cm or less, 70% were within 0.1 cm, and only one differed by 0.5 cm. Of 258 ultrasound-measured and central CT pairs, the difference was 0.2 cm or less in 44% and at least 0.5 cm in 33%. Ultrasound measurements were smaller than central CT measurements by an average of 0.27 cm (p < 0.0001). Local CT and ultrasound measurements showed a marked preference for recording by half centimeter. CONCLUSIONS A high degree of precision is possible in CT measurement of AAA diameter, but this precision may not be obtained in practice because of differences in measurement techniques. Differences between imaging modalities increase variability further. Variations in AAA measurement of 0.5 cm or more are not uncommon, and this should be taken into account in management decisions. Efforts to reduce variation in measurement are warranted and might include (1) seeking agreement between surgeons and radiologists on a precise definition of AAA diameter, (2) limiting the number of radiologists who measure AAAs, and (3) use of calipers and magnifying glass for CT measurements.

Relationship of age, gender, race, and body size to infrarenal aortic diameter

PURPOSE To assess the effects of age, gender, race, and body size on infrarenal aortic diameter (IAD) and to determine expected values for IAD on the basis of these factors. METHODS Veterans aged 50 to 79 years at 15 Department of Veterans Affairs medical centers were invited to undergo ultrasound measurement of IAD and complete a pre-screening questionnaire. We report here on 69,905 subjects who had no previous history of abdominal aortic aneurysm (AAA) and no ultrasound evidence of AAA (defined as IAD > or = 3.0 cm). RESULTS Although age, gender, black race, height, weight, body mass index, and body surface area were associated with IAD by multivariate linear regression (all p < 0.001), the effects were small. Female sex was associated with a 0.14 cm reduction in IAD and black race with a 0.01 cm increase in IAD. A 0.1 cm change in IAD was associated with large changes in the independent variables: 29 years in age, 19 cm or 40 cm in height, 35 kg in weight, 11 kg/m2 in body mass index, and 0.35 m2 in body surface area. Nearly all height-weight groups were within 0.1 cm of the gender means, and the unadjusted gender means differed by only 0.23 cm. The variation among medical centers had more influence on IAD than did the combination of age, gender, race, and body size. CONCLUSIONS Age, gender, race, and body size have statistically significant but small effects on IAD. Use of these parameters to define AAA may not offer sufficient advantage over simpler definitions (such as an IAD > or = 3.0 cm) to be warranted.

Clinical and endoscopic findings in patients early in the course of clostridium difficile-associated pseudomembranous colitis

Endoscopic and clinical features are reported for 39 patients detected early in the course of pseudomembranous colitis. Disease was detected early by virtue of careful surveillance in patients in whom diarrhea developed. Early proctosigmoidoscopic findings in pseudomembranous colitis are illustrated. Clinical presentation includes development of fever, leukocytosis, abdominal pain, and even an ileus picture on radiography in addition to diarrhea.

Partial biliary obstruction caused by chronic pancreatitis. An appraisal of indications for surgical biliary drainage.

This paper presents a retrospective review of 38 patients with intrapancreatic bile duct strictures secondary to chronic alcoholic pancreatitis. The strictures were identified by endoscopic retrograde cholangiopancreatography (ERCP). All patients with pancreatic cancer and gallstone pancreatitis were excluded. The mean alkaline phosphatase and total bilirubin values were 344 +/- 57 IU/dl and 4.4 +/- 0.7 mg/dl, respectively. The mean stricture length was 3.9 +/- 0.5 cm, and the mean common bile duct (CBD) diameter was 1.8 +/- 0.2 cm. The degree of bilirubin and alkaline phosphatase elevation did not correlate with stricture length or the severity of bile duct dilatation. Eighteen of the 38 patients received surgical biliary drainage (BD) as part of their initial therapy, and 20 patients did not. Liver function tests, intrapancreatic stricture length, and the degree of proximal CBD dilation were comparable in these two groups. Patients not undergoing BD did well clinically as only one patient required BD over an average follow-up period of 3.8 years. In conclusion, bypass of these strictures is usually unnecessary, and most patients may be safely treated without operation.

Preoperative endoscopic retrograde cholangiopancreatography in the surgical management of pancreatic pseudocysts

Preoperative ERCP was performed on 39 patients treated surgically for pancreatic pseudocysts from 1970 to 1982 at the Minneapolis Veterans Administration Medical Center. ERCP-related sepsis was rare (4 percent of patients) and only occurred when surgery was delayed for more than 24 hours. The primary benefit of preoperative ERCP was to provide detailed information on pancreatic and biliary ductal anatomic characteristics other than those specifically related to the pancreatic pseudocyst. These data influenced the choice of operation in 49 percent of the patients. Specific preoperative surgical planning was facilitated and intraoperative pancreatography and cholangiography were obviated. Major postoperative complications occurred in 21 percent of the patients (0 percent mortality) but none were considered to be related to preoperative ERCP. ERCP before operation is a safe and important adjunct to surgical management of pancreatic pseudocysts. We strongly believe, however, that the interval from ERCP to surgery should not exceed 24 hours.

A comparison of upper gastrointestinal endoscopy and radiography

One hundred symptomatic patients were evaluated independently with upper gastrointestinal radiography and fiberoptic endoscopy, and the results were compared. Of the two endoscopists sequentially examining the same patient, one was informed of available clinical and radiographic details and the other was not. Knowledge of the x-ray examination by the informed endoscopist did not improve his accuracy. Each endoscopist made four errors of interpretation. The endoscopic and x-ray findings agreed in 46 of the 100 patients, most often (68%) in the eophagus, least often (29%) in the stomach and half the time (45%) in the duodenum. Ulcer craters seen endoscopically were detected radio-graphically in 36% of patients. We conclude that: 1) knowledge of results of prior upper gastrointestinal radiography did not alter endoscopic results; 2) experienced endoscopists are accurate but make mistakes; and 3) endoscopic findings would have been unaltered had radiography not been performed.

A randomized blinded comparison of omeprazole and ranitidine in the treatment of chronic esophageal stricture secondary to acid peptic esophagitis

BACKGROUND Esophageal strictures due to gastroesophageal reflux disease are often resistant to medical therapy and require repeated dilation procedures. Our aim was to compare the efficacy of therapy with omeprazole (20 mg/day) to ranitidine (150 mg twice daily) in the treatment of chronic esophageal strictures. METHODS Thirty-three patients with chronic esophageal stricture disease (mean length of prior treatment, 50.9 months) were entered into a randomized blinded trial. The majority (88%) of the patients had received multiple prior esophageal dilations (mean, 7.9 per patient). Endoscopy and barium esophagograms were performed initially and at the end of 10 months. Symptoms were considered every 2 months and dilations performed as needed. The patient groups were equivalent. RESULTS One patient in each group was subsequently lost to follow-up. No significant differences were seen in symptom improvement or need of dilation. At the final endoscopy, 8 of 17 (47%) patients receiving ranitidine had residual erosions or ulceration, compared with 1 of 14 (7%) patients receiving omeprazole (p >0.2). All patients receiving ranitidine had persistent strictures, whereas 8 of 14 (57.1%) patients receiving omeprazole had radiographic and endoscopic resolution of their strictures (p <0.004). CONCLUSION These data further emphasize the need for vigorously treating esophagitis in patients with acid peptic strictures.

Endoscopic retrograde intrahepatic cholangiography in liver diseases

Particular attention to the radiographic characteristics of the intrahepatic bile duct system was directed to a series of 56 patients selected on the basis of having nearly simultaneous endoscopic retrograde cholangiography and liver biopsy. Careful attention to details of the fine ductal configuration may contribute information helpful in resolving the differential diagnosis of intrahepatic disease.

Radiotherapy verification film for estimating cumulative entrance skin exposure for fluoroscopic examinations.

Measurement of skin entrance exposures during fluoroscopic procedures is complicated by the use of automatic exposure control devices and the presence of contrast media. Due to variability in positioning spot films from patient to patient, standard dosimeters, such as thermoluminescent, cannot be properly placed on the skin prior to examination. Prepackaged film of the type used for portal verification in radiation therapy held next to the patients skin in a specially modified patient examination gown was found to be useful for determining the entrance skin exposure from both fluoroscopy and spot films during air contrast barium enema exams. The usable sensitivity range of this film has been found satisfactory for exposure measurements at exposures and kVps typically used for gastrointestinal fluoroscopic procedures. Errors in exposure estimates due to changes in film speed and contrast with kVp are less than 5% for the range of kVps used. Errors from variations in beam quality due to the adjacency of scattering material are approximately 5%. Entrance exposures determined with film agreed with those determined from TLD measurements to within 21%, with an average difference of 9%.