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Bret T Petersen

Publications and source records attributed to Bret T Petersen.

14 recordsLinked to original sources
PubMed2003

Virtual colonoscopy.

Explore the source record for details and available documents.

Colonography, Computed Tomographic↗
PubMed2003

Development of a swine model for benign stenosis of the bile duct by endoscopic application of intraluminal thermal injury.

BACKGROUND: A simple animal model is desirable for the study of endoscopic therapies used in the management of biliary strictures. The aim of this study was to identify a method for inducing benign biliary stenoses in a porcine model by using endoscopic techniques. METHODS: Endoscopic retrograde cholangiography was performed in 9 swine. Intraluminal injury was applied to the common hepatic duct with graded applications of either a heat probe or a multipolar probe. Cholangiography was repeated at 7-day intervals. If a stricture was not identified by 28 days, injury was created at another site in the common hepatic duct by using a higher energy dose. After a stricture was identified, the animal was killed and bile duct samples were obtained for histopathologic evaluation. RESULTS: Thirteen thermal injuries were created in the 9 animals. Six of 7 heat probe treatments and 1 of 6 multipolar probe treatments resulted in a stricture (p = 0.025, Fisher exact test). Applications of the heat probe at 10 or 15 J produced a stricture in 6 of 6 cases. All strictures were indistinguishable histopathologically from benign strictures in humans. CONCLUSIONS: The application of intraluminal thermal injury with a heat probe results in a reproducible animal model of benign biliary stenosis.

Animals↗
PubMed2002

Safety and outcome of endoscopic snare excision of the major duodenal papilla.

BACKGROUND: The optimal management of adenoma of the major duodenal papilla is not established. Options include surgical excision, endoscopic ablative techniques, snare excision, and observation with periodic biopsies. The aims of this retrospective study were to determine the safety and outcome of snare excision of the papilla. METHODS: Twenty-eight snare excisions of the papilla were performed in 26 patients. Sixteen had familial adenomatous polyposis. In 22 procedures, a minisnare was used, and in 6 cases a prototype snare was designed for excision of the papilla. Pancreatic stents were placed as a prophylactic measure at the discretion of the endoscopist (n = 10). RESULTS: Histopathologically, resected tissue included 25 adenomas, 1 inflammatory polyp, 1 invasive malignancy, and 1 normal papilla. Immediate complications were minor bleeding (n = 2), mild pancreatitis (n = 4) and a duodenal perforation (n = 1). The presence (n = 10) or absence (n = 18) of a pancreatic stent did not correlate with subsequent pancreatitis (2 in each group, p = NS). Follow-up was available for 21 patients (median, 9 months; range, 2-32 months). Pancreatic duct stenosis at the papillectomy site resulted in pancreatitis in 2 patients (17%) at, respectively, 4 months and 24 months. Follow-up endoscopy revealed recurrent/residual adenomatous tissue in 2 (10%). CONCLUSIONS: Snare excision of the major duodenal papilla was well tolerated. Most complications were mild except for a small duodenal perforation. Stenosis of the pancreatic duct orifice with pancreatitis may be a late complication.

Adenomatous Polyposis Coli↗
PubMed2002

Study of recurrence after surgical resection of intraductal papillary mucinous neoplasm of the pancreas.

BACKGROUND & AIMS: The aim of this study was to determine recurrence and long-term survival after resection of pancreatic intraductal papillary mucinous neoplasm and to correlate recurrence and survival with histology, extent of resection, and duration of follow-up. METHODS: A single pathologist, without knowledge of previous interpretations of histology or clinical data, retrospectively reviewed and classified 113 resected intraductal papillary mucinous neoplasms as invasive carcinoma (n = 40) or as noninvasive neoplasms (adenoma, borderline, or carcinoma in situ; n = 73). Data on recurrence (locoregional or metastatic), follow-up, and cause of death were obtained from patient records and/or by contacting patients and their physicians. RESULTS: In invasive intraductal papillary mucinous neoplasm, recurrence was similar after partial pancreatectomy (18/27; 67%) and total pancreatectomy (8/13; 62%) and occurred within 3 years of resection in 91%. Among noninvasive neoplasms, 5 of 60 (8%) recurred after partial pancreatectomy (median follow-up, 37 months); none recurred after total pancreatectomy (n = 13; median follow-up, 32 months). Recurrence after resection in noninvasive neoplasms was diagnosed after a median of 40 months (range, 23-75 months); recurrence was noninvasive in 3 and invasive cancer in 2. Five-year survival was better for noninvasive compared with invasive intraductal papillary mucinous neoplasm (84.5% vs. 36%; P < 0.001). CONCLUSIONS: Invasive intraductal papillary mucinous neoplasm recurs frequently even after a complete "curative" resection and portends poor survival. In contrast, noninvasive intraductal papillary mucinous neoplasm recurs infrequently after resection, and survival is excellent regardless of the degree of epithelial dysplasia in the tumor.

Adenocarcinoma, Mucinous↗
PubMed2002

In vivo characterization of colonic thermal injury caused by argon plasma coagulation.

BACKGROUND: Argon plasma coagulation has been rapidly accepted for endoscopic obliteration of vascular lesions and superficial tumors. Depth of injury is thought to be limited through preferential discharge of energy to nondesiccated tissue. However, argon plasma coagulation-induced injury has not been well characterized. The aim of this study was to characterize argon plasma coagulation-induced colonic injury by using a porcine model. METHODS: Laparotomy was performed in 6 female swine and the colon exteriorized with the subjects under general anesthesia. Lesions were made with an argon plasma coagulation probe held perpendicular and 2 mm from the mucosa. Variables studied were as follows: power (45 W, 60 W, and 75 W) and duration (1, 2, or 3 seconds; n = 11 for each power/duration combination). Injury was graded as either superficial or deep, involving the muscularis propria. RESULTS: Circular muscle layer injury correlated closely with power (p = 0.02), duration (p = 0.001), and total energy delivered (r = 0.977). Longitudinal muscle damage was associated with duration of burn (p = 0.001) and total energy delivered (r = 0.855), but correlated poorly with power (p = 0.40). No perforations occurred. Submucosal injection of saline solution had a protective effect with reductions in circular (90% to 10%, p = 0.002) and longitudinal muscle injury (50% to 0%, p = 0.1). CONCLUSIONS: Injury to the muscularis propria occurs at recommended settings for argon plasma coagulation. Injury correlates with power setting, duration of burn, and total energy delivery. Protective arcing to nondesiccated tissue does not appear to be significant in vivo. Submucosal injection of saline solution protects against deep injury.

Animals↗
PubMed2002

Efficacy of colonic submucosal saline solution injection for the reduction of iatrogenic thermal injury.

BACKGROUND: Submucosal saline solution injection may limit the depth of thermal injury to the gut wall by acting as a heat-sink and by increasing the distance between burn and serosa. The aim of this study was to determine the effect of submucosal saline solution injection on depth of colonic thermal injury produced by commonly used endoscopic thermal modalities. METHODS: Longitudinal colotomy incisions were made on the antimesenteric colonic border of anesthetized swine. Lesions were made by using a bipolar device (20 W, 2 seconds), heat probe (30 J); monopolar contact with hot biopsy forceps (20 W, 2 seconds), and monopolar noncontact with argon plasma coagulation (45 W, 3 seconds). Ten or more lesions were created with each device. Lesions were made with or without prior submucosal injection of 2 mL of normal saline solution. After 24 hours the lesions were excised for histologic analysis. Injury was assessed in relation to the severity of damage to the deep (longitudinal) muscle layer. RESULTS: The proportions of control lesions (without submucosal saline solution injection) in which deep injury was evident were as follows: argon plasma coagulation, 86%; hot biopsy forceps, 64%; heat probe, 50%; bipolar device, 18%. Submucosal saline solution injection significantly reduced the proportions of lesions with deep injury for argon plasma coagulation (p = 0.009) and heat probe (p = 0.03), but not hot biopsy forceps or bipolar device (argon plasma coagulation, 86% to 21%; heat probe, 50% to 0%; hot biopsy forceps, 64% to 50%; bipolar device, 18% to 9%). CONCLUSIONS: At equivalent energy outputs, the bipolar device results in less deep injury than the monopolar or heat probe. Submucosal saline solution injection reduced injury to the muscularis propria caused by both heat probe and argon plasma coagulation, but not hot biopsy forceps. Despite submucosal saline solution injection, caution should be exercised when using prolonged monopolar cautery.

Animals↗
PubMed2002

Evaluation of indeterminate bile duct strictures by intraductal US.

BACKGROUND: Cholangiography and tissue sampling (brush cytology, biopsy) are the standard nonsurgical techniques for determining whether a bile duct stricture is benign or malignant. The aim of this study was to determine whether intraductal US is of assistance in distinguishing benign from malignant biliary strictures. METHODS: A retrospective review was undertaken of 30 patients with indeterminate bile duct strictures who underwent ERCP and tissue sampling from September 1999 to November 2000. A 20 MHz over-the-guidewire intraductal US catheter probe was used during ERCP for further examination of the strictures. Final diagnoses of malignant strictures (18 patients) were confirmed histopathologically; confirmation of benign stricture (12 patients) was based on negative tissue sampling plus extended clinical follow-up. RESULTS: Based on retrospective blinded review, the diagnosis by ERCP was correct in 67% of patients, by tissue sampling in 68%, by combined ERCP/tissue sampling in 67%, and by intraductal US in 90% (p = 0.04 vs. ERCP/tissue sampling) of cases. No complication of intraductal US or ERCP was recorded. CONCLUSIONS: Intraductal US is safe and can improve on the ability at ERCP to distinguish benign from malignant biliary strictures.

Adolescent↗