Biomedical subjects

M B Sheridan

Publications and source records attributed to M B Sheridan.

13 recordsLinked to original sources

PubMed2002

Endoscopic retrograde cholangiopancreatography should no longer be used as a diagnostic test: the case in favour.

The requirement for diagnostic endoscopic retrograde cholangiopancreatography has decreased considerably in the past 10 years. Alternative imaging techniques are now available for the diagnosis of bile duct stones, pancreatic and biliary tract malignancy and inflammatory diseases such as sclerosing cholangitis and chronic pancreatitis. The imaging techniques include endoscopic ultrasonography, magnetic resonance cholangiopancreatography and helical computed tomography. There is good evidence that these techniques have an accuracy comparable to endoscopic retrograde cholangiopancreatography in the diagnosis of diseases of the bile and pancreatic ducts. All of these methods are less invasive than endoscopic retrograde cholangiopancreatography and have extremely low or negligible complication rates. The choice of technique used depends on local availability and expertise. In future, endoscopic retrograde cholangiopancreatography will be reserved exclusively for therapeutic applications.

Bile Duct Diseases↗

PubMed2001

Strictures of the sigmoid colon: barium enema evaluation.

PURPOSE: To assess the accuracy of radiologic interpretation, in the absence of clinical information, in the differentiation of benign and malignant sigmoid strictures at barium enema examination. MATERIALS AND METHODS: On two occasions, four independent observers retrospectively assessed examination findings in 78 patients with documented sigmoid strictures (43 benign, 35 malignant). Each stricture was graded by using a five-point scale (definitely malignant to definitely benign). RESULTS: No significant difference existed between the areas under the receiver operating characteristic curves for the two assessments with any observer. Consensus findings indicated agreement among at least three of the four observers in 68 (87%) and 66 (85%) cases at the first and second assessments, respectively. One benign stricture was called malignant at both assessments. When consensus existed, the positive predictive value for malignant strictures was 96% at both assessments (sensitivity, 63% and 66%). Nine malignant strictures were called benign, three at both assessments. When consensus existed, the positive predictive value for benign strictures was 84% and 88% at the first and second assessments, respectively (sensitivity, 88% and 86%, respectively). CONCLUSION: The differentiation between a benign and a malignant sigmoid stricture can be made in most cases at barium enema examination. When a stricture appears malignant, the diagnosis is usually correct, but caution is advised when a stricture appears benign.

Adult↗

PubMed2000

Pancreatitis: computed tomography and magnetic resonance imaging.

The value of CT in management of severe acute pancreatitis is well established. Some, but not all, experimental studies suggest a detrimental effect of intravenous iodinated contrast agents in acute pancreatitis, but although initial clinical data tends to support this, the positive advantages of enhanced CT outweigh the possible risks. Magnetic resonance imaging has been shown to be as effective as CT in demonstrating the presence and extent of pancreatic necrosis and fluid collections, and probably superior in indicating the suitability of such collections for percutaneous drainage. Image-guided intervention remains a key approach in the management of severely ill patients, and the indications, techniques and results of radiological intervention are reviewed herein. Both CT and MRI can be used to diagnose advanced chronic pancreatitis, with the recent addition of MRCP as a viable alternative to diagnostic endoscopic retrograde cholangiopancreatography (ERCP). Both MRCP and CT/MR imaging of the pancreatic parenchyma still have limitations in the recognition of the earliest changes of chronic pancreatitis--for which ERCP and tests of pancreatic function remain more sensitive--but the clinical significance of these minor changes remains contentious.

Acute Disease↗

PubMed2000

A prospective randomised multicentre trial comparing 10 Fr Teflon Tannenbaum stents with 10 Fr polyethylene Cotton-Leung stents in patients with malignant common duct strictures.

BACKGROUND: Stent blockage is a multifactorial process in which stent design and materials, bacteria, proteins, and bile viscosity play a role. AIMS: To compare the patency of the 10 Fr Teflon Tannenbaum (TT) stent to that of the 10 Fr Cotton-Leung (CL) polyethylene stent with sideholes, in patients with malignant obstructive jaundice. METHODS: Patients were recruited to this prospective multicentre randomised study if they had a newly diagnosed malignant bile duct stricture below the hilum of the liver suitable for stenting with a 10 Fr stent. Data were collected and monitored by a professional monitoring company. Primary patency was the interval between stent placement and first exchange or death without recurrent jaundice. RESULTS: 134 consecutive patients were recruited between November 1994 and June 1997; 65 were randomised to the TT stent and 69 to the CL stent. Median patency and 95% confidence intervals were 181 (59, 303) days for the TT stent and 133 (92, 174) days for the CL stent, with no significant difference between the two stents (p=0.49). Median survival and 95% confidence intervals were 115 (71, 159) days for the TT stent and 151 (112, 190) days for the CL stent, with no significant difference between the two stents (p=0.765). CONCLUSION: Neither Teflon as a stent material nor the Tannenbaum design prolong the patency of plastic stents.

Adult↗

PubMed1999

The predictive value of transabdominal ultrasonography in the diagnosis of biliary tract complications after orthotopic liver transplantation.

BACKGROUND: In transplant recipients with choledococholedocostomy (CDCD), endoscopic retrograde cholangiopancreatography (ERCP) remains the gold standard for the diagnosis of biliary leak or strictures. Transabdominal ultrasonography (TAUS) has been used to screen patients with suspected biliary tract complications, prior to ERCP, although the clinical effectiveness remains unclear. AIMS: To assess the predictive value of TAUS in the diagnosis of biliary tract complications after liver transplantation. METHODS: 144 consecutive ERCP and corresponding ultrasonogram reports performed over a 67 month period in 79 patients after liver transplantation were analysed retrospectively. RESULTS: 77 ERCP patients had both a TAUS and a successful ERCP. Biliary tract abnormalities were found at TAUS in 49 (64%) of the 77 patients. TAUS had an overall sensitivity of 77%, and specificity of 67%, with positive and negative predictive values of 26% and 95% respectively, when adjusted for the prevalence rate of biliary complications after liver transplantation of 12.8% in our population. The use of bile duct calibre as sole criterion for an abnormal scan improved the specificity (76%) and with a corresponding reduction in sensitivity (66%). The risk of false negative TAUS was similar in both the early and late post-transplant periods. CONCLUSIONS: A normal TAUS after liver transplantation with CDCD makes the presence of biliary complications unlikely.

Adult↗

PubMed1999

Dynamic contrast-enhanced MR imaging and dual-phase helical CT in the preoperative assessment of suspected pancreatic cancer: a comparative study with receiver operating characteristic analysis.

OBJECTIVE: The purpose of this study was to compare dynamic contrast-enhanced MR imaging and dual-phase helical CT in the preoperative assessment of patients with suspected pancreatic carcinoma. SUBJECTS AND METHODS: Thirty-three consecutive surgical candidates (20 men, 13 women; 39-81 years old) were included. MR imaging comprised fast spin-echo (TR/TE 4000/91), fat-suppressed T1-weighted spin-echo (500/15), and T1-weighted breath-hold gradient-echo fast low-angle shot (100/4; flip angle, 80 degrees) images before and after the administration of gadopentetate dimeglumine. Helical CT used 5-mm collimation with a pitch of 1:1.5-1.7; images were obtained 20 and 65-70 sec after injection of 150 ml of contrast material. Two pairs of interpreters who were unaware of the results of the other imaging method independently scored each examination for the presence of a lesion and for surgical resectability using a five-point scale. Results were correlated with surgery (n = 25) or consensus review (n = 8). Receiver operating characteristic methodology was used to analyze the results for resectability, and positive predictive values were calculated. RESULTS: Both MR imaging and helical CT revealed 29 of 31 lesions. In determining lesion resectability, the mean areas under the receiver operating characteristic curves were 0.96 and 0.81 (p = .01) and the positive predictive values were 86.5% and 76% (p = .02) for MR imaging and helical CT, respectively. CONCLUSION: MR imaging and helical CT performed equally well in lesion detection. MR imaging was significantly better in the assessment of resectability of pancreatic tumors.

Adenocarcinoma↗

PubMed1998

Increased intestinal permeability and altered mucosal immunity in cholestatic jaundice.

OBJECTIVE: To examine the effects of cholestatic jaundice on gut barrier function. SUMMARY BACKGROUND DATA: Gut barrier failure occurs in animal models of jaundice. In humans, the presence of endotoxemia indirectly implicates failure of this host defense, but this has not previously been investigated in jaundiced patients. METHODS: Twenty-seven patients with extrahepatic obstructive jaundice and 27 nonicteric subjects were studied. Intestinal permeability was measured using the lactulose-mannitol test. Small intestinal morphology and the presence of mucosal immunologic activation were examined in endoscopic biopsies of the second part of the duodenum. Systemic antiendotoxin core IgG antibodies and serum interleukin-6 and C-reactive protein were also quantified. Intestinal permeability was remeasured in 9 patients 5 weeks after internal biliary drainage. RESULTS: The median lactulose-mannitol ratio was significantly increased in the jaundiced patients. This was accompanied by upregulation of HLA-DR expression on enterocytes and gut-associated lymphoid tissue, suggesting immune activation. A significant increase in the acute phase response and circulating antiendotoxin core antibodies was also observed in the jaundiced patients. After internal biliary drainage, intestinal permeability returned toward normal levels. CONCLUSIONS: A reversible impairment in gut barrier function occurs in patients with cholestatic jaundice. Increased intestinal permeability is associated with local immune cell and enterocyte activation. In view of the role of gut defenses in the modern paradigm of sepsis, these data may directly identify an important underlying mechanism contributing to the high risk of sepsis in jaundiced patients.

Acute-Phase Reaction↗

PubMed1998

Gut barrier function in malnourished patients.

BACKGROUND: The integrity of the gastrointestinal mucosa is a key element in preventing systemic absorption of enteric toxins and bacteria. In the critically ill, breakdown of gut barrier function may fuel sepsis. Malnourished patients have an increased risk of postoperative sepsis; however, the effects of malnutrition on intestinal barrier function in man are unknown. AIMS: To quantify intestinal barrier function, endotoxin exposure, and the acute phase cytokine response in malnourished patients. PATIENTS: Malnourished and well nourished hospitalised patients. METHODS: Gastrointestinal permeability was measured in malnourished patients and well nourished controls using the lactulose:mannitol test. Endoscopic biopsy specimens were stained and morphological and immunohistochemical features graded. The polymerase chain reaction was used to determine mucosal cytokine expression. The immunoglobulin G antibody response to endotoxin and serum interleukin 6 were measured by enzyme linked immunosorbent assay. RESULTS: There was a significant increase in intestinal permeability in the malnourished patients in association with phenotypic and molecular evidence of activation of lamina propria mononuclear cells and enterocytes, and a heightened acute phase response. CONCLUSIONS: Intestinal barrier function is significantly compromised in malnourished patients, but the clinical significance is unclear.

Aged↗

PubMed1998

Imaging of pancreatic trauma.

This pictorial review discusses the imaging findings in acute pancreatic injury and its delayed complications. These findings are related to key decisions in surgical management. Emphasis is placed on the difficulty of acute diagnosis using CT and the pivotal role of endoscopic retrograde pancreatography (ERP) in the definition of ductal anatomy with delayed diagnosis.

Algorithms↗

PubMed1997

Complications of barium enema examinations: a survey of UK Consultant Radiologists 1992 to 1994.

Questionnaires were sent to all Consultant Radiologists in the UK regarding complications from barium enema examinations. The 756 respondents performed a total of 738,216 examinations over the three year period 1992 to 1994. Seventy-seven Consultants (10.2%) reported a total of 82 complications including 13 deaths: an overall mortality rate of 1 in 56,786. Only three of 30 (10%) cases of bowel perforation died, as compared with nine out of 16 (56%) cases of cardiac arrhythmia. The only remaining death was a consequence of vaginal intubation. Details of all the reported complications are recorded. This was an entirely retrospective study.

Adult↗

PubMed1997

Retention balloon catheters and barium enemas: attitudes, current practice and relative safety in the UK.

Balloon catheters have been associated with increased morbidity and mortality leading some to believe they should be banned, yet others find them both useful and safe if used properly. Questionnaires were sent to all Consultant Radiologists in the UK to document current practice. Particular attention focused on whether eight safety aspects are considered during their use. In this entirely retrospective study complications with both balloon and standard tip catheters were recorded during the 3-year-period 1992 to 1994 to assess their relative safety. Twenty-two percent of UK Radiologists routinely used a rectal balloon. This was not associated with any increase in mortality, but extraperitoneal rectal perforation was increased by a factor of 2.5. The routine use of retention balloon catheters may not be justified.

Attitude of Health Personnel↗

PubMed1996

PEG -- is the E necessary? A comparison of percutaneous and endoscopic gastrostomy.

We describe our experience of 45 percutaneous gastrostomies using 12 F Wills-0glesby (Cook, Inc, Bloomington, IN, USA) catheters and 33 percutaneous endoscopic gastrostomies using 12 F Bower PEG's (Corpak, Inc, Wheeling, IL, USA). Tube displacement was a continued problem with the Wills-Oglesby catheter resulting in three patients developing peritonitis with one death. In view of this we would recommend as the preferred technique the endoscopic placement of Bower PEG catheters unless there are contraindications to the endoscopic technique.

Catheterization↗

PubMed1993

Transabdominal ultrasonography as the primary investigation in patients with suspected Crohn's disease or recurrence: a prospective study.

Traditionally, patients with suspected or known and possible recurrent Crohn's disease have been investigated by small bowel barium radiology, which incurs a relatively high radiation dose. Despite patient selection a significant number have a normal barium examination. A prospective study was performed to evaluate the use of transabdominal ultrasound as the initial investigation in these two groups. One hundred and twenty-seven patients were examined, including 31 with a previous history of Crohn's disease. In the known Crohn's disease group there were 14 true positive ultrasound examinations and eight true negative, with six false positive and three false negative examinations. In the 96 patients not previously known to have Crohn's disease, there were 18 true positive and 70 true negative examinations, with two false positive and six false negative examinations. The overall sensitivity for ultrasound was 78% with a specificity of 91%. A significant learning curve was apparent in the early stages of study; in the last 64 patients the sensitivity was increased to 87%. These data support the use of ultrasound as the initial investigation in patients with suspected Crohn's disease or recurrence, prior to consideration for small bowel barium radiology, to reduce the large number of unnecessary small bowel barium examinations currently being performed.

Adult↗