MRCP in patient care: a prospective survey of gastroenterologists.

OBJECTIVE: MRCP is increasingly used to evaluate pancreaticobiliary disease, yet its effect on patient care is unknown. The purpose of this study was to measure the effect of MRCP on referring physicians' initial diagnoses, the physicians' confidence in their diagnoses, and the influence of MRCP results on clinical management. SUBJECTS AND METHODS: We prospectively surveyed gastroenterologists who referred patients for nonurgent MRCP for pancreaticobiliary evaluation. Before MRCP, gastroenterologists reported the working diagnosis, confidence level (high, moderate, low), and next step in clinical management if MRCP was unavailable. MRCP was performed with standard protocols, including secretin enhancement. After reviewing MRCP findings and without referring to their previous assessment, gastroenterologists reported a revised diagnosis, confidence level, and next step in clinical management. They then compared pre- and post-MRCP management plans and rated the influence of MRCP on changing management from 1 (none) to 5 (major). Diagnostic confidence and frequency of common diagnoses and recommendation for an invasive next-step procedure (e.g., ERCP) or endoscopic ultrasound were compared between pre- and post-MRCP assessments. RESULTS: Survey data were analyzed on 171 patients (123 women, 48 men; mean age, 50 [SD, 17] years; range, 19-88 years) undergoing MRCP for unexplained abdominal pain (42.9%), suspected pancreaticobiliary neoplasm (20%), recent acute (17.1%) or suspected chronic (14.9%) pancreatitis, and other indications (5.1%). Recommendations of ERCP and endoscopic ultrasound decreased after MRCP (from 49.1% to 35.1%, p=0.03, and from 26.9% to 13.5%, p≤0.01). After MRCP, high confidence in diagnosis increased (from 72/171 to 100/171, p<0.01), as did recommendations for noninvasive therapy (from 18/171 to 56/171, p<0.01). A major or substantial change in clinical management was made in the care of 67 of 171 patients (39.2%). CONCLUSION: Use of MRCP significantly changes gastroenterologists' treatment of patients with suspected pancreaticobiliary disease by increasing diagnostic confidence and reducing the frequency of invasive follow-up procedures.

Pancreatic cancer: utility of dynamic contrast-enhanced MR imaging in assessment of antiangiogenic therapy.

PURPOSE: To prospectively evaluate the utility of dynamic contrast material-enhanced magnetic resonance (MR) imaging in predicting the response of locally advanced pancreatic cancer to combined chemotherapy and antiangiogenic therapy. MATERIALS AND METHODS: This prospective, institutional review board-approved, HIPAA-compliant study with informed consent assessed dynamic contrast-enhanced MR imaging in 11 patients (mean age, 54.3 years; six men and five women) with locally invasive pancreatic cancer before and 28 days after combined chemotherapy and antiangiogenic therapy. Axial perfusion images were obtained after injection of 0.1 mmol gadopentetate dimeglumine per kilogram of body weight. Sagittal images of the upper abdominal aorta were obtained for arterial input function calculation. A two-compartment kinetic model was used to calculate the perfusion parameters K(trans) (the rate constant that represents transfer of contrast agent from the arterial blood into the extravascular extracellular space), K(ep) (the rate constant that represents transfer of contrast agent from the extravascular extracellular space to the blood plasma), and volume of distribution (v(e)). Semiquantitative measurements, peak tissue gadolinium concentration (C(peak)), maximum slope of gadolinium increase (slope), and area under the gadolinium curve at 60 seconds (AUC(60)) were also calculated. Perfusion parameters and tumor size changes were correlated with carbohydrate antigen 19-9 levels. Comparisons between pre- and posttreatment studies were performed by using the Wilcoxon signed rank test, and comparisons between responders and nonresponders were performed by using the Mann-Whitney test. RESULTS: After therapy, K(trans), v(e), C(peak), slope, and AUC(60) decreased significantly (P = .02, .001, .002, .007, and .01, respectively). Tumor size and K(ep) were not significantly changed. Pretreatment K(trans) and K(ep) were significantly higher (P = .02 and .006, respectively) in tumors that showed marker response than in those that did not. A pretreatment K(trans) value (milliliters of blood per milliliter of tissue times minutes) of more than 0.78 mL/mL . min was 100% sensitive and 71% specific for subsequent tumor response. Semiquantative parameters and tumor size were not different between the groups. CONCLUSION: Pretreatment K(trans) measurement in pancreatic tumors can predict response to antiangiogenic therapy. All perfusion parameters showed substantial reduction after 28 days of combined chemotherapy and antiangiogenic therapy.

Assessment of chronic pancreatitis: utility of diffusion-weighted MR imaging with secretin enhancement.

PURPOSE: To retrospectively measure and compare changes in pancreatic apparent diffusion coefficient (ADC) following secretin administration in patients with and those without chronic pancreatitis (CP) who underwent magnetic resonance (MR) cholangiopancreatography with diffusion-weighted (DW) imaging. MATERIALS AND METHODS: This retrospective HIPAA-compliant study was approved by the authors' institutional review board, with waiver of informed consent. Eighty-nine patients were categorized by the referring gastroenterologist as having no CP (n = 37), mild CP (n = 33), or severe CP (n = 19) on the basis of Cambridge criteria and/or clinical course. Mean age was 52.2 years (range, 21-82 years) in women and 54.3 years (range, 32-81 years) in men. Patients underwent 1.5-T MR cholangiopancreatography, including DW sequences (b = 0, 100, and 400 sec/mm(2)) performed serially for 10 minutes after secretin injection. Severity level of CP was analyzed for sex (Fisher exact test) and age (analysis of variance) differences. Pairwise comparisons of mean ADCs for each parameter (no CP vs mild CP, no CP vs severe CP, mild CP vs severe CP) were performed (Mann-Whitney test). Threshold values of non-secretin-enhanced ADC for pancreatitis discrimination were calculated with receiver operating characteristic analysis. P < .05 was considered to show a significant difference. RESULTS: Patients with severe CP were more likely to be men than were those without pancreatitis; there were no significant age differences between groups. Mean nonenhanced and maximum secretin-enhanced ADCs were higher in patients without CP than in those with mild or severe CP but did not vary between those with mild and severe CP. Percentage increase in ADC after secretin injection and time to peak ADC did not vary among groups. An ADC of less than 179 x 10(-5) mm(2)/sec was optimal for delineating normal pancreas from CP groups. CONCLUSION: In symptomatic patients, baseline pancreatic ADC obtained with DW imaging prior to secretin administration may aid in diagnosis of CP and assessment of its severity; ADC response to secretin administration may be less useful.

Diagnosis of chronic pancreatitis by using apparent diffusion coefficient measurements at 3.0-T MR following secretin stimulation.

PURPOSE: To prospectively measure pancreatic apparent diffusion coefficient (ADC) before and after secretin administration in subjects with and without chronic pancreatitis (CP) who underwent magnetic resonance (MR) cholangiopancreatography with diffusion-weighted (DW) imaging at 3.0 T. MATERIALS AND METHODS: Institutional review board approval of this HIPAA-compliant study was obtained. Healthy volunteers, and patients with suspected and/or known CP who were scheduled for MR cholangiopancreatography, were recruited and gave written informed consent. All subjects underwent 3.0-T MR cholangiopancreatography, including serial DW imaging sequences (b = 0, 200, and 400 sec/mm(2)) acquired for 15 minutes after secretin administration. The referring gastroenterologist then classified subjects as healthy or with mild or severe CP, given endoscopic retrograde cholangiopancreatographic and/or clinical findings. CP severity was analyzed for sex and age. Mean presecretin and maximum postsecretin ADCs were compared between groups. Pairwise mean ADCs for healthy versus mild CP patient groups, healthy versus severe CP patient groups, and mild versus severe CP patient groups were compared. Presecretin ADC threshold levels for CP discrimination were calculated (P < .05). RESULTS: Thirty-two subjects were imaged; four CP patients were excluded owing to severe artifact, and the remaining 28 (15 healthy patients, five with mild CP, and eight with severe CP) comprised the study population. All CP patients had endoscopic retrograde cholangiopancreatographic confirmation of CP. Mild or severe CP patients were older than healthy patients; sex distribution did not vary among groups. Mean presecretin and maximum postsecretin ADCs were higher in healthy patients than in either mild or severe CP groups (P < .01), but did not vary between mild and severe CP groups (P = .25-0.28). An ADC of less than 220 x 10(-5) mm(2)/sec was optimal for delineating between healthy and CP patients. CONCLUSION: Pancreatic ADC obtained with DW imaging at 3.0 T prior to secretin administration may help diagnose CP; postsecretin ADC response does not distinguish CP severity.

Dynamic secretin-enhanced MR cholangiopancreatography.

Secretin causes temporary dilatation of pancreatic ducts, principally by increasing pancreatic exocrine secretions, and thus allows better visualization of the ducts at magnetic resonance (MR) cholangiopancreatography. Secretin-enhanced MR cholangiopancreatography is useful for detection and diagnosis of a variety of congenital, inflammatory, and neoplastic conditions of the pancreas. Although MR cholangiopancreatography without secretin is a reliable method for evaluating the pancreatobiliary ductal system, the authors believe that secretin-enhanced MR cholangiopancreatography gives additional valuable functional and anatomic information about the pancreatic duct and pancreatic excretory capacity.

MR cholangiopancreatography in children: feasibility, safety, and initial experience.

BACKGROUND: The indications for MR cholangiopancreatography (MRCP) in children, and its safety and findings, might differ from those in adults and are not well described. OBJECTIVE: To investigate the safety, feasibility, and accuracy of MRCP in children. MATERIALS AND METHODS: We reviewed all prospective MRCP reports, noting the indication, the use of secretin, endoscopic retrograde cholangiopancreatography (ERCP) findings, and patient outcomes. Two readers reviewed each MRCP study by consensus to rate duct visualization and compare pancreatic duct sizes before and after secretin administration (paired t-test). The likelihood of a normal versus an abnormal MRCP study was compared by gender, pancreatitis as the primary indication, secretin use, and whether ERCP was performed (Fisher's exact test), as well as age (t-test). RESULTS: A total of 85 MRCP studies were performed in children (mean age 10.3 years), most commonly for evaluation of pancreatitis (n=47, 55%); 41 (48%) used secretin and 39 (46%) used a negative oral contrast agent. Of the 85 studies, 72 (85%) had excellent image quality and 43 were normal. ERCP was performed after 16 of the 85 MRCP studies (19%); the diagnoses were concordant with those of MRCP in 13 (81%). There were 42 abnormal MRCP studies, and these were more likely to be in girls (P=0.03) and in children who had undergone ERCP (P<0.01). Secretin and the negative oral contrast agent were well-tolerated. Secretin improved duct visualization (P<0.001). CONCLUSION: MRCP safely and accurately depicted pancreaticobiliary anatomy in children. The use of secretin improved visualization of the pancreatic duct.