A comparative study of magnetic resonance cholangiography and direct cholangiography.

OBJECTIVE: Magnetic resonance cholangiopancreatography (MRCP) is a rapidly developing method for the noninvasive assessment of the biliary tree and pancreatic duct that obviates the need for contrast medium. We describe our experience with this new diagnostic imaging method in patients with obstruction of the biliary tree. We assessed both the location and cause of obstruction, and compared the results with direct cholangiography. METHODS: Between 1997 and 1998, 81 patients underwent MRCP at our facility. Two different image acquisition protocols (half-Fourier acquisition single-shot turbo spin-echo -HASTE- and rapid acquisition with relaxation enhancement -RARE-) for T2-weighted turbo spin echo sequences as well as cross-sectional fast multiplanar gradient-echo pulse (T1-weighted FL2D) and T2-weighted fast spin echo (T2 TSE) sequences were used. All patients underwent direct (either percutaneous or endoscopic retrograde) cholangiography or surgery for confirmation and/or treatment. The images obtained with MRCP were evaluated by two radiologists with expertise in biliary tree imaging who were unaware of the patient's clinical characteristics, and their diagnostic interpretations were compared with the findings obtained upon surgery or direct cholangiography. RESULTS: The sensitivity and specificity of MRCP in ruling out pathologies and detecting the presence of dilatation of the biliary tree were 100%. In assessing the level of the obstruction, sensitivity and specificity varied with location (intrahepatic/hilar, suprapancreatic, intrapancreatic or ampullary). Sensitivity in these locations was 100, 92, 69 and 86%, respectively, whereas specificity was 100, 94, 92 and 91%, respectively. In determining the cause of the obstruction, the results were variable depending on the cause: choledocholithiasis (sensitivity, 89%; specificity, 90%) malignant obstruction (sensitivity, 92%; specificity, 88%), benign stricture (sensitivity, 63%; specificity, 90%), and chronic pancreatitis (sensitivity, 50%; specificity, 99%). CONCLUSIONS: MRCP offered high diagnostic accuracy in the assessment of the occurrence and location of biliary obstruction. Sensitivity and specificity in establishing the cause varied, and were highest for choledocholithiasis and malignant obstruction. MRCP may be used instead of ERCP, which may then be reserved for patients who are likely to require surgery.

[Self-training in needle-knife sphincterotomy]. / Aprendizaje no tutelado de la esfinterotomía de aguja.

AIM: To analyze our experience in self-training in needle-knife sphincterotomy and to estimate the number of procedures necessary to reach competence in this technique. METHOD: Retrospective analysis of the first 60 needle-knife sphincterotomies performed, paying attention to success rates, the need for one or two attempts and the incidence and severity of early complications. The results were analyzed and divided into 2-year periods. The training period was subsequently determined using a qualitative method which combines the three above-mentioned criteria and sets competence level at 90%. RESULTS: Of the 60 attempted needle-knife sphincterotomies (five in Billroth-II patients), 54 (90%) were completed. The procedure was required in 20% of all the sphincterotomies completed. Needle-knife sphincterotomy was completed at the first attempt in 39 (65%) patients and complications appeared in 13 (22%), three (5%) of which were serious but not fatal. Analysis of 2 year periods showed an almost 100% increase in the total number of needle-knife sphincterotomies completed and in those completed at the first attempt, as well as a reduction in the complication rate, which subsequently stabilized at below 15%. Forty needle-knife sphincterotomies were needed to reach competence level. CONCLUSION: Needle-knife sphincterotomy can be learned without training from an endoscopist with experience in this technique. Competence can be reached after 40 procedures. Nevertheless, we propose an alternative method to our own to achieve competence in less time and with fewer complications.