The Value Of Magnetic Resonace Cholangiopancreatography In Diagnosing Malignant And Inflammatory Biliary Obstructive Diseases

Objective:To explore the clinic value of magnetic resonace cholangiopancreato-graphy (MRCP) in diagnosing malignant and inflammatory biliary obstructive diseases.Materials and Method: 46 patients were chosen in the study including 27 malignant tumor patients and 19 cholangitic stenosis patients. Among them 6 primary hepatocellular carcinoma, 6 bile duct carcinoma, 6 ampullary carcinoma, 7 carcinoma of pancreatic head, 2 metastasis carcinoma involved in malignant tumor patients and 7 dodecadactylon sclerosing papillitis, 3 sclerosing cholangitis, 1 acute suppurative cholangitis, 1 acute cholangitis involved in cholangitic stenosis patients. All the patients were examined by MRCP and 33 patients received B-mode ultrasonography, 2 received endoscopic ultrasonograpy, 14 received CT(Computer tomography) examination, 14 received ERCP (Endoscopic retrograde cholangiopancreatography) which included 2 unsuccessful cases, 2 received PTC(Percutaneous transhepatic cholangiography), 2 received PET(Positron emission tomography) and 18 received operation. The study was conducted on Siemens 1.5T Vision Plus magnetic resonance imaging scaning apparatus. The patients were inhibited from food and water for 4 hours and took contrast medium orally 20 minutes before the examination. Phased-array body coil was used in the examination, and data were collected bytaking single slice and multi-slice scaning at heavily T2 weighted imaging in TSE and HASTE sequence respectively with respiration helding and fat suppression, three dimensional reconstruction of the multi-slice original image was done, then analyzed the screenage and diagnostic results and compared with ERCP or PTC. All the diagnosis was based on pathology, operation or strict clinical examination.Results: Among 27 cases of malignant obstruction, there were 13 located in porta hepatis (including 6 primary hepatocellular carcinoma, 6 bile duct carcinoma and 1 metastasis carcinoma), 9 located in head of pancreas (including 1 ampullary carcinoma, 7 pancreatic head carcinoma and 1 metastasis carcinoma), and 5 located in papilla of duodenum area (all of them were ampullary carcinoma). The bile duct obstructive form showed abruptly cut-off in 18 cases (67%), then in turn beak shape in 5 cases (19%), round-blunt in 2 cases (7%) and irregular centripetal constriction in2 cases (7%). Dilation in slight degree included 1 case (4%), middle degree included 5 (19%) and serious degree included 21 cases (78%). Intrahepatic duct dilation appeared like soft vine in 26 cases (took percentage of 96) and only 1 case like withered branches (took percentage of 4). In addition dual pipes sign could be seen in3 cases of ampullary carcinoma, 5 carcinoma of head of pancreas, 1 metastasis carcinoma from pancreatic head and 1 primary hepatocellular carcinoma which mergered with lymph node metastasis of papilla of duodenum. The dual pipe sign meaned bile duct and pancreatic duct which located above obstructive part dilating together. Dilated bile duct separated from pancreatic duct in dual pipe sign of pancreatic head carcinoma, however low part of bile duct in ampullary carcinoma was constricted and obstructive which paralleled with dilated pancreatic duct approaching duodenal ampulla. Disease of porta hepatis manifested intrahepatic bile duct and common hepatic duct dilating obviously in 10 cases, however choledocho dilated unmarked and bile duct of porta hepatis didn't have any significant display. Intrahepatic bile duct and extrahepatic bile duct dilated obviously in 15 cases with disease locating in pancreatic head, papilla of duodenumln and low part of choledocho. It could show existence of tumor obviously with the help of MRCP original imaging and routine MRI screenage. The tumor located in outside of bile duct in 20 cases, 5 inside, 1 in both outside and inside and 1 growing around the bileduct. Low part of choledocho was compressed upward displacement in 2 pancreatic head carcinoma which made choledocho winding and folding looking like an "S".Among 19 cases of inflamed obstruction, 6 located in head of pancreas, 11 in papilla of duodenum, and 2 cases had a wide constrictive area involving middle and low part of choledocho, which manifested a steady gradual constriction. 12 cases showed centripetal constriction (63%) in the obstructive form, 4 coming next showed round-blunt(21%), 2 showed abruptly cut-off (11%) and 1 beak shape (5%). Bile duct dilation included 2 slight degree cases (11%). 15 middle degree cases (79%) and 2 serious degree cases(ll%). Intrahepatic bile duct dilation appeared like withered branches in 15 cases (79%) and soft vine in 4 cases(21%). In addition 2 cases had slight pancreatic duct dilation, 1 case had obvious cystic duct dilation, the dilation degree of extrahepatic bile duct was more obvious than intrahepatic bile duct in 16 cases, and 2 cases were contrary, extrahepatic bile duct and intrahepatic bile duct dilated widely at the same degree in 1 case. There was no obvious space occupying disease in 19 inflamed constriction and no manifestation of compressed deformation and displacement in bile duct.27 cases of malignant obstruction were diagnosed by MRCP in this group, which included 26 final diagnosis and 1 misdiagnosis. 19 cases of inflamed obstruction included 18 final diagnosis and 1 misdiagnosis. If connected with routine MRI broken slice image the final diagnosis rate of MRCP is 96% which is similar with ERCP or PTC (88%). In addition the quality of single slice scaning image is better than multi-slice.Conclusion: l.MRCP can display normal dissection form of pancreatic duct and bile duct system, various kinds of dissociation of bile duct and pancreas divisum, when used in obstructive diseases of bile duct it can make obstructed locus, coverage and abnormal pancreatic character clear, which makes it have great value in clinical diagnosis.2.The main MRCP manifestation of malignant obstructive bile duct is: Obstructive locus depends on the tumor locus, the obstructive form mostly appears like abruptly cut-off, sometimes like beak, round-blunt and irregular centripetal. The bile duct above obstruction dilates obviously, mostly in the middle and serious degree and very few in the light degree. Intrahepatic bile duct dilates obviously like soft vinemostly and minority like withered branches if chronic inflammation exists at the same time. Malignant obstruction which locates in pancreatic head, duodenal ampulla and papilla of duodenum can cause pancreatic duct dilate at different levels, when the bile duct above obstructive area dilates obviously, therefore characteristic dual pipe sign appears. The bile duct near to tumor can demonstrate compressive displacement and deformation. In addition, the malignant disease of hepatic porta can lead to extreme intrahepatic bile duct dilating, but the bile duct below the disease dilates unmarked, the developing is normal and there is not visualization in porta hepatis which can be regarded as an important symbol in the diagnosis of malignat disease of hepatic porta. The existence, form, coverage and adjacent relation with tissue nearby can be shown clearly in multi-slice original image and routine MRI image, which can be intensified if strengthing the tumour scan, and have important significance to the disease localization and qualitative diagnosis.3.The main manifestation of obstructive inflamed bile duct in MRCP: Constriction mostly locates in low part of choledocho, pancreatic head and papilla of duodenum, and bile duct usually demonstrates gradual centripetal constriction, softer wall, longer constricted segment and unmarked breaks which manifests infarcted partly. The above bile duct constriction dilates in middle or slight degree mostly and very few in serious degree. The intrahepatic bile duct dilates lesser than extrahepatic bile duct and the majority appears like withered branches. Edema and "congestions are obvious in the wall of bile duct when it is in acute inflammation which can lead to local constriction and infart rapidly in very short time and some of them appear like soft vine sign. Inflamed obstructive disease usually can't cause pancreatic duct dilate at the same time, namely without the characteristic manifestation of dual pipe sign belonging to malignant disease. Very a few can cause pancreatic duct dilate slightly when pancreatitis mergers. There is not any accurate space occupying disease in inflamed obstruction and no compressive deformation and displacement in bile duct.3 MRCP can show the obstructive form of bile duct, the severity of bile duct dilation, the dilated form of intrahepatic bile duct, dual pipe sign and whether there is space occupying disease of bile duct, which is very important to distinguish malignant obstruction from inflamed obstruction.4.MRCP has the following virtue comparing with ERCP or PTC: (1) It is safe, non-invasive, examining time short and complication will not happen; (2) It can show actual caliber condition of bile duct; (3) It has the virtue of cross section imaging and contrast examination at the same time; (4) It can provide more diagnostic information than ERCP and PTC connecting with MRI; (5) The efficience is higher than ERCP and PTC. MRCP also has the following defect comparing with ERCP or PTC: (1) Spatial resolution is limited; (2) It can't show physiological active condition of bile duct dynamically; (3) It is hard to display internal structure and signal character of tumor; (4) The image quality is influenced by gastrointestinal vermiculation, fluid in gastrointestinal tract and other confusion agent; (5) It doesn't have the function of treatment. So comprehensive evaluation connecting with MRI should be done in the diagnostic course...