The Preliminary Observations Of The Blood Supplying Arterioles Of Extrahepatic Bile Duct By Sub Millimeter CT

Background:The advances of medical technology shed light on the surgical development of minimal invasion, small incision and small field of view. Simultaneously, biliary surgery keeps pace with the developed instruments as well as the improved approaches. All these, however, contribute little to certain complications such as intraoperative biliary ischemia and hemorrhagic lesions. These problematic issues arise from preoperative unpredictability in biliary blood supply and fine pipeline anatomically on one hand and from the surgeon’s unfamiliarity with anatomy of operated regions, arbitrary dissection and ligation of ducts and excessive pursuit of small field of view. The previous studies have enlightened us by abundant research in blood supply of extrahepatic biliary tract from cadaver specimens and experimental animals, but seldom probed into in vivo human biliary blood supply.In recent years, the technology of medical imaging has propelled the swift development of CT, which contributes especially to sub-millimeter CT angiography as an approach to in vivo human vascular anatomy. At present, CT angiography has progressed up to digital subtraction angiography in respect of arterial imaging effect. Technically, the former surpasses the latter for its advantage in complete indications of spatial constructions anatomically. Moreover, CT angiography is also superior to MR imaging in spatial resolution for epigastrial vascular imaging.Objective:This research aims to study the origin and distribution of blood-supplying arterioles of extrahepatic bile duct using submillimeter CT so as to explore the value of CT angiography in planning individualized scheme for biliary surgeries and provide a basic ground for the biliary simulation surgeries.Methods:1. The sub-millimeter imaging data of the patients undergoing upper abdominal CT angiography from Zhujiang Hospital, Southern Medical University during September30and January1,2011. Inclusion criteria:extrahepatic bile duct and its anatomically-intact adjacent tissues; sharp fat gaps surrounding extrahepatic bile duct and extrahepatic bile duct clearly distinguished by sub-millimeter CT images; blood supply arteries of extrahepatic bile duct by submillimeter CT imaging without significant respiratory artifact. Exclusion criteria:those with operations on pancreatic duodenal; those with undistinguished extrahepatic bile duct and its adjacent tissue; those with much slender blood supply arteries for extrahepatic bile duct; those receiving repeated imaging except the best image.2.101patients were included:54male,47female; aged5-81year old, averaged51.23years.35patients diagnosed clinically with cholelithiasis (gallstones including common bile duct stones and stones in intrahepatic bile duct),11of them with bile duct and space occupying pancreatic cancer and41with benign and malignant mass in liver, pancreatic body and tail including2cases of the extrahepatic bile duct mass combined with common bile duct calculi,1case of hepatic space-occupying lesions associated with bile duct calculi in1cases and17cases unrelated to hepatobiliary pancreatic diseases.3. Equipment:Philips (Holland) Brilliance64layer spiral CT, Medrad double tube high pressure syringe, CT with a Mxview workstation and the contrast agent of Ultravist (370mgl/mL).4. Examing methods:Gastrointestinal preparation for conventional phase III epigastrial scanning was performed. Scanning time using CT scanning with contrast agent automatic tracking was determined, monitoring spots established at the abdominal aorta of the celiac trunk level, the monitoring scan was started and the scanning began when the monitored value reached200HU after8s delay. The scanning range was set from the diaphragmatic dome to inferior pole of kidneys, using bandage compression or asking the patients to hold breaths. Contrast agent at a dosage of80-100mL was injected using intravenous bolus injection with high pressure injector via antecubital vein at a rate of5mL/s,40-50mL saline was injected at the same rate flush pipe for tube washing. The scanning parameters:tube voltage of120kV, tube current of200mAs, detector layer of64x0.625mm, a pitch of0.891, bed velocity of47.5mm/s, reconstruction rotation time of0.5s, thickness of0.5mm, reconstruction interval of0.5mm.5. Images processing:At completion of scanning, the original arterial phase images of transverse surface were reconstructed into transverse axial images at a layer thickness and a layer interval of0.625mm, with images from plain scanning, parenchymal phase, and lag period constructed in conventional layer thickness and interval. When all images were uploaded onto the work station, the images at arterial phase were investigated, others at other phases used for auxiliary identification of adjacent tissues anatomically. The window width of the arterial phase images were adjusted for tracking observation of consecutive thin layer source images, multiplanar reconstruction, maximum intensity projection imaging and volume rendering so that eventually the CT angiographic images were achieved. In the following, the extrahepatic bile duct and its blood supply arterioles were detected to track the source of the arterioles and their trends, which were further verified and judged using multiplanar reconstruction, maximum intensity projection and volume rendering. 6. Outcome measures:Two experienced physicians in imaging diagnosis were invited to make blind film readings to judge the source, number and distributions of blood supply arterioles of extrahepatic bile duct using a continuous thin layer source image tracking and multiplanar reconstruction, maximum intensity projection imaging and volume rendering. The extrahepatic bile duct was roughly divided into upper and lower segments, the former beginning from the common bile duct to the superior border of duodenum, the latter including posterior segment of duodenum and portions of the pancreas but not pancreas. The segment from common bile duct to posterior pancreas and duodenum was excluded from the study for its shortage in length, abundance and complexity in arterioles. The largest diameter of extrahepatic bile duct was measured.Results:1. All the imageological data from the101patients were employed for analysis. All the image indicated only one common bile duct in each case1, included the upper segment including the partial common bile duct up beginning from superior duodenum and part of common hepatic duct, and the lower one including the partial common bile duct down beginning from posterior duodenum of common bile duct to the part of common bile duct right entering pancreatic parenchyma.2cases of right hepatic artery arose from the gastroduodenal artery and10cases of right hepatic artery/hepatic artery from the superior mesenteric artery.2. The superior pancreaticoduodenal artery in the images from97patients (97%) was observed, running into1-3branches (1in most cases, accounting for85%) in steady direction of starting at the gastroduodenal artery, traveling along anterior common bile duct around to inferior right common bile duct, mostly accompanying the inferior common bile duct. The anastomosis of the superior duodenal arteries with the inferior ones formed arches of aorta, mostly accompanying inferior common bile duct. The artery of right liver in1case had an abnormal direction, accompanying the common bile duct, branching into superior pancreaticoduodenal artery and jointly supplying the inferior artery of common bile duct. No obvious blood supply arteries were found in3cases. The blood supply arterioles in anterior common bile duct in23cases arose from around cystic artery, those in19cases from right hepatic artery, those in2cases from proper hepatic artery, those in1case from common hepatic artery, those in1case from left hepatic artery, and those in3cases from gastroduodenal artery. All these arterioles together with their branches traveled with circuity and no regularity, and most of them just had one branch. For all the23cases, the cystic artery in22cases originated from right hepatic artery and that of only one case from gastroduodenal artery. No blood supply arterioles were visible in more than half of them.3. The images from all the101cases presented blood supply arterioles of extrahepatic bile duct using continuous submillimeter image source tracing, multiplanar reconstruction and maximum intensity projection imaging. Although volume rendering imaging reconstructed rough anterior pancreaticoduodenal artery or cystic artery from the images of only9cases, it was advantageous for the reconstruction of great epigastrical vessels for its direct-viewing and speediness:a primary image of the vessel could be reconstructed in3-5s. The inside diameter of common bile duct was measured to be4-44(11.0±6.9) mm, with a majority of5-12mm.Conclusion:Imaging by sub-millimeter CT may present extrahepatic bile duct and its blood supply arterioles for old patients with cholelithiasis and malignant or benign space-occupying lesions in liver and pancreas, especially for those indicated of biliary surgery, which may enlighten the surgeons with accurate references in anatomy. This study, therefore, discovers the necessity of conducting upper abdominal CT angiography for this group of elderly patients.