Three-dimensional reconstruction of the biliary tract using spiral computed tomography

Advances in the investigation of obstructive jaundice

The causes of obstructive jaundice are varied, and timely, accurate methods of investigation are essential to avoid the development of complications. Imaging, invasive or non-invasive, should be carefully selected depending on the suspected underlying pathology in order to determine the degree and level of obstruction along with tissue acquisition and staging where relevant. Several imaging techniques will also allow subsequent therapeutic interventions to be carried out. This article reviews advances in the investigation of obstructive jaundice, highlighting recent developments, many of which at present remain restricted to large centres of expertise, but are likely to become more widespread in use as research progresses and local experience continues to improve.

On the mechanical behavior of the human biliary system

This paper reviews the progress made in understanding the mechanical behaviour of the biliary system. Gallstones and diseases of the biliary tract affect more than 10% of the adult population. The complications of gallstones, i.e. acute pancreatitis and obstructive jandice, can be lethal, and patients with acalculous gallbladder pain often pose diagnostic difficulties and undergo repeated ultrasound scans and oral cholecystograms. Moreover, surgery to remove the gallbladder in these patients, in an attempt to relieve the symptoms, gives variable results. Extensive research has been carried out to understand the physiological and pathological functions of the biliary system, but the mechanism of the pathogenesis of gallstones and pain production still remain poorly understood. It is believed that the mechanical factors play an essential role in the mechanisms of the gallstone formation and biliary diseases. However, despite the extensive literature in clinical studies, only limited work has been carried out to study the biliary system from the mechanical point of view. In this paper, we discuss the state of art knowledge of the fluid dynamics of bile flow in the biliary tract, the solid mechanics of the gallbladder and bile ducts, recent mathematical and numerical modelling of the system, and finally the future challenges in the area.

Preoperative diagnosis and efficacy of laparoscopic procedures in the treatment of Mirizzi syndrome

BACKGROUND

The role of laparoscopic procedures in the treatment of Mirizzi syndrome (MS) is not well-defined and remains controversial. We evaluated the preoperative diagnosis and efficacy of laparoscopic procedures in treatment of MS.

STUDY DESIGN

Preoperative diagnosis and cholecystectomy were attempted on 2,012 consecutive patients at a single center and 24 (1.2%) were finally diagnosed with MS. Patients without preoperative endoscopic retrograde cholangiography underwent preoperative spiral CT after IV infusion cholangiography (IVC-SCT).

RESULTS

Fourteen patients had McSherry type I MS (MS I) and 10 had type II MS (MS II). Open operation was performed on patients with MS II or a preoperative suspicion of gallbladder cancer. Laparoscopic cholecystectomy (LC) was performed successfully on 10 of 14 patients with MS I and the remaining 4 patients with MS I were converted to open procedure. At preoperative endoscopic retrograde cholangiography (n = 3) or IVC-SCT (n = 11) on patients with MS I, 3 of 4 (75%) patients who were converted to open operation had a nonvisualized cystic duct, and 9 of 10 (90%) patients with LC had a visualized cystic duct.

CONCLUSIONS

MS I with a visualized cystic duct can be considered to be an indication for laparoscopic operation. IVC-SCT can be a useful tool for correct preoperative diagnosis and assessment of the feasibility of LC in patients with MS I.

Laparoscopic Cholecystectomy in Patients Aged 80 Years and Over

INTRODUCTION

The aging population has led to a significant rise in the number of patients undergoing operations such as cholecystectomy. We have evaluated and compared the results of laparoscopic cholecystectomy (LC) in patients aged 80 years and over with those of patients aged between 65 and 79 years.

METHODS

A total of 471 patients aged 65 to 79 years (group 1) and 45 patients aged>or=80 years (group 2) underwent LC. All patients underwent preoperative spiral computed tomography after intravenous infusion cholangiography and intraoperative cholangiography.

RESULTS

There was a higher incidence of choledocholithiasis and gallbladder cancer in the patients>or=80 years of age. In addition, group 2 patients had a higher incidence of cardiopulmonary disease and higher American Association of Anesthesiology scores than did those in group 1. With respect to the conversion rate to open surgery, morbidity, mortality, and length of hospital stay, there were no significant differences between the two groups. There was a significantly higher incidence of positive bile cultures and gram-negative rods in group 2 patients than in those in group 1.

CONCLUSIONS

Octogenarians tolerated LC well. Therefore, early elective LC should be encouraged to minimize morbidity and mortality in these elderly patients who have symptomatic cholelithiasis.

Nonoperative imaging techniques in suspected biliary tract obstruction

Evaluation of suspected biliary tract obstruction is a common clinical problem. Clinical data such as history, physical examination, and laboratory tests can accurately identify up to 90% of patients whose jaundice is caused by extrahepatic obstruction. However, complete assessment of extrahepatic obstruction often requires the use of various imaging modalities to confirm the presence, level, and cause of obstruction, and to aid in treatment plan. In the present summary, the literature on competing technologies including endoscopic retrograde cholangiopancreatography (ERCP), percutaneous transhepatic cholangiopancreatography (PTC), endoscopic ultrasound (EUS), intraductal ultrasonography (IDUS), magnetic resonance cholangiopancreatography (MRCP), helical CT (hCT) and helical CT cholangiography (hCTC) with regards to diagnostic performance characteristics, technical success, safety, and cost-effectiveness is reviewed. Patients with obstructive jaundice secondary to choledocholithiasis or pancreaticobiliary malignancies are the primary focus of this review. Algorithms for the management of suspected obstructive jaundice are put forward based on current evidence. Published data suggest an increasing role for EUS and other noninvasive imaging techniques such as MRCP, and hCT following an initial transabdominal ultrasound in the assessment of patients with suspected biliary obstruction to select candidates for surgery or therapeutic ERCP. The management of patients with a suspected pancreaticobiliary condition ultimately is dependent on local expertise, availability, cost, and the multidisciplinary collaboration between radiologists, surgeons, and gastroenterologists.

Heterogeneity of subvesical ducts or the ducts of Luschka: a study using drip-infusion cholangiography-computed tomography in patients and cadaver specimens

The objective of this study was to examine the heterogeneity of the subvesical duct or the ducts of Luschka as well as the reliability of drip-infusion cholangiography with computed tomography (DIC-CT) for their identification. DIC-CT was used in 277 consecutive patients (135 men, 142 women) and for the dissection and histologic study of 10 cadaver livers. We found 32 subvesical ducts in 28 (10.1%) of 277 patients. Irrespective of whether the terminals were extra- or intraparenchymal, the subvesical ducts often (17/32 ducts, 15/28 patients) drained into a subsegmental duct of S5 or S4. Notably, some displayed an "intermediate" course along the gallbladder fossa with an intraparenchymal origin and terminated at S5. Such ducts tended to be seen in the elderly. Another 15 ducts drained into a thick, centrally located duct, such as the right sectorial or hepatic duct. The anatomic study demonstrated that the subvesical duct likely included the cystic vein-concomitant duct. A major type of subvesical duct, characterized by an intermediate course along its bed, appeared to result from degenerative exposure of a peripheral duct with aging. The subvesical duct draining into the thick duct included both a "daughter branch," such as seen in the lung, and the so-called anomaly. Such ducts can be demonstrated with DIC-CT, but the incidence might be limited. However, the cystic vein/concomitant duct was difficult to identify radiologically. Consequently, although presurgical radiology is useful for avoiding bile leakage after laparoscopic cholecystectomy, surgeons should be aware of its limitations.

Accuracy of computed tomographic intravenous cholangiography (CT-IVC) with iotroxate in the detection of choledocholithiasis

To determine the accuracy of computed tomographic intravenous cholangiography (CT-IVC) for detection of choledocholithiasis. Sixty-five patients undergoing endoscopic retrograde cholangiography (ERC) underwent CT-IVC prior to ERC, using a single detector helical CT following intravenous infusion of 100 ml iotroxate. Patients with bilirubin levels >3 times normal were excluded. ERC was indeterminate in three patients (4.7%) and CT-IVC in four (6.3%). Twenty-three patients had ductal calculi at ERC, and CT-IVC was positive in 22, with two false positives and one false negative: sensitivity 95.6%, specificity 94.3%. Stones were multiple in nine and solitary in 14. Of the 14 solitary stones, ten were <or=5 mm and eight were <or=4 mm. The bilirubin level in positive cases was within normal in 20. Maximum intensity projection (MIP) reformats showed stones in only 27% of cases and surface rendered (SR) reformats in none. CT-IVC is highly accurate for detection of ductal calculi, including single small calculi, with a normal or near normal serum bilirubin. Axial images should be used for interpretation rather than MIP or SR reformats.

Three-dimensional reconstruction of biliary tract using spiral computed tomography for laparoscopic cholecystectomy

To increase the safety of laparoscopic cholecystectomy, we have analyzed the biliary tract in a three-dimensional fashion. The union of the biliary ducts was studied in 50 patients using spiral computed tomography (CT) after intravenous infusion cholangiography. Depending on the union and course of the cystic duct to the common bile duct, cystic duct anatomy was classified into six categories: ipsilateral gallbladder side (type I) and contralateral side with anterior course (type II); contralateral side with posterior course (type III); intrahepatic side (type IV); intrapancreatic side (type V); and unclassified (type VI). The length of the cystic duct was also determined. The cystic duct was identified in 42 cases (84%); 30 cases (60%) were type I, 9 cases (18%) type III, and a single case (2%) of types II, IV and V, respectively. The length of the cystic duct was < or =2 cm in 30 cases that had a shorter operating time compared to 12 cases with a cystic duct <2 cm (p <0.01). In conclusion, three-dimensional reconstruction of the cystic duct anatomy using spiral CT provides simple classification of bile duct anatomy, and this preoperative information may increase the safety of laparoscopic cholecystectomy.

Impact of multidetector CT on donor selection and surgical planning before living adult right lobe liver transplantation

OBJECTIVE

This study was performed to document the impact of multidetector multiphase CT in facilitating patient selection and surgical planning in potential donors being evaluated for living adult right lobe liver transplantation.

SUBJECTS AND METHODS

Forty consecutive potential donors were included in the study. There were 26 men and 14 women, (age range, 18-57 years; mean, 37 years) We performed CT using a multidetector scanner, after IV injection of 180 mL of contrast material at 5 mL/sec. Arterial phase images were acquired at 18 sec (collimation, 1.25 mm; table speed, 7.5) and portal phase images, at 60 sec (collimation, 2.5 mm; table speed, 15). Postprocessing was performed on a commercially available workstation. CT data included dual-energy assessment of liver parenchyma for fatty infiltration; depiction of arterial, portal venous, and hepatic venous anatomy and identification of important vascular variants; and determination of total and lobar liver volume.

RESULTS

Of the 40 potential liver donors evaluated, 15 patients (37.5%) were excluded on the basis of CT findings, with most exclusions a result of portal vein anomalies (n = 8). Fatty infiltration resulted in four exclusions (10%), and small liver volume resulted in three exclusions (7.5%).

CONCLUSION

Multidetector multiphase CT provided comprehensive parenchymal, vascular, and volumetric preoperative evaluation of potential donors undergoing living adult right lobe liver transplantation. This information had a major impact on patient selection because it was used to stratify patients. It allowed the surgeons to plan their surgical approach, and this planning may reduce postoperative complications.

Evaluation of aberrant bile ducts before laparoscopic cholecystectomy: helical CT cholangiography versus MR cholangiography

OBJECTIVE

The purpose of our study was to compare the accuracy of helical CT cholangiography and that of MR cholangiography in the diagnosis of aberrant bile ducts or cystic ducts before laparoscopic cholecystectomy.

SUBJECTS AND METHODS

A total of 120 consecutive patients, including 114 patients with cholecystolithiasis and six with gallbladder polyps, were treated using laparoscopic cholecystectomy between November 1996 and August 1998. Eighteen (15%) of the 120 patients were suspected of having aberrant bile ducts or cystic ducts on helical CT cholangiography, and 16 of these 18 patients were subsequently examined on MR cholangiography. For the 16 patients who underwent both imaging examinations, findings from helical CT cholangiography and MR cholangiography were compared with intraoperative cholangiography.

RESULTS

Aberrant bile ducts in 13 patients and aberrant cystic ducts in three patients were divided into six types on the basis of the results of intraoperative cholangiography. Although these types were clearly identified using helical CT cholangiography in all 16 patients, the anatomic variants were not correctly identified in seven (44%) of the 16 patients with MR cholangiography. False-negative findings were mainly a result of the insertion sites of the cystic ducts or aberrant bile ducts being obscured by aberrant bile ducts or duodenum. Two (2%) of the 120 patients developed mild adverse reactions to the contrast material, but neither required treatment.

CONCLUSION

Helical CT cholangiography clearly showed aberrant bile ducts and cystic ducts, but visualization of these structures on MR cholangiography was unsatisfactory because of overlapping duodenum and hepatic ducts.

Preoperative assessment for laparoscopic cholecystectomy: feasibility of using spiral computed tomography

OBJECTIVE

The authors investigated the preoperative feasibility of using spiral computed tomography (SCT) after intravenous infusion cholangiography (IVC-SCT) for laparoscopic cholecystectomy.

SUMMARY BACKGROUND DATA

In laparoscopic cholecystectomy, the aberrant or unusual anatomy of the bile duct and severe inflammation or adhesions around the gallbladder sometimes require a conversion to open surgery.

METHODS

Laparoscopic cholecystectomies (LC's) were attempted on 440 patients, and preoperative IVC-SCT also was attempted in all of these patients. Using this spiral scanning technique, the bile ducts, cystic duct, and gallbladder were assessed for contour abnormalities, relative position, and filling defects. Forty-seven patients were diagnosed with having stones in their common bile duct or common hepatic duct.

RESULTS

Three-hundred eighty-seven patients out of the 440 patients (88.0%) who were subjected to IVC-SCT had the length and course of their cystic duct successfully determined. Anomalous unions of the cystic duct were seen in 59 (15.2%) of 387 patients with respect to the operative findings, and 48 of 440 patients (10.9%) had severe adhesions to Calot's triangle and the surrounding tissues. In these 48 patients, 45 patients (94%) had a nonvisualized cystic duct on IVC-SCT. The preoperative assessment of the feasibility (dense adhesions obscuring Calot's triangle) of using IVC-SCT demonstrated that the sensitivity, specificity, and accuracy were 93%, 98%, and 94%, respectively. Five patients had to be converted to open surgery, and the overall morbidity rates for patients undergoing laparoscopic cholecystectomy was 0.9% (4 of 440).

CONCLUSIONS

The most important factor in assessing the feasibility of using laparoscopic cholecystectomy is not the nonvisualized gallbladder, but the nonvisualized cystic duct on IVC-SCT. IVC-SCT may be of benefit to those patients scheduled to undergo laparoscopic cholecystectomy.

Spiral computed tomography scanning after intravenous infusion cholangiography for biliary duct anomalies

BACKGROUND

Iatrogenic injury of the bile duct during cholecystectomy represents a failure of surgical technique, especially for laparoscopic surgery. Knowledge of the patient's individual ductal anatomy and anomalies preoperatively would be helpful in avoiding such injuries. Therefore, we investigated the anatomy of the biliary duct and any anomalies using spiral computed tomography (SCT) scanning following intravenous infusion cholangiography (IVC-SCT).

MATERIALS

Laparoscopic cholecystectomies (LC) were attempted on 437 patients at the Kansai Medical University. Preoperative IVC-SCT and laparoscopic cholangiography were attempted in all of the patients.

RESULTS

An overall anomalous union of the cystic duct was seen in 71 (16.2%) out of the 437 patients subjected to IVC-SCT. The following anomalies were observed: right hepatic duct entry in 7 cases (1.6%), parallel low entry in 17 cases (3.9%), posterior spiral entry in 35 cases (8.0%), anterior spiral entry in 7 cases (1.6%), and accessory duct entry in 5 cases (1.1%). The success rate for the LC was 99.5% (435/437). Three patients were switched to open surgery owing to advanced gallbladder cancer and severe adhesions. The success rate for the laparoscopic cholangiography was 97.2% (423 of 435). Intraoperative right hepatic duct injury occurred in only 1 patient with a bile duct anomaly, and it was repaired with laparoscopic T-tube drainage.

CONCLUSIONS

The preoperative examination of the biliary tract by IVC-SCT was technically simple, less invasive, and may helpful in avoiding damage to the bile duct, especially in patients with biliary duct anomalies.