New technique using intraductal ultrasonography for the diagnosis of bile duct cancer

Recent Advancement in Diagnosis of Biliary Tract Cancer through Pathological and Molecular Classifications

Biliary tract cancers (BTCs), including intrahepatic, perihilar, and distal cholangiocarcinomas, as well as gallbladder cancer, are a diverse group of cancers that exhibit unique molecular characteristics in each of their anatomic and pathological subtypes. The pathological classification of BTCs compromises distinct growth patterns, including mass forming, periductal infiltrating, and intraductal growing types, which can be identified through gross examination. The small-duct and large-duct types of intrahepatic cholangiocarcinoma have been recently introduced into the WHO classification. The presentation of typical clinical symptoms, as well as the extensive utilization of radiological, endoscopic, and molecular diagnostic methods, is thoroughly detailed in the description. To overcome the limitations of traditional tissue acquisition methods, new diagnostic modalities are being explored. The treatment landscape is also rapidly evolving owing to the emergence of distinct subgroups with unique molecular alterations and corresponding targeted therapies. Furthermore, we emphasize the crucial aspects of diagnosing BTC in practical clinical settings.

Endoscopic Perspective in Cholangiocarcinoma Diagnostic Process

Cholangiocarcinoma is a malignancy arising from the epithelial lining of the intrahepatic or extrahepatic biliary tract. Timely diagnosis is challenging due to its silent clinical course. As reliable laboratory markers are lacking, diagnostic imaging plays a pivotal role. While cross-sectional imaging studies are usually conclusive for intrahepatic lesions, endoscopy plays an essential role in cases of extrahepatic tumors. Rational utilization of different diagnostic methods based on available evidence is needed. This article focuses on the diagnostic role of advanced biliary endoscopy, including endoscopic retrograde cholangiopancreatography, cholangioscopy, endoscopic ultrasonography, and intraductal sonography.

Intraductal ultrasonographic anatomy of biliary varices in patients with portal hypertension

BACKGROUND AND OBJECTIVES

The term, portal biliopathy, denotes various biliary abnormalities, such as stenosis and/or dilatation of the bile duct, in patients with portal hypertension. These vascular abnormalities sometimes bring on an obstructive jaundice, but they are not clear which vessels participated in obstructive jaundice. The aim of present study was clear the bile ductal changes in patients with portal hypertension in hopes of establishing a therapeutic strategy for obstructive jaundice caused by biliary varices.

MATERIALS AND METHODS

Three hundred and thirty-seven patients who underwent intraductal ultrasound (IDUS) during endoscopic retrograde cholangiography for biliary abnormalities were enrolled. Portal biliopathy was analyzed using IDUS.

RESULTS

Biliary varices were identified in 11 (2.7%) patients. IDUS revealed biliary varices as multiple, hypoechoic features surrounding the bile duct wall. These varices could be categorized into one of two groups according to their location in the sectional image of bile duct: epicholedochal and paracholedochal. Epicholedochal varices were identified in all patients, but paracholedochal varices were observed only in patients with extrahepatic portal obstruction.

CONCLUSION

IDUS was useful to characterize the anatomy of portal biliopathy in detail.

Contrast-enhanced endoscopic ultrasonography in digestive diseases

Contrast-enhanced endoscopic ultrasonography (CE-EUS) was introduced in the early 1990s. The concept of the injection of carbon dioxide microbubbles into the hepatic artery as a contrast material (enhanced ultrasonography) led to "endoscopic ultrasonographic angiography". After the arrival of the first-generation contrast agent, high-frequency (12 MHz) EUS brought about the enhancement of EUS images in the diagnosis of pancreatico-biliary diseases, upper gastrointestinal (GI) cancer, and submucosal tumors. The electronic scanning endosonoscope with both radial and linear probes enabled the use of high-end ultrasound machines and depicted the enhancement of both color/power Doppler flow-based imaging and harmonic-based imaging using second-generation contrast agents. Many reports have described the usefulness of the differential diagnosis of pancreatic diseases and other abdominal lesions. Quantitative evaluation of CE-EUS images was an objective method of diagnosis using the time-intensity curve (TIC), but it was limited to the region of interest. Recently developed Inflow Time Mapping™ can be generated from stored clips and used to display the pattern of signal enhancement with time after injection, offering temporal difference of contrast agents and improved tumor characterization. On the other hand, three-dimensional CE-EUS images added new information to the literature, but lacked positional information. Three-dimensional CE-EUS with accurate positional information is awaited. To date, most reports have been related to pancreatic lesions or lymph nodes. Hemodynamic analysis might be of use for diseases in other organs: upper GI cancer diagnosis, submucosal tumors, and biliary disorders, and it might also provide functional information. Studies of CE-EUS in diseases in many other organs will increase in the near future.

Endoscopic retrograde cholangioscopy and advanced biliary imaging

Developments in endoscopic retrograde cholangioscopy provide multiple new advanced methods of biliary imaging. Cholangioscopy provides direct visualization of epithelium with white light as well as advanced modalities, such as narrow band imaging and autofluorescence. In vivo histologic images can be achieved with confocal endomicroscopy. Cross-sectional imaging is also possible with intraductal ultrasonography and optical coherence tomography. This article describes these advanced imaging techniques, which can be used together to assist in the diagnosis of biliary strictures and lesions.

Endoscopic diagnosis of extrahepatic bile duct carcinoma: Advances and current limitations

The accurate diagnosis of extrahepatic bile duct carcinoma is difficult, even now. When ultrasonography (US) shows dilatation of the bile duct, magnetic resonance cholangiopancreatography followed by endoscopic US (EUS) is the next step. When US or EUS shows localized bile duct wall thickening, endoscopic retrograde cholangiopancreatography should be conducted with intraductal US (IDUS) and forceps biopsy. Fluorescence in situ hybridization increases the sensitivity of brush cytology with similar specificity. In patients with papillary type bile duct carcinoma, three biopsies are sufficient. In patients with nodular or infiltrating-type bile duct carcinoma, multiple biopsies are warranted, and IDUS can compensate for the limitations of biopsies. In preoperative staging, the combination of dynamic multi-detector low computed tomography (MDCT) and IDUS is useful for evaluating vascular invasion and cancer depth infiltration. However, assessment of lymph nodes metastases is difficult. In resectable cases, assessment of longitudinal cancer spread is important. The combination of IDUS and MDCT is useful for revealing submucosal cancer extension, which is common in hilar cholangiocarcinoma. To estimate the mucosal extension, which is common in extrahepatic bile duct carcinoma, the combination of IDUS and cholangioscopy is required. The utility of current peroral cholangioscopy is limited by the maneuverability of the “baby scope”. A new baby scope (10 Fr), called “SpyGlass” has potential, if the image quality can be improved. Since extrahepatic bile duct carcinoma is common in the Far East, many researchers in Japan and Korea contributed these studies, especially, in the evaluation of longitudinal cancer extension.

Intraductal ultrasonography (IDUS) for the diagnosis of biliopancreatic diseases

Intraductal ultrasonography (IDUS) is an imaging modality having unique characteristics and suitable for imaging of a narrow ductal cavity, its wall and the neighbouring structures. As IDUS uses high-frequency ultrasound (12-30MHz), its image quality is very high within approximately 2-cm range of radius. The bile duct and the pancreatic duct, therefore, are good targets for the assessment by IDUS. Biliopancreatic IDUS is mainly performed through the papilla of Vater in the same session as endoscopic retrograde cholangiopancreatography (ERCP). Biliary IDUS is possible through the percutaneous transhepatic route as well. Not many comparative studies on biliopancreatic IDUS have been published. Gallbladder IDUS as well as most pancreatic IDUS are still at the level of clinical research. Constant delineation of Oddi's sphincter with the improvement of instruments will expand the use of IDUS for the assessment of the papilla of Vater lesions.

Clinical application of intraductal ultrasound during endoscopic retrograde cholangiopancreatography

Intraductal ultrasound (IDUS) used during endoscopic retrograde cholangiopancreatography (ERCP) can facilitate reliable evaluation of biliary and pancreatic disorders. The smaller diameter, flexibility, and the image quality offered by IDUS devices makes them ideal for evaluating a variety of difficult biliary and pancreatic diseases, especially in undefined strictures, luminal filling defects, and ampullary neoplasms. This article examines the numerous possible roles for IDUS in the evaluation of biliary and pancreatic conditions, as well as in ampullary neoplasms. IDUS is a simple, easy to learn, and safe technique that should be considered an integral tool in the therapeutic endoscopist's armamentarium.

Intraductal sonography of biliary varices associated with extrahepatic portal vein obstruction

We report a case of biliary varices associated with extrahepatic portal vein obstruction (EHPVO) that were identified via intraductal sonography during endoscopic retrograde cholangiography. A 35-year-old man was admitted to our hospital because of jaundice that had developed during an episode of EHPVO. Laboratory data showed obstructive jaundice. Endoscopic retrograde cholangiography showed some bile duct stenosis with smooth stricture along the extrahepatic biliary duct. Intraductal sonographic examination revealed numerous vessels around the lower and upper parts of the bile duct. Compression by these vessels was suspected as the cause of the biliary stricture.

Evaluation of normal bile duct and cholangitis by intraductal ultrasonography

BACKGROUND

The intraductal ultrasonographic findings of normal bile duct and cholangitis were examined.

METHODS

We studied 9 autopsy cases and evaluated the clinical records of 76 patients who had been subjected to papillotomy for bile duct stones removal retrospectively.

RESULT

In vitro study: Under a low pressure, the bile duct wall was thick, and the inner surface and outer contour were irregular. The wall became thinner, and the inner surface and outer contour became smooth as the pressure was increased. The thickness was 0.68 +/- 0.12 mm (mean +/- SD) all along the duct at all pressure, and 0.55 +/- 0.12 mm at a pressure above 15 cm H(2)O. The internal echo was homogenous regardless of the internal pressure used. In vivo study: We could evaluate in 70 patients (92.1%). The wall was 1.30 +/- 0.77 mm thick. There was no relationship between the severity of cholangitis and the wall thickness. The irregular inner surface, heterogeneous internal echo, and irregular outer contour correlated with the severity of cholangitis.

CONCLUSION

The normal bile duct wall was between 0.31 and 0.79 mm thick, the inner and outer surfaces were smooth, and internal echo was homogenous. An irregular inner surface, heterogeneous internal echo and an irregular outer contour were important findings of severe cholangitis.

Progress of endoscopic ultrasonography and intraductal ultrasonography in the diagnosis of malignant biliary diseases

In recent years, ultrasound technology has made remarkable strides, and the application of these latest advances to endoscopic ultrasonography (EUS) and intraductal ultrasonography (IDUS) is crucially important. EUS equipped with electronic scanners (both radial and convex types) has been developed, and now EUS with the function of tissue harmonic imaging (THI) and color/power Doppler is applicable clinically. THI facilitates the acquisition of ultrasound images clearer than those of fundamental imaging, and color/power Doppler sonography demonstrates the precise hemodynamics with the use of a contrast agent. In addition, the progress of image processing technology has realized three-dimensional (3D) images in EUS and IDUS. Reconstruction of 3D images enables us to diagnose more objectively. Here we describe the roles of these new ultrasound technologies in the diagnosis of biliary malignancies.

Intraductal US in assessing the effects of radiation therapy and prediction of patency of metallic stents in extrahepatic bile duct carcinoma

BACKGROUND

We assessed the local effects of radiation therapy using intraductal ultrasonography (US) to predict the subsequent patency of metallic stents in bile duct carcinoma.

METHODS

Data from 16 patients with extrahepatic-suprapancreatic bile duct carcinoma were prospectively analyzed. Thin-caliber US probes (2.0 mm diameter/20 MHz frequency and 2.8 mm diameter/10 MHz frequency) were inserted into the bile duct via a percutaneous transhepatic approach pre- and postradiation therapy to evaluate the effects of treatment. When intraductal US showed a reduction in bile duct wall thickness of 30% or greater or showed a lessening of vessel (portal vein or right hepatic artery) invasion, radiation therapy was judged to be effective. Noncovered metallic stents were then inserted, and their patency was evaluated over time.

RESULTS

When radiation therapy was effective (n = 7), the metallic stent was patent for 522 +/- 571 days. When radiation was ineffective (n = 9), the metallic stent was patent for only 188 +/- 159 days. When radiation therapy was ineffective, stent obstruction occurred in 6 of 9 (66.7%) patients during this period, significantly more frequently than when radiation therapy was effective (14.3%, p < 0.05).

CONCLUSIONS

Assessment of local radiation effects by intraductal US is useful for predicting patency of metallic stents in bile duct cancer.

Prospective evaluation of an over-the-wire catheter US probe

BACKGROUND

Pancreaticobiliary strictures identified at endoscopic retrograde cholangiopancreatography (ERCP) can be evaluated by intraductal ultrasonography (US). Two major difficulties are that sphincterotomy may be required and the stricture may not be traversable. We prospectively evaluated the ease and success of intraductal US using a new over-the-wire catheter US probe.

METHODS

Biliary or pancreatic strictures discovered at ERCP were imaged with the new probe. Intraductal US performance times, image clarity, imaging depth and technical ease were measured.

RESULTS

Twenty-one patients with a variety of inflammatory and malignant pancreaticobiliary lesions were studied. Thirteen of the 16 (81%) masses imaged by intraductal US were 10 mm or less in diameter. Sphincterotomy was not required. All strictures traversed by a guidewire were imaged. The sphincter of Oddi was successfully imaged in all patients with intact normal sphincters. Performance of intraductal US was rated as technically easy in all cases and image clarity was rated as good or very good in 15 of 21 (71%) cases.

CONCLUSIONS

The new over-the-wire catheter US probe facilitates intraductal US. Sphincterotomy is avoided and strictures are successfully traversed. This probe makes it possible to image the sphincter of Oddi.

Preoperative assessment of extrahepatic bile duct carcinoma using three-dimensional intraductal US

BACKGROUND

We investigated the utility of a new imaging modality, three-dimensional intraductal ultrasonography (US), for staging bile duct cancer.

METHODS

In eight patients with extrahepatic bile duct carcinoma, two- and three-dimensional intraductal US was used to assess tumor invasion of the right hepatic artery, portal vein, and pancreatic parenchyma before resection. The findings were correlated with histologic information from the resected specimen.

RESULTS

Three-dimensional intraductal US enabled accurate assessment of tumor invasion of the right hepatic artery in 88% of cases, the portal vein in 100%, and pancreatic parenchyma in 100%. Two-dimensional intraductal US enabled accurate assessment of invasion of these structures in 88%, 88%, and 88% of cases.

CONCLUSIONS

Three-dimensional intraductal US is useful in assessing tumor stage in bile duct carcinoma.

Preoperative assessment of congenital bile duct dilatation using intraductal US

BACKGROUND

Although congenital bile duct dilatation is frequently associated with biliary tract cancer, conventional cholangiography often does not demonstrate small ductal tumors. This is the first prospective study of the value of intraductal ultrasonography (US) in the examination of the extrahepatic bile ducts in patients with congenital bile duct dilatation.

METHODS

Intraductal US via a transpapillary route was used in consecutive patients with congenital bile duct dilatation. A 2.0 mm diameter, 20 MHz frequency catheter probe was used. The images were correlated with the results of histologic examination of the resection specimens.

RESULTS

Intraductal US was performed successfully via the transpapillary route in 8 of 10 patients. In the other 2 patients, the percutaneous transhepatic route was used. In the 6 patients with cylindrical dilatation, intraductal US demonstrated the entire extrahepatic bile duct. In 1 patient, it showed a bile duct cancer not demonstrated by cholangiography. In 2 of the 4 patients with cystic dilatation, intraductal US did not demonstrate the entire extrahepatic bile duct because of the low penetration depth of the probe. Percutaneous transhepatic cholangioscopy was required in these patients.

CONCLUSIONS

Intraductal US is useful for demonstrating cancers in the extrahepatic bile ducts in patients with congenital cylindrical ductal dilatation.

Assessment of residual bile duct stones with use of intraductal US during endoscopic balloon sphincteroplasty: comparison with balloon cholangiography

BACKGROUND

We sought to determine the utility of intraductal ultrasonography (IDUS) in detecting residual bile duct stones during endoscopic balloon sphincteroplasty.

METHODS

Eighty-one consecutive patients with bile duct stones who underwent IDUS during endoscopic balloon sphincteroplasty were studied. IDUS was performed with a thin-caliber ultrasonic probe (diameter 2.0 mm, frequency 20 MHz) by a transpapillary route after stone extraction. When IDUS or balloon-retrograde cholangiography suggested residual stones, the bile duct was cleared again with a Dormia basket. Extraction of the stones was confirmed by direct duodenoscopic visualization. Videotapes of IDUS and cholangiograms were reviewed retrospectively without knowledge of the results of other diagnostic modalities.

RESULTS

In 27 of 81 patients (33%), IDUS detected small residual stones not seen on cholangiography. When stones were fragmented with mechanical lithotripsy, the accuracy of IDUS in detecting small residual stones was significantly greater than that of balloon-endoscopic retrograde cholangiography (95% vs 50%, p < 0. 001). When the bile duct was greater than 10 mm in diameter, the accuracy of IDUS in detecting small residual stones was significantly greater than that of cholangiography (92% vs. 56%, p < 0.001).

CONCLUSIONS

IDUS is useful for detecting small residual bile duct stones during endoscopic balloon sphincteroplasty when stones are fragmented by mechanical lithotripsy or when there is evidence of a dilated bile duct (>10 mm).

Bile duct wall thickness measured by intraductal US in patients who have not undergone previous biliary drainage

BACKGROUND

We investigated the bile duct wall thickness measured on intraductal US in patients who had not undergone biliary drainage, with special attention to the influence of cancer at the distal bile duct, bile duct stones, obstructive jaundice, longitudinal cancer extension, and primary sclerosing cholangitis on wall thickness.

METHODS

The study included 183 patients. Patients who had undergone previous biliary drainage were excluded. Intraductal US was performed by the transpapillary route with use of a thin-caliber ultrasonic probe (2.0 mm diameter, 20 MHz frequency). The bile duct wall thickness (width of the inside hypoechoic layer) was retrospectively measured on US images.

RESULTS

Bile duct wall thicknesses of the common hepatic duct for the control group (n = 95), cancer at the distal bile duct group (n = 9), bile duct stone group (n = 56), and obstructive jaundice group (n = 17) were 0.6 +/- 0.3 mm (mean +/- SD), 0.8 +/- 0.5 mm, 0.8 +/- 0.6 mm, and 0.8 +/- 0. 5 mm, respectively. No significant differences (p > 0.05) were found between them. However, wall thickness for the cancer extension to the common hepatic duct group (n = 4, 2.0 +/- 0.4 mm) and sclerosing cholangitis group (n = 2, 2.5 +/- 0.4 mm) were significantly greater than in the other groups (p < 0.005).

CONCLUSIONS

In patients who have not undergone previous biliary drainage, the bile duct wall thickness was not thicker in patients with obstructive jaundice. However, the duct wall was significantly thicker in patients with either longitudinal cancer extension or primary sclerosing cholangitis compared with that of other groups.

Intraductal ultrasonography for the diagnosis of proximal invasion in extrahepatic bile duct cancer

Intraductal ultrasonography (IDUS) was performed on 22 patients with extrahepatic bile duct cancer, using the percutaneous transhepatic approach. Intraductal ultrasonography images of the proximal invasion of the bile duct cancer were defined. In addition, three patients were examined through the peroral approach, to try to diagnose whether or not the cancer invaded to the bifurcation of the hepatic duct. Intraductal ultrasonography images obtained through the percutaneous approach could be classified into three patterns, types 1, 2 and 3, according to the features of the interior surface of the bile duct and the thickness of the bile duct wall. Type 1 images, which did not show protrusions into the bile duct lumen and had a bile duct wall of even thickness, were not likely to show bile duct cancer. Type 2 images showed protrusions of the tumour into the bile duct lumen and the surfaces of the protrusions were irregular. Type 3 images showed single or multiple low echoic papillary masses in the bile duct. Using the peroral technique, we considered all three cases to be type 1 and could diagnose that cancer had not invaded to the bifurcation of the hepatic ducts. From the results of this study, we suggest that proximal invasion of extrahepatic bile duct cancer can be diagnosed using IDUS.

Characterization of biliary strictures using intraductal ultrasonography: comparison with percutaneous cholangioscopic biopsy

BACKGROUND

We determined the accuracy of intraductal ultrasonography (IDUS) in distinguishing between bile duct cancer and benign bile duct disease.

METHODS

Patients (n=42) who required bile duct biopsy using percutaneous transhepatic cholangioscopy (PTCS) to evaluate bile duct strictures or filling defects were studied. A thin-caliber ultrasonic probe (2.0 mm diameter and 20 MHz frequency) was inserted into the bile duct, and its images were prospectively reviewed before PTCS.

RESULTS

Disruption of the bile duct wall structure, seen on IDUS, was associated with malignancy in 25 of 26 patients. When IDUS demonstrated a lesion with normal bile duct structure, six of nine patients were found to have no malignancy. IDUS demonstrated no intraductal lesion in seven patients, and bile duct biopsy also did not indicate cancer in any of these patients. The accuracy, sensitivity, and specificity of IDUS for diagnosing bile duct cancer were 76%, 89%, and 50%, respectively. When used in tandem with IDUS, the sensitivity of bile cytology (64%) and PTCS (93%) improved to 96% and 100%, respectively.

CONCLUSIONS

The accuracy of IDUS for diagnosing bile duct cancer was less than that of PTCS (95%). However, the sensitivity for bile cytology, or bile duct biopsy improved when performed in combination with IDUS.

Intraportal endovascular ultrasonography for assessment of vascular invasion by biliary tract cancer

BACKGROUND

This study was performed to investigate the diagnostic accuracy of intraportal endovascular ultrasonography (IPEUS) in assessing vascular invasion by biliary tract cancer.

METHODS

A prospective study of 31 consecutive patients with biliary tract cancer was performed. All patients underwent surgery. The sonographic criterion for right hepatic artery invasion was interruption of the hyperechoic layer or encasement by tumor. The sonographic criterion for portal vein invasion was obliteration of the echogenic band of the portal vein. IPEUS findings were confirmed by surgical exploration and pathologic examination of resected specimens.

RESULTS

Right hepatic artery invasion was confirmed in resected specimens in seven patients and by operative findings in four patients. Portal vein invasion was confirmed in resected specimens in six patients and by operative findings in five patients. For diagnosis of right hepatic artery invasion, the sensitivity, specificity, and overall accuracy of IPEUS were all 100%; respective values were 63.6%, 84.2%, and 76.7% for angiography. For diagnosis of portal vein invasion, the sensitivity, specificity, and overall accuracy of IPEUS were 100%, 95%, and 96.8%, respectively. The corresponding values were 63.6%, 89.5%, and 80% for portography and 54.5%, 85%, and 74.2%, respectively, for CT.

CONCLUSION

IPEUS will improve the assessment of vascular invasion at the hepatic hilum by biliary tract cancer.

Influence of biliary drainage catheter on bile duct wall thickness as measured by intraductal ultrasonography

OBJECTIVE

To determine the influence of biliary drainage catheter placement on bile duct wall thickness, we performed intraductal ultrasonography (IDUS) in patients before and after biliary drainage.

METHODS

Patients underwent IDUS before and after either short-term (n = 9, 6 to 8 days) or long-term (n = 9, 14 to 35 days) biliary drainage using a thin (2.0 mm diameter), 20 MHz probe inserted by means of a transpapillary route or a percutaneous tract. The bile duct wall thickness (mean +/- standard deviation) was retrospectively measured at the upper portion of the common hepatic duct.

RESULTS

The bile duct wall thickness increased from 0.8+/-0.4 mm (predrainage) to 2.0+/-1.6 mm (post-drainage) in the long-term group (p < 0.001) but was not significantly increased in the short-term group.

CONCLUSIONS

The bile duct wall thickness as measured on IDUS appears to be increased after placement of biliary drainage catheters.

Intraductal ultrasonography in diagnosing tumor extension of cancer of the papilla of Vater

BACKGROUND

Intraductal ultrasonography is clinically useful in assessing various pancreatobiliary diseases. This study was carried out to evaluate the usefulness of intraductal ultrasonography in diagnosing tumor extension of cancer of the papilla of Vater.

METHODS

Thirty-two patients with cancer underwent intraductal ultrasonography. According to the spatial relationship between the tumor echo and the hypoechoic layers representing Oddi's muscle layer or the duodenal muscularis propria layer, the images were classified into four grades. We attempted to diagnose tumor extension using this grading system. Lymph nodes measuring over 10 mm were evaluated as involved. Findings were compared with postoperative histopathologic findings classified as follows: d0, tumor limited to Oddi's muscle layer; d1, tumor invading the duodenal submucosal layer; d2, tumor invading the duodenal muscularis propria layer; and panc(+), tumor invading the pancreas.

RESULTS

Diagnostic accuracy rate was 100% (6 of 6) in d0 cases, 92.3% (12 of 13) in d1 cases, 100% (1 of 1) in a d2 case, and 75% (9 of 12) in panc(+) cases. Overall accuracy rate was 87.5% (28 of 32). In assessing lymph node metastases, sensitivity was 66.7% (6 of 9) and specificity was 91.3% (21 of 23).

CONCLUSION

Intraductal ultrasonography examination is useful in diagnosing tumor extension of cancer of the papilla of Vater.

Assessment of the course and variations of the hepatic artery in bile duct cancer by intraductal ultrasonography

BACKGROUND

We evaluated the course and variations of the hepatic artery in bile duct cancer using intraductal ultrasonography (IDUS).

METHODS

IDUS was used to demonstrate the course of the hepatic artery preoperatively in 20 patients with extrahepatic bile duct cancer, and the image was compared with angiographic and surgical findings.

RESULTS

IDUS was able to assess tumor invasion to the main branch of the right hepatic artery in all cases. However, it demonstrated only three cases in the left hepatic artery and four cases in the proper hepatic artery. When the hepatic artery indicated re-entry or bifurcation on the IDUS image, the proximal portion of re-entry or bifurcation was established as the proper hepatic artery, but when it showed neither re-entry nor bifurcation it was established as the right hepatic artery.

CONCLUSIONS

IDUS demonstrated the main branch of the right hepatic artery in all cases, but was not useful for demonstration of the left and proper hepatic arteries. Correct assessment of re-entry and bifurcation was essential on IDUS images for making the distinction between the right hepatic artery and the proper hepatic artery.

Extrapancreatic nerve plexus invasion by carcinoma of the head of the pancreas. Diagnosis with intraportal endovascular ultrasonography

CONCLUSION

The intraportal endovascular ultrasonography (IPEUS) could diagnose the second portion of the extrapancreatic nerve plexus invasion and provide precise information in operative strategy. But, the first portion was not visualized clearly owing to poor tissue penetration of the ultrasound beam, which may have reduced diagnostic accuracy. Improvement of the scanning area is expected to make intraportal endovascular US even more useful.

BACKGROUND

Pancreatic cancer easily invades the retroperitoneal tissue, especially the extrapancreatic nerve plexus. We evaluated the extrapancreatic nerve plexus invasion of the pancreatic cancer with IPEUS. IPEUS was performed intraoperatively in 20 consecutive resected cases with carcinoma of the head of the pancreas.

METHODS

IPEUS was performed with an 8-French, 20 MHz intravascular ultrasound catheter. IPEUS visualized the inferior pancreaticoduodenal artery (IPDA) in the extrapancreatic nerve plexus. The high-echoic area around the IPDA corresponds to the second portion of the extrapancreatic nerve plexus. The sonographic criterion for detection of the extrapancreatic nerve plexus invasion is low-echoic infiltration around the IPDA.

RESULTS

Extrapancreatic nerve plexus invasion was confirmed with resected specimens in 10 patients. The IPDA could not be visualized in two patients. In 18 patients, the diagnostic accuracy of invasion was evaluated. For diagnosis of extrapancreatic nerve plexus invasion with intraportal endovascular US, the sensitivity, specificity, and overall accuracy were 87.5, 90, and 88.7%, respectively.

Intracaval ultrasonography in the diagnosis of tumour involvement of the vena cava

A retrospective study of 34 consecutive patients with possible tumour involvement of the vena cava was performed to assess the usefulness of intracaval ultrasonography. Twenty-five of the 34 patients were operated and resection carried out in 23, including seven with combined resection of the vena cava. The sonographic criterion for vena cava invasion was obliteration of the echogenic ring of the vena cava wall or intracaval tumour mass. The sensitivity, specificity and overall accuracy of intracaval endovascular ultrasonography in the diagnosis of tumour involvement of the vena cava were 100, 96 and 97 per cent respectively. The respective values were 91, 61 and 71 per cent for computed tomography and 82, 67 and 72 per cent for cavography. Ultrasonography is a useful technique that can precisely evaluate the vena cava for possible tumour invasion, especially when the presence or extent of tumour involvement is not definitely established by conventional imaging techniques.