Limitations of three-dimensional intraductal ultrasonography in the assessment of longitudinal spread of extrahepatic bile duct carcinoma

Controversies in EUS: Do we need miniprobes?

This is the fifth in a series of papers entitled "Controversies in EUS." In the current paper, we deal with high-resolution catheter probes, otherwise known as EUS miniprobes (EUS-MPs). The application of miniprobes for early carcinomas in the entire intestinal tract, for subepithelial lesions, and for findings in the bile duct and pancreatic duct as well as endobronchial use is critically discussed. Submucous lesions, especially in the colon, but also early carcinomas in special cases are considered the most important indications. The argument is illustrated by numerous examples.

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.

Cholangioscopy: where are we now?

PURPOSE OF REVIEW

The purpose of this review is to provide an update on current technologies and clinical indications for cholangioscopy. The review also focuses on techniques, challenges and limitations of available devices.

RECENT FINDINGS

Recent technological advances such as the introduction into clinical practice of video cholangioscopes as well as a single-operator semidisposable per oral cholangioscope are described. Novel clinical applications of cholangioscopy are also discussed.

SUMMARY

The past several years have witnessed the emergence of new technologies, including video and semidisposable cholangioscopes, which have increased the availability and utilization of cholangioscopes. Although the most common indications for this technique remain investigation of indeterminate cholangiographic findings and management of large bile duct stones, technological advances in the devices and available accessories will invariably lead to expanded indications in the future.

Malignant biliary obstruction: value of imaging findings

This review focuses on the clinical impact of different modalities to image primary and secondary malignant biliary obstruction. The detection and staging of cancers of the pancreatic and biliary tract are best accomplished with endoscopic ultrasound, contrast-enhanced computed tomography, and magnetic resonance cholangiopancreatography. Three-dimensional ultrasound is a new noninvasive method that may be used increasingly as an initial test to select patients who require further diagnostic evaluation by magnetic resonance cholangiopancreatography or therapeutic endoscopic retrograde cholangiopancreatography. All-in-one computed tomography including three-dimensional reconstructions of the biliary tree may be competitive against all-in-one magnetic resonance imaging for diagnosis and staging of pancreatic tumors. Magnetic resonance cholangiopancreatography is excellent for identifying the presence and the level of biliary obstruction. With newer diagnostic imaging technologies emerging, endoscopic retrograde cholangiopancreatography is evolving into a predominantly therapeutic procedure.

Cholangiocarcinoma and intraductal sonography

The instruments and processing systems of intraductal ultrasonography (IDUS) and 3D-IDUS are developing. IDUS is a reliable method for the evaluation of cholangiocarcinoma, and accurate staging is the most significant role of IDUS. DPR images produced by 3D-IDUS are useful to assess the tumor extension and the relationship with surrounding organs. 3D-IDUS is more useful for the precise diagnosis of cancer extension in cholangiocarcinoma, especially in invasion into the portal vein and pancreas, than CT scan and angiography. Tumor volume calculated with 3D-IDUS should determine the prognosis for the patients and facilitate the evaluation of efficacy of laser therapy.

Intraductal ultrasonography for hepatocellular carcinoma with tumor thrombi in the bile duct: comparison with polypoid cholangiocarcinoma

BACKGROUND AND AIM

Tumor thrombi in the bile duct caused by hepatocellular carcinoma (HCC), and cholangiocarcinoma show polypoid lesions on cholangiographic findings. This study prospectively compared the images of intraductal ultrasonography between HCC and polypoid cholangiocarcinoma.

METHODS

In five patients with tumor thrombi in the bile duct caused by HCC, a 2.0 mm diameter ultrasonic probe with a frequency of 20 MHz was inserted into the bile duct via the transpapillary route (n = 4) or the transhepatic route (n = 1). The images were compared to that of 65 patients with cholangiocarcinoma.

RESULTS

In all patients with HCC, intraductal ultrasonography showed a 'polypoid tumor with a narrow base'. In 16 of 65 patients with cholangiocarcinoma, it showed a 'polypoid tumor with a narrow base'. When intraductal ultrasonography showed a 'polypoid tumor with a narrow base', the findings of a positive 'nodule within a nodule' (40 vs 0%; P < 0.05), and the absence of a 'papillary-surface pattern' (80 vs 13%; P < 0.05) were more highly associated with tumor thrombi caused by HCC than to polypoid-type cholangiocarcinoma.

CONCLUSIONS

Intraductal ultrasonography was useful to distinguish between tumor thrombi caused by HCC and polypoid-type cholangiocarcinoma.