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

Diagnostic accuracy of endoscopic ultrasonography in patients with inconclusive magnetic resonance imaging diagnosis of biliopancreatic abnormalities

AIM

To determine the sensitivity and specificity of endoscopic ultrasonography (EUS) in patients with inconclusive magnetic resonance imaging/magnetic resonance cholangiopancreatography (MRI/MRCP) in pancreatobiliary abnormalities.

METHODS

During 10 months, patients with pancreatobiliary diseases referred to endoscopic retrograde cholangiopancreatography (ERCP) because of inconclusive MRI/MRCP diagnosis were scheduled to undergo endoscopic ultrasonography. Patients were divided into four major groups: patients with (i) resectable periampullary neoplasms who were referred to a surgeon, (ii) unresectable periampullary cancer who underwent ERCP for biliary stenting, (iii) bile duct stone who were referred to ERCP for stone extraction, and (iv) normal pancreatobiliary tract. Reference standards for comparison were ERCP, surgery, a biopsy confirming malignancy, or the clinical course during follow up (at least 12 months) in cases without evidences of malignancy.

RESULTS

One hundred and seven patients (51 men; mean [SD] age 60.0 [15.5]) were included in the study. Final diagnoses were common bile duct (CBD) stone (n = 24), periampullary neoplasms (n = 46), others (n = 23) and no pathologic findings (n = 14). EUS determined the staging for clinical decision-making in 47 patients with neoplasms which showed that tumors in 34 patients (79.1%) were unresectable (advanced stage). After EUS, 47 patients (43.9%) did not require ERCP. The accuracy of EUS for the diagnosis of CBD stone and periampullary neoplasms were 96.3% and 99.1%, respectively.

CONCLUSIONS

EUS is a useful modality in cases of inconclusive MRI/MRCP indicating pancreatobiliary disorders.

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.

Correct diagnosis of vascular encasement and longitudinal extension of hilar cholangiocarcinoma by four-channel multidetector-row computed tomography

Accurate diagnosis of local invasion of hilar cholangiocarcinomas is challenging due to their small size and the anatomic complexity of the hepatic hilar region. On the other hand, the correct diagnosis of local invasion is essential for assuring the possibility of curative surgery. The purpose of this study was to evaluate the feasibility of four-channel multidetector-row computed tomography (MDCT) in the assessment of vascular and bile duct involvement, by which we could obtain useful information for the surgical management of hilar cholangiocarcinoma. The subjects were 18 patients for whom the extent of tumor invasion was surgically and pathologically confirmed. All patients underwent preoperative multiphasic CT scanning by MDCT. Arterial and portal dominant phases were acquired using a detector configuration of 1.25 mm X 4 mm, and both axial and multiplanar reconstructed images were interpreted. Longitudinal extension was evaluated up to second-order branches. Vascular invasion is considered to be the degree of tumor contiguity to the hepatic arteries and portal vein and was graded by CT. The longitudinal extension was correctly diagnosed in 14 patients (77.8%). Hepatic artery invasion was correctly diagnosed in 17 patients with sensitivity of 100% and specificity of 90%, respectively. Portal vein invasion was correctly diagnosed in 47 of 51 branches with sensitivity and specificity of 92.3% and 90.2%, respectively. Multiplanar reconstructed images contributed to the correct diagnosis for both vascular encasement and longitudinal tumor extension. In conclusion, MDCT is useful in preoperative evaluation of hilar cholangiocarcinoma, especially when combined with multiplanar reconstructed images.

Intraductal US in the assessment of tumor involvement to the orifice of the cystic duct by malignant biliary obstruction

BACKGROUND

Tumor involvement to the orifice of the cystic duct (OCD) is a risk factor for cholecystitis after metallic stent (MS) placement.

OBJECTIVE

ERCP and intraductal US (IDUS) were used to assess tumor involvement to the OCD.

DESIGN

A prospective consecutive study.

SETTING

The University of Tokyo Hospital, Japan.

PATIENTS AND INTERVENTIONS

Between January 2003 and May 2007, 34 patients with resectable malignant biliary obstruction underwent an ERCP and an IDUS before preoperative biliary drainage.

MAIN OUTCOME MEASUREMENTS

ERCP and IDUS findings were confirmed via a histopathologic analysis of surgical specimens.

RESULTS

An ERCP showed that the cystic duct was opacified in 22 of 34 patients (64.7%). Eight patients were diagnosed with OCD tumor involvement. In the remaining 12 patients, tumor involvement was impossible to evaluate via an ERCP. An IDUS identified tumor involvement to the OCD in all 34 patients. Tumor involvement to the OCD was diagnosed in 12 patients, including 4 patients with previously negative results during an ERCP. Tumor involvement was confirmed by histopathology of surgical specimens. The sensitivity and specificity of detection were 66.7% (8/12) and 63.6% (14/22), respectively, via ERCP, and 100% (12/12) and 100% (22/22), respectively, via IDUS.

LIMITATION

The small sample size.

CONCLUSIONS

IDUS, in addition to ERCP, provides an accurate evaluation of tumor involvement to the OCD in patients with malignant biliary obstruction.

Clinicopathological study of patients undergoing resection of hilar cholangiocarcinoma

Of the patients who underwent resection of hilar cholangiocarcinoma, those who received palliative surgery, or could not be followed up clinicopathologically, were excluded from this study. In the remaining 37 patients, the cumulative postoperative survival rate (simply referred to as the cumulative survival rate below) was analyzed according to gross types, histopathological parameters, final stages, and final curability. These patients showed a 5-year survival rate of 17.7% and a 50% survival of 2.2 years. By gross type, patients with a localized papillary or nodular expansion type tended to have a better survival rate than those with an invasive papillary or nodular expansion type. A greater histological depth of invasion tended to be associated with a poorer prognosis: the s(-) group, that is, a group of patients without serosal exposure of cancer (invasion depths of m, fm, and ss) had a significantly better prognosis than the s(+) group, a group of patients with serosal exposure of cancer (invasion depths of se and si). Other histopathological parameters, such as ly, pn, pHinf, pHM, and pEM, were associated with significant prognostic differences. By final stage, the stage I/II group and stage III or higher group showed a particularly significant difference in prognosis. By final curability, the curability A/B group had a significantly better prognosis than the curability C group. Taken together, surgery providing curability A and B promises a good long-term prognosis. Therefore, it is important that efforts are made to detect cancer early, adequately evaluate the degree of cancer extension, and determine the extent of resection and the surgical technique.

Staging of cholangiocarcinoma: the role of endoscopy

The main question for staging is resectability, which is reliant on vascular, longitudinal, and metastatic spread. Today, accurate staging of perihilar tumors is achieved by non-invasive diagnostic investigations. Direct cholangiography has been the gold standard as a diagnostic procedure in recent decades. Endoscopic retrograde cholangiopancreaticography (ERCP) often only shows the ducts below the obstruction, and visualization of an obstructed part of the biliary tree is often not possible. Direct cholangiography reveals no information about local tumor extension, lymph nodes, or vascular involvement. Because of the given limitations, potential complications (cholangitis, sepsis) associated with direct cholangiography and reduction of the accuracy of subsequent cross-sectional imaging studies, these invasive techniques should only be used in the case of palliative interventions. Endoscopic ultrasonography-guided fine-needle aspiration (EUS-FNA) can be used to assess the nature of biliary strictures and to derive information about the extent of periductal disease and the presence of lymph node metastases. In a study by Fritscher-Ravens, 44 patients with hilar strictures underwent EUS-FNA. The overall diagnostic accuracy, sensitivity, specificity, positive and negative predictive values were 91% (95% CI, 78.4-96.3%), 89% (95% CI, 73.3-96.8%), 100% (95% CI, 63.1-100%), 100% (95% CI, 88.8-100%), and 67% (95% CI, 34.9-90%), respectively. The planned surgical approach was changed in 27 of 44 patients. In 15-20% of cholangiocarcinoma, patients with unremarkable abdominal imaging studies have metastatic lymph node involvement according to EUS evaluation. Due to the risk of peritoneal seeding, however, EUS with FNA is not recommended in patients still with a potential curative tumor.

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.

Duodenal EUS to identify thickening of the extrahepatic biliary tree wall in primary sclerosing cholangitis

BACKGROUND

Diagnosing primary sclerosing cholangitis (PSC) is problematic and requires meeting a burden of proof through clinical, biochemical, radiologic, and histological features. Endoscopic ultrasound yields detailed images of the extrahepatic biliary tree, but its value in contributing to the diagnosis of this condition is unknown.

OBJECTIVES

To determine the potential for transduodenal EUS to detect common bile duct wall thickening in PSC.

DESIGN

A prospective, controlled study with retrospective, blinded data analysis.

SETTING

Single tertiary referral center for inflammatory bowel disease and EUS.

PATIENTS

Four groups of patients were assessed with radial endosonography: PSC (n = 9); inflammatory bowel disease (IBD) with abnormal liver blood tests (n = 21); choledocholithiasis (n = 15); and normal controls (n = 50). Measurements were made of the common bile duct diameter and wall thickness.

INTERVENTIONS

Transduodenal radial EUS of the biliary tree.

MAIN OUTCOME MEASUREMENTS

Common bile duct diameter and wall thickness.

RESULTS

The mean diameter (SD) of the common bile duct for the PSC, IBD, choledocholithiasis, and normal control groups measured 8.9 mm (2.8), 5.4 mm (1.7), 7.2 mm (2.2), and 5.0 mm (1.9), respectively (PSC and choledocholithiasis groups compared to the IBD group, P < .05 for a single test of hypothesis, but correction for the multiple testing of data removed this significance; normal control group P < .005). Mean ductal wall thickness (SD) was 2.5 mm (0.8) for the PSC group, 0.7 mm (0.4) for the IBD group, 0.8 mm (0.4) for the choledocholithiasis group, and 0.8 mm (0.4) for the normal control group, respectively (PSC group compared to the other 3 groups, P < .005).

LIMITATIONS

Assessment of intrahepatic PSC is problematic.

CONCLUSION

Thickening (>1.5 mm) of the common bile duct wall is seen in patients with PSC but not in those with apparently uncomplicated IBD or choledocholithiasis. The results of this study suggest that standard endosonography contributes to the imaging and potentially to the diagnosis of PSC.

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.

Endoscopic ultrasound and fine-needle aspiration of unexplained bile duct strictures

OBJECTIVES

The aim of this study was to assess the utility of endoscopic ultrasound (EUS) with fine-needle aspiration (FNA) in patients with unexplained common bile duct strictures after endoscopic retrograde cholangiopancreatography (ERCP) and intraductal tissue sampling.

METHODS

Records were reviewed for all subjects undergoing EUS for evaluation of unexplained bile duct strictures at our institution. 40 subjects had either a final histologic diagnosis (24) or no evidence of malignancy after at least 1 yr of follow-up (16).

RESULTS

The finding of a pancreatic head mass and/or an irregular bile duct wall had sensitivity for malignancy of 88%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 84%. Bile duct wall thickness >/=3 mm had a sensitivity for malignancy of 79%, specificity of 79%, positive predictive value of 73%, and negative predictive value of 80%. Sensitivity of EUS FNA for malignancy was 47% with specificity 100%, positive predictive value 100%, and negative predictive value 50%.

CONCLUSIONS

Sonographic features may be more sensitive than EUS FNA for diagnosis of unexplained bile duct strictures and include presence of a pancreatic mass, an irregular bile duct wall, or bile duct wall thickness > 3 mm. EUS FNA cytology is specific but insensitive for diagnosis. EUS improves the diagnosis of otherwise unexplained bile duct strictures.

[Diagnosis of biliary tract carcinoma]

There are several diagnostic tools available in the diagnosis of bile duct cancer. Tumors of the middle and distal part of the extrahepatic bile duct are accessible to endosonography. Endoscopic retrograde cholangiopancreatography (ERC) and percutaneous transhepatic cholangiography (PTC) are the most invasive procedures for diagnosis of bile duct cancer. However, they offer the opportunity to obtain material for cytological or histological investigation. Moreover, bile flow can be assured by inserting endoprostheses during the procedure. Cholangioscopy and/or intraductal ultrasonography can be performed during ERC. They confer to the diagnosis of a malignant bile duct tumor and are the most accurate methods to diagnose the extent of longitudinal spread. Magnetic resonance imaging-cholangiography is an efficient diagnostic procedure which should be used first, if the bile duct tumor is located in the hilar region.

Innovative methods of biliary tract diagnosis: intraductal ultrasound and tissue acquisition

Tissue can be acquired from the bile and pancreatic duct with either brush cytology or biopsy forceps, often without the need for sphincterotomy. Although the diagnosis of malignancy with these sampling techniques is often specific, the sensitivity is limited, and a wide range of diagnostic accuracies has been reported. A combination of biopsy and brush cytology along with some newer techniques in the development stage may increase the sensitivity. Intraductal ultrasound is a newer technique offers the endoscopist the ability to image the bile and pancreatic duct wall, adjacent organs, and vascular structures with a high degree of detail. This visualization can be accomplished during the course of an ERCP or percutaneously under fluoroscopic guidance. Indications for the procedure include detection of choledocholithiasis, differentiation of benign and malignant ductal strictures, pancreaticobiliary tumor staging, and detection of various pancreatic tumors. Continued research into the design of the probes, which could improve durability and extend the depth of penetration, may promote more widespread use of this novel technology.

Evaluation of indeterminate bile duct strictures by intraductal US

BACKGROUND

Cholangiography and tissue sampling (brush cytology, biopsy) are the standard nonsurgical techniques for determining whether a bile duct stricture is benign or malignant. The aim of this study was to determine whether intraductal US is of assistance in distinguishing benign from malignant biliary strictures.

METHODS

A retrospective review was undertaken of 30 patients with indeterminate bile duct strictures who underwent ERCP and tissue sampling from September 1999 to November 2000. A 20 MHz over-the-guidewire intraductal US catheter probe was used during ERCP for further examination of the strictures. Final diagnoses of malignant strictures (18 patients) were confirmed histopathologically; confirmation of benign stricture (12 patients) was based on negative tissue sampling plus extended clinical follow-up.

RESULTS

Based on retrospective blinded review, the diagnosis by ERCP was correct in 67% of patients, by tissue sampling in 68%, by combined ERCP/tissue sampling in 67%, and by intraductal US in 90% (p = 0.04 vs. ERCP/tissue sampling) of cases. No complication of intraductal US or ERCP was recorded.

CONCLUSIONS

Intraductal US is safe and can improve on the ability at ERCP to distinguish benign from malignant biliary strictures.

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.

Intraductal ultrasound in the biliary tract

Although endoscopic ultrasonography (EUS) represents a major advance in endoscopic imaging, endosonography using dedicated echoendoscopes has some serious drawbacks, including the diameter of the echoendoscope (12 to 13 mm), the lack of intraluminal examination of the pancreatobiliary duct system due to the size of the instrument, unsatisfactory image quality and resolution for small lesions, and the need for a second examination separate from the previous routine endoscopy. Recently developed ultrasonographic miniprobes (diameter, about 2 mm; frequency, 12 to 20 MHz) can be passed through the working channel of standard endoscopes to provide high-frequency ultrasound images. These miniprobes may overcome some of the noted drawbacks and add to the safety and convenience of patients. Moreover, in various diseases of the gastrointestinal tract and the pancreatobiliary ductal system, the diagnostic accuracy of miniprobe ultrasonography has been proven to be superior to that of EUS. Miniprobe ultrasonography is a promising tool that adds new capabilities to the armamentarium of gastroenterologic diagnostic assessment.

Multiple bile duct biopsies using a sheath with a side port: usefulness of intraductal sonography

OBJECTIVE

We clarified the number of biopsies required to determine malignancy of the biliary tract on the basis of the type of bile duct tumor.

SUBJECTS AND METHODS

Patients with a biliary tract malignancy (n = 33) and a benign biliary stenosis (n = 3) underwent biopsy via the percutaneous transhepatic route. We performed intraductal sonography using a 20-MHz probe with a 2.0-mm diameter. The sonographic findings were prospectively classified as polypoid, circular, or semicircular. The tip of a long 9-French sheath with a side port was wedged into the stenosis, and six specimens were obtained with a 1.8-mm-diameter forceps with serrated cups.

RESULTS

When cholangiography or intraductal sonography showed a polypoid lesion, the sensitivity of two biopsies was 100% (6/6). When cholangiography showed a stenotic lesion, the sensitivity of nine biopsies (96%, 26/27) was superior to that of two biopsies (74%, 20/27; p < 0.05). When intraductal sonography showed a circular lesion, the sensitivity of three biopsies (100%, 14/14) was superior to that of a single biopsy (64%, 9/14; p < 0.05). When it showed a semicircular lesion, the sensitivity of nine biopsies (92%, 12/13) was superior to that of two biopsies (54%, 7/13; p < 0.05).

CONCLUSION

Bile duct biopsy using a sheath with a side port has a high sensitivity. However, the number of biopsies required depends on the cholangioscopic and intraductal sonographic appearance of the tumor.

Transpapillary intraductal US prior to biliary drainage in the assessment of longitudinal spread of extrahepatic bile duct carcinoma

BACKGROUND

The utility of intraductal US via the transpapillary route prior to biliary drainage in the assessment of longitudinal extension of extrahepatic bile duct carcinoma was investigated.

METHODS

In 19 patients with extrahepatic bile duct carcinoma who underwent surgical resection, an ultrasonic probe (diameter, 2.0 mm; frequency, 20 MHz) was inserted into the bile duct via the transpapillary route prior to biliary drainage. Longitudinal cancer extension along the bile duct was prospectively determined and compared with the histologic findings in the resected specimens.

RESULTS

Results on the hepatic side were as follows: Intraductal US demonstrated more extensive longitudinal cancer spread than cholangiography in 9 of 19 patients with one instance of overdiagnosis. The accuracy of intraductal US in assessing the extent of spread (84%) was superior to that of cholangiography (47%) (p < 0.05). Results on the duodenal side were as follows: In patients with suprapancreatic bile duct cancer (n = 14), intraductal US demonstrated more extensive longitudinal cancer spread than cholangiography in 8 of 14 patients. The accuracy of intraductal US in assessing the extent of the spread (86%) was superior to that of cholangiography (43%) (p < 0.05).

CONCLUSIONS

Transpapillary intraductal US prior to biliary drainage is useful in demonstrating longitudinal extension of bile duct cancer. However, the surgical margins were inaccurate in some patients.

Comparison of intraductal ultrasonography with percutaneous transhepatic cholangioscopy for the identification of residual bile duct stones during lithotripsy

BACKGROUND

An imaging modality that can be used to identity small stones after a biliary lithotripsy is required. Intraductal ultrasonography was evaluated by using percutaneous transhepatic cholangioscopy as the gold standard.

METHODS

Lithotripsy, under percutaneous transhepatic cholangioscopy guidance, was performed in 20 patients. A thin-caliber ultrasonic probe (2.0 mm in diameter and 20 MHz frequency) was inserted into the bile duct through the percutaneous tract after lithotripsy, and residual stones were identified. This was followed by percutaneous transhepatic cholangioscopy.

RESULTS

In the extrahepatic bile ducts, intraductal ultrasonography provided images of all the stones demonstrated on cholangioscopy (n = 11). The sensitivity was superior to that of cholangiography (P < 0.005). However, in the intrahepatic bile ducts, intraductal ultrasonography only visualized the stones located in the cannulated lobe. Extrahepatic stones smaller than 5.0 mm in diameter or in a common hepatic duct larger than 15.0 mm in diameter were missed by cholangiography, but were visualized by the use of intraductal ultrasonography (P < 0.05).

CONCLUSIONS

Intraductal ultrasonography is equivalent to cholangioscopy in the extrahepatic bile ducts. Cholangiography and intraductal ultrasonography should be used in combination to image intrahepatic and extrahepatic stones.

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.

Gastrointestinal miniprobe sonography: the current status

Endoscopic ultrasonography (EUS) represents a major advance in endoscopic imaging. The usefulness and effectiveness of EUS have been established during the past few years. However, endosonography using dedicated echoendoscopes (7.5/12 MHz) has some serious drawbacks, as follows: 1) Combining endoscopy and ultrasonography in one instrument increases the diameter of such echoendoscopes (12-13 mm); 2) Because of the large diameter, complete passage of severe strictures is often not possible and, for examination of the pancreatobiliary duct system, is not feasible at all; 3) Image quality and resolution for small lesions is not always satisfactory; and 4) Conventional endosonography requires a second examination separate from the previous routine endoscopy. Recently developed ultrasonographic miniprobes (diameters about 2 mm; frequencies 12-20 MHz) can be passed through the working channel of standard endoscopes to provide high frequency ultrasound images. These miniprobes might overcome some of the above-mentioned drawbacks and contribute to patients' security and convenience. Moreover, in various diseases of the GI tract and the pancreatobiliary duct system, diagnostic accuracy of miniprobe ultrasonography has been shown to be even superior to that of EUS. In summary, miniprobe ultrasonography seems to be a promising tool in the armamentarium of gastroenterological diagnostics.

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.

EUS compared with CT, magnetic resonance imaging, and angiography and the influence of biliary stenting on staging accuracy of ampullary neoplasms

BACKGROUND

Computerized tomography (CT), magnetic resonance imaging (MRI), and transabdominal ultrasound frequently fail to detect ampullary lesions. Endoscopic ultrasound (EUS) is a sensitive modality for detecting and staging ampullary tumors. Accurate staging may be affected by biliary stenting, which is frequently performed in these patients with obstructive jaundice. The present study assessed the accuracy of ampullary tumor staging with multiple imaging modalities in patients with and those without endobiliary stents.

METHODS

Fifty consecutive patients with ampullary neoplasms from two endosonography centers were preoperatively staged by EUS plus CT (37 patients), MRI (13 patients), or angiography (10 patients) over a 3(1/2) year period. Twenty-five of the 50 patients had a transpapillary endobiliary stent present at the time of endosonographic examination. Accuracy of EUS, CT, MRI, and angiography was assessed with the TNM classification system and compared with surgical-pathologic staging. The influence of an endobiliary stent present at the time of EUS on staging accuracy of EUS was also evaluated.

RESULTS

EUS was more accurate than CT and MRI in the overall assessment of the T stage of ampullary neoplasms (EUS 78%, CT 24%, MRI 46%). No significant difference in N stage accuracy was noted between the three imaging modalities (EUS 68%, CT 59%, MRI 77%). EUS T stage accuracy was reduced from 84% to 72% in the presence of a transpapillary endobiliary stent. This was most prominent in the understaging of T2/T3 carcinomas.

CONCLUSIONS

EUS is superior to CT and MRI in assessing T stage but not N stage of ampullary lesions. The presence of an endobiliary stent at EUS may result in underestimating the need for a Whipple resection because of tumor understaging.

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.

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.

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.