Usefulness of Intraductal Ultrasonography in the Diagnosis of Cholangiocarcinoma and IgG4-Related Sclerosing Cholangitis

The technique of intraductal ultrasonography (IDUS) of the bile duct with a thin-caliber probe and a ropeway system has provided excellent images of the bile duct and periductal structures and is an easy transpapillary approach. In addition, once the guide wire is inserted into the bile duct, IDUS and transpapillary biopsy after endoscopic retrograde cholangiopancreatography can be performed in a single session. Here, we review the usefulness of IDUS in the diagnosis of cholangiocarcinoma and IgG4-related sclerosing cholangitis.

Endoscopic treatment for biliary stricture secondary to chronic pancreatitis

The causes of benign biliary stricture include chronic pancreatitis, primary/immunoglobulin G4-related sclerosing cholangitis and complications of surgical procedures. Biliary stricture due to fibrosis as a result of inflammation is sometimes encountered in patients with chronic pancreatitis. Frey's procedure, which can provide pancreatic duct drainage with decompression of biliary stricture, can be an initial treatment for chronic pancreatitis with pancreatic and bile duct strictures with upstream dilation. When patients are high-risk surgical candidates or hesitate to undergo surgery, endoscopic treatment appears to be a potential second-line therapy. Placement of multiple plastic stents is currently considered to be the best choice as endoscopic treatment for biliary stricture due to chronic pancreatitis. Temporary placement with a fully covered metal stent has become an attractive option due to the lesser number of endoscopic retrograde cholangiopancreatography (ERCP) sessions and its large diameter. Further clinical trials comparing multiple placement of plastic stents with placement of a covered metal stent for biliary stricture secondary to chronic pancreatitis are awaited.

Intraductal ultrasonography in the diagnosis of bile duct stones: when and whom?

BACKGROUND AND AIM

Biliary intraductal ultrasonography (IDUS) is highly sensitive in visualizing bile duct stones (BDS). Indications for IDUS, however, in cases of suspected BDS have not yet been established. The aim of the present study was to elucidate adequate indications for IDUS in cases that undergo endoscopic retrograde cholangiopancreatography (ERCP) due to suspected BDS.

METHODS

A total of 213 patients who were suspected of having BDS were included in this retrospective study. The patients were divided into two groups: Group A in which BDS was visualized by ERCP; and Group B in which BDS was demonstrated only by IDUS. Comparison between the groups was carried out.

RESULTS

ERCP successfully visualized BDS in 166 patients. Forty-seven patients underwent IDUS, which revealed BDS and biliary sludge in 12 and eight patients, respectively. The diameter of the largest stone was 13 ± 6 mm in Group A and 5 ± 1 mm in Group B (P < 0.001). The sensitivity, specificity, and accuracy of ERCP in the diagnosis of BDS were 93%, 100%, and 94%, respectively. The sensitivity was influenced by the size of BDS: 100% in cases of stones ≥ 8 mm in size, but 74% in those with stones < 8 mm. In cases with stones < 8 mm, the sensitivity was significantly affected by the bile duct diameter (≥ 12 mm vs < 12 mm, P < 0.05).

CONCLUSION

  When ERCP fails to visualize stones in patients with suspected BDS, IDUS is recommended, especially in those with a bile duct ≥ 12 mm in diameter.

Lateral spread along the main pancreatic duct in branch-duct intraductal papillary-mucinous neoplasms of the pancreas: usefulness of intraductal ultrasonography for its evaluation

BACKGROUND

Intraductal papillary mucinous neoplasms (IPMN) of the pancreas tend to spread intraepithelially along the pancreatic duct wall. We evaluated histopathological intraductal lateral spread (LS) along the main pancreatic duct (MPD) from branch-duct IPMN and investigated the usefulness of intraductal ultrasonography (IDUS) for its preoperative diagnosis.

PATIENTS AND METHODS

Twenty-four patients with branch-duct IPMN who had undergone preoperative IDUS and surgery were reviewed clinicopathologically. The prevalence and histological length of LS along the MPD from branch-duct IPMN, characteristics of the patients with LS, and efficacy of LS assessment by IDUS were examined.

RESULTS

LS along the MPD was observed in 54% of the subjects. In the group of patients with LS, its mean length was 25.2±16.8mm (5-50mm) and the diameter of the MPD was 6mm or greater. Of the patients with LS, those in whom the length of LS along the MPD was longer than the diameter of the cystically dilated branch accounted for 30%. The diameter of the MPD in the group with LS was significantly greater than that in the group without LS (P=0.03). The sensitivity, specificity, and overall accuracy of IDUS in the detection of LS were 92%, 91%, and 92%, respectively.

CONCLUSION

LS along the MPD was detected in about half of the resected cases of branch-duct IPMN. Preoperative transpapillary IDUS may be beneficial for the determination of the resection line, especially in those branch-duct IPMN patients in whom the MPD is 6 mm or greater in diameter.

Differential diagnosis and treatment of biliary strictures

Biliary tract strictures present both diagnostic and therapeutic challenges to clinicians. Advances in imaging and endoscopic techniques have improved our ability to differentiate between benign and malignant lesions. Intraductal ultrasonography (IDUS), using an endoscopic approach, has the potential to aid in separating benign and malignant biliary lesions. In a series of 93 patients, a majority of whom had cancer, we found that IDUS had a sensitivity and specificity of 89.7% and 84%, respectively, for diagnosing biliary strictures. However, benign strictures associated with untreated autoimmune pancreatitis and/or the intrapancreatic portion of the distal common bile duct could not be easily distinguished from malignant strictures. Direct visualization of biliary mucosa using a percutaneous transhepatic endoscopic approach also helps separate benign from malignant biliary strictures. Further, the ability to obtain multiple directed biopsies using a percutaneous approach also increases diagnostic accuracy. A final advantage of the percutaneous approach is that once a suitable sized tract has been established, biliary strictures and stents can be placed. IDUS and percutaneous biliary endoscopy are promising new modalities for the diagnosis and treatment of biliary strictures.

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.

Ultrasonographic findings and natural history of intraductal papillary-mucinous neoplasms of the pancreas

It is clear that the prevalence of malignancy is high in the main-duct type of intraductal papillary-mucinous neoplasm (IPMN). Branch-duct IPMNs include several histologic conditions such as carcinoma, adenoma, and hyperplasia. Intraductal papillary adenocarcinoma and papillary adenoma are characterized by papillary protrusions and thick septum-like structures in dilated ducts as delineated by ultrasonography. A solid mass showing a mixedecho pattern in the pancreatic parenchyma is a characteristic finding of invasive types of IPMN. The international guidelines for the management of branch-duct IPMNs suggest that the appearance of symptoms attributable to the cyst, the presence of intramural nodules, a cyst size greater than 30 mm, and dilation of the main pancreatic duct (>6 mm) are indications for resection. Based on the relationship between the height of a papillary protrusion and the diameter of a cystic dilated branch as well as on histological findings, branch-duct IPMNs with papillary protrusions more than 10 mm in height as shown by imaging should be resected, and it is not adequate to differentiate carcinoma from other lesions based on the diameter of cystic branches alone. A follow-up study on branch-duct IPMNs revealed that most papillary protrusions showed a slow increase in size or development of lateral spread, and that there was no development of cancer with stromal invasion during an average follow-up of 46 months. Therefore, the presence of intramural nodules alone should not be an indication for surgery. Also, patients without papillary protrusions or thick septum-like structures are not immediate candidates for surgery. Invasive adenocarcinoma can develop at a pancreatic site different from the area of interest showing cystic changes, with such invasion possibly being multicentric. Therefore, in patients with branch-duct IPMNs, attention should be paid to the entire pancreas when performing follow-up examinations.

Endoscopic management of biliary malignancies

The current status of endoscopic diagnosis and treatment of biliary malignancies is discussed. Three ways are now available to approach the bile duct endoscopically. Endoscopic diagnostic modalities are quite useful for the assessment of local changes because of their high spatial resolution and ability in tissue and bile acquisition for histologic, cytologic, and molecular biologic evaluations. Endoscopic biliary drainage is less invasive and beneficial for patients with obstructive jaundice compared with surgical or percutaneous transhepatic drainage. Continuous evolution should expand its indications.

Preoperative evaluation of ampullary neoplasm with EUS and transpapillary intraductal US: a prospective and histopathologically controlled study

BACKGROUND

Endoscopic papillectomy is performed in selected patients with ampullary neoplasm, and, thus, accurate preoperative tumor staging is indispensable for its application.

DESIGN

Prospective and histopathologically controlled study.

SETTING

Single center.

PATIENTS AND INTERVENTIONS

EUS and transpapillary intraductal US (IDUS) were performed in 40 patients with ampullary neoplasm before surgery (n = 30) or endoscopic papillectomy (n = 10). Ductal infiltration by a tumor into the bile duct (BD) or the pancreatic duct (PD) was also evaluated. The indication for endoscopic papillectomy was determined by findings obtained by EUS and IDUS. These findings were compared with histologic features of the resected specimens.

MAIN OUTCOME MEASUREMENTS AND RESULTS

Thirty-three patients had adenocarcinoma (14 pT1, 11 pT2, 8 pT3-4) and 7 had adenoma. Tumor depiction by EUS and IDUS was achieved in 95% and 100% of the patients, respectively. The diagnostic accuracy of EUS and IDUS in T staging was 62% and 86% in adenoma and pT1, 45% and 64% in pT2, and 88% and 75% in pT3-4, respectively. The overall accuracy by EUS and IDUS in T staging was 63% and 78%, respectively (P = .14). In 10 patients who underwent endoscopic papillectomy, the accuracy of IDUS in T staging with EUS and IDUS was 80% and 100%, respectively. Ductal infiltration into the BD and the PD was correctly assessed in 88% and 90% by EUS and in both BD and the PD in 90% by IDUS, respectively. Ductal infiltration was correctly diagnosed by EUS and IDUS in all patients who had a papillectomy.

CONCLUSION

Although IDUS had a tendency of overestimation in tumor staging for ampullary neoplasm, it can provide useful information for making therapeutic decisions, especially in cases appropriate for endoscopic papillectomy.

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.

Endoscopic approach to early diagnosis of pancreatic cancer

Since its development, endoscopic retrograde cholangiopancreatography (ERCP) has been playing a major role in the diagnosis of pancreatic diseases. The recent development of magnetic resonance cholangiopancreatography has accelerated the shift in the role of ERCP toward more therapy-oriented applications. In the diagnosis and treatment of curable pancreatic cancer, however, ERCP remains the mainstay of imaging modalities. ERCP is not simply a method with which to obtain x-ray images of the pancreatic duct. Collection of pure pancreatic juice, transpapillary biopsy/brush cytology of the pancreatic duct, intraductal ultrasonography, and peroral pancreatoscopy are all performed based on the ERCP technique. Endoscopic ultrasonography (EUS) has a high spatial resolution and provides tomographic images of the pancreas and its neighboring organs. EUS is now widely used in evaluation of the local extent of pancreatic cancer and the differential diagnosis of cystic lesions of the pancreas. EUS-guided fine needle aspiration biopsy/cytology is performed to obtain a histologic diagnosis before beginning chemotherapy. Although the number of pancreatic cancer patients who are candidates for surgery is limited at present, there is an increasing need for ERCP-based techniques in both the diagnosis and treatment of pancreatic neoplasms.

Diagnosis of common bile duct calculi with intraductal ultrasonography during endoscopic biliary cannulation

BACKGROUND

Choledocholithiasis can be difficult to diagnose, even with direct cholangiography. We examined the role of biliary intraductal ultrasonography in detecting common bile duct stones that had been overlooked during endoscopic retrograde cholangiopancreatography.

METHODS

Eighty consecutive patients who underwent endoscopic retrograde cholangiography for suspected choledocholithiasis with negative results were evaluated with intraductal ultrasonography (20 MHz) for the presence of biliary concrements. The diagnostic criterion for stones was a strong-echo structure with acoustic shadowing. Materials of low amplitude echoes without acoustic shadowing were considered sludge.

RESULTS

Intrabile duct scanning was successful in all patients. Of the 80 patients, 20 (25%) had ultrasonic evidence of common bile duct stones. The stones measured 5 mm or less on ultrasound and their presence was confirmed macroscopically during endoscopic (17 patients) or laparoscopic (three patients) bile duct clearance. Another 37 patients (46%) had biliary sludge alone and have been followed up uneventfully.

CONCLUSIONS

Biliary intraductal ultrasonography may become a useful adjunct to establish the diagnosis of occult bile duct concrements and a guide to appropriate therapeutic selection during endoscopic biliary cannulation.

Pancreas: imaging diagnosis with color/power Doppler ultrasonography, endoscopic ultrasonography, and intraductal ultrasonography

Recent advances of ultrasound imaging have made possible to depict various diseases and conditions of the pancreas. Color/power Doppler ultrasonography, endoscopic ultrasonography, and intraductal ultrasonography are feasible to show vascular abnormalities, differentiate the solid and cystic tumors, decide tumor extent, and help to perform interventional treatments of the pancreatic diseases. Those techniques will contribute to the more precise and easier diagnosis and to prompt decision of the treatments of the pancreatic disorders. Radiologists should recognize the diagnostic feasibility and limitations of those techniques in order to avoid unnecessary examinations on the patients, and obtain precise diagnostic images.