Masahiro Mitake

New technique using intraductal ultrasonography for the diagnosis of diseases of the pancreatobiliary system.

Intraductal ultrasonography (IDUS), a new technique for visualizing arterial structures, operates at an ultrasound frequency of 30 MHz to produce high resolution, cross‐sectional images in real time. The purpose of this study was to provide a basis for interpreting IDUS images in vitro. We also attempted to determine the clinical usefulness of the IDUS system in diagnosing pancreatobiliary diseases in vivo. IDUS echograms of both the bile duct (BD) and main pancreatic duct (MPD) from autopsy specimens of 15 patients demonstrated three distinct layers with a fine reticular pattern in the pancreas in vitro. In clinical cases, the MPD and BD of four patients could be scanned by inserting the IDUS catheter via the major papilla without requiring endoscopic sphincterotomy. We hope that IDUS will become routine in scanning the BD and MPD to achieve early and accurate diagnoses of pancreatobiliary diseases.

Endoscopic ultrasonography in diagnosis of the extent of gallbladder carcinoma.

Endoscopic ultrasonography (EUS) was performed preoperatively in 39 patients with gallbladder carcinoma. Diagnosis of the anatomical extent of gallbladder carcinoma was compared with histologic analysis, and staging accuracy was evaluated according to the TNM classification. Carcinoma considered to be at an early stage with no lymph node metastasis was correctly diagnosed in 87.5%. Differential diagnosis between early and advanced staged tumors was possible in 79.5%. Overall accuracy for depth of tumor invasion (T) was 76.9%. Limitations were due to many stones in the gallbladder and microinfiltration of carcinoma. Assessment of regional lymph node metastasis (N) was at a sensitivity of 81.8% and specificity of 92.9%, for an overall accuracy of 89.7%. We believe endoscopic ultrasonography is useful in the clinical staging of gallbladder carcinoma.

Differential diagnosis of pancreatic diseases with an intraductal ultrasound system

Forty patients with pancreatic diseases (11 cancer, 1 islet cell tumor, 12 mucin-producing tumor, 1 teratoma, and 15 chronic pancreatitis) were studied in vivo with ERP and were also scanned with an intraductal ultrasound (IDUS) probe at a frequency of 30 MHz inserted into the main pancreatic duct. The usefulness of in vivo IDUS was evaluated by comparison of images with the ERP findings. IDUS was of diagnostic value in 18 of the 40 patients; it distinguished between 4 malignant and 6 benign causes of localized stenosis revealed by ERP, provided parenchymal information in 2 cases with only displacement revealed by ERP (1 islet cell tumor and 1 teratoma), and determined the extent of tumor in 6 cases with main-duct-type mucin-producing tumor. Ten of 11 cancer, 4 of 12 mucin-producing tumor, 1 islet cell tumor, and 11 of 15 chronic pancreatitis (previously scanned in vivo), and 2 islet cell tumor (not scanned in vivo), were resected and scanned in vitro. Fifteen normal pancreases from autopsy subjects were also scanned in vitro. The IDUS images were then compared with corresponding histopathological sections from the 15 normal pancreases and 28 post-operative pancreatic specimens. Differential diagnosis of the pancreatic diseases by echo patterns was possible in all cases except those with intraductal papillary adenocarcinoma and adenoma.

Endoscopic ultrasonography in the diagnosis of depth invasion and lymph node metastasis of carcinoma of the papilla of Vater.

To evaluate diagnostic accuracy of endoscopic ultrasonography (EUS) on the extent of carcinoma of the papilla of Vater, 28 patients were preoperatively evaluated using our EUS grading system. EUS was accurate in diagnosing carcinoma infiltration into the duodenal proper muscle layer (100%) and into the pancreas (75%). When compared with postoperative histologic findings, the overall accuracy of EUS in assessing local infiltration was 89.3%. Misdiagnoses occurred in three cases due to microinfiltration of the carcinoma. Lymph node metastasis around the pancreatic head was accurately diagnosed in nine cases; however, mesenteric lymph node metastasis could not be detected in four cases because the tumor was far from the scanning site.

Ultrasonographic angiography in gallbladder diseases

Ultrasonographic (US) angiography was performed by sonographic examination with injection of carbon dioxide microbubbles through a catheter following conventional angiography in 41 patients with various gallbladder diseases. Three enhancement patterns were found; strong enhancement in the lesion from the periphery to the center was noted in patients with adenocarcinoma and benign polyp (type I), irregular partial enhancement at the margins of the lesion in those with adenosquamous carcinoma (type II), and internal regular enhancement in those with chronic cholecystitis, xanthogranulomatous cholecystitis and adenomyomatosis (type III). Pseudopolypoid lesion such as gallbladder debris showed no enhancement. US angiography may be useful in the differential diagnosis of gallbladder diseases, especially to differentiate the wall thickening type of gallbladder carcinoma from chronic cholecystitis or adenomyomatosis, and the pseudopolypoid lesion and fundal type of adenomyomatosis from benign polyp or polypoid-type carcinoma.

Endoscopic ultrasonography in the diagnosis of pancreatic islet cell tumors.

To evaluate the diagnostic value of endoscopic ultrasonography (EUS) in small‐sized pancreatic islet cell tumors, sonograms obtained by extracorporeal ultrasonography (US) and EUS were reviewed. EUS was superior to US in accurately determining localization and tumor delineation. A small‐sized tumor was visualized as a hypoechoic mass with central echogenic portions. Margin was clear, and contour was smooth. Microcysts were seen in four cases, strong echoes in two, and lateral shadowing in four. From these findings, which reflect histopathologic changes in the tumor, we believe EUS with its high‐resolution is useful in preoperative diagnosis of pancreatic islet cell tumors.

New Endoscopic Approach to Diagnosing Pancreatic Diseases Using an Intraductal Ultrasound System

Abstract: We found that pancreatic diseases can be accurately visualized and diagnosed from the main pancreatic duct via the major papilla using an intraductal ultrasound (IDUS) catheter at a frequency of 30 MHz to create a 360 real‐time image. Herein we present the problems and potential future development of the IDUS system in visualizing pancreatic diseases. The clinical application of the IDUS was evaluated in 16 patients with pancreatic diseases (3 with pancreatic cancer, 6 with a mucin‐producing tumor and 7 with chronic pancreatitis). Insertion was successful in all 4 patients (100%) with a wide‐open orifice and in 9 out of 12 patients (75%) with a normal orifice.

The Diagnosis of the Anomalous Connection of Pancreaticobiliary Ducts Without Biliary Dilatation—The Usefulness of US/EUS Serial Examination—

The anomalous connection of the pancreaticobiliary duct (ACPBD) without accompanying dilatation of the bile duct (non‐dilated type of ACPBD) has recently been found to be associated with gallbladder cancer at a rather high rate. We analyzed the diagnostic process of 5 patients with non‐dilated type of ACPBD including 3 asymptomatic cases and reviewed the literature. Symptoms and laboratory data were not useful in detecting this type of lesion. All our patients were checked by ultrasonography for gallbladder lesions which are suggested by: wall thickening, multiple polyps, intramural gall stones, cholecystolithiaisis, and debris. ACT revealed only wall thickening of the gallbladder. An EUS revealed a high rate of ACPBD in addition to the ultrasonographic findings of gallbladder lesions obtained by US. An ERCP was effective in clearly demonstrating ACPBD, but was not so useful for the diagnosis of concomitant gallbladder lesions. Therefore, an US is considered to be a useful means for screening this disease, and EUS is useful as a procedure to follow in order to select patients with or without ACPBD, because EUS can be conducted on an outpatient basis and is highly sensitive in detecting ductal anomalies in ACPBD. Therefore, the US/EUS serial examination is thought to be an effective means for diagnosing this disease.

Aggressive non-Hodgkin's lymphoma after successful eradication of Helicobacter pylori and regression of gastric lymphoma of mucosa-associated lymphoid tissue

Abstract: A 57-year-old woman presented to our clinic with low-grade gastric lymphoma of mucosa-associated lymphoid tissue (stage IE) and Helicobacter pylori infection. She received a 2-week course of omeprazole and clarithromycin, resulting in eradication of H. pylori and histological disappearance of the lymphoma. However, 9 months later (May 1996), multiple mass lesions were found around the pancreas and hepato-duodenal ligament on abdominal computed tomography. Inguinal lymph node biopsy revealed aggressive nodal type B-cell non-Hodgkins lymphoma, diffuse large cell type. She received chemotherapy with cyclophosphamide, adriamycin, vincristine, and prednisolone, but failed to achieve remission and died in December 1996. There was no evidence of recurrent gastric lymphoma. This case emphasizes the importance of performing follow-up examinations to detect other neoplasms in patients with gastric lymphoma of mucosa-associated lymphoid tissue.