Masatsugu Nakajima

Endoscopic sphincterotomy of the ampulla of Vater

Endoscopic sphincterotomy at the papilla of Vater, combining and modifying technics already established for retrograde cannulation and electrosurgical polypectomy, has been successfully performed in 2 patients with removal of stones impacted in the ampulla and proximal common bile duct. The authors caution that further investigation is in order to assure the safety and efficacy of the procedure.

The diagnosis of pancreatic cancer by endoscopic ultrasonography.

Endoscopic ultrasonography was evaluated for detection of tumors of the pancreas. The technique was performed in 42 patients with cancer of the pancreas and 8 patients with nodular fibrosis of chronic pancreatitis. The lesions were clearly identified in all 50 patients, even when the size of the tumor was less than 20 mm in diameter. A tumor of the pancreas was usually visualized as a hypoechoic mass that had a characteristic image depending on the size. Ultrasonographic differentiation of malignant from benign tumors of the pancreas was possible in tumors larger than 30 mm in size but difficult in tumors less than 20 mm in size. Compared with conventional ultrasonography, endoscopic retrograde pancreatography, computed tomography, and angiography, endoscopic ultrasonography had the highest detection rate of tumors of the pancreas, especially in cases of small tumors under 20 mm in size. In cancer of the pancreas, endoscopic ultrasonography also proved to be valuable for the detection of vascular invasion.

Clinical evaluation of a newly developed single-balloon enteroscope

BACKGROUND Double-balloon enteroscopy (DBE) is a useful and epoch-making technique for small-bowel diseases. The single-balloon enteroscope (SBE) is a new instrument introduced by Olympus. OBJECTIVE To evaluate a prototype of the SBE. DESIGN A prospective case series. SETTING Kyoto Second Red Cross Hospital, between April 2006 and July 2007. PATIENTS We used the SBE system to perform 37 enteroscopic examinations on 27 patients, including 22 oral and 15 anal approaches. MAIN OUTCOME MEASUREMENTS The rate of whole small-bowel visualization, mean time necessary for the investigation, discovery rate of lesions, and complications. RESULTS We observed the entire small intestine in 1 of 8 cases (12.5%) that we examined. The mean (+/-SD) time necessary for the oral approach was 83 +/- 38 minutes and that for the anal approach was 90 +/- 32 minutes. The preparation time was less than 5 minutes in both approaches. Small-intestinal lesions were detected in 11 of the 27 patients (40.7%). Perforation occurred in one case as a complication, but the injury healed without surgical intervention. LIMITATION This was a single-center study. CONCLUSIONS Use of the SBE system in the endoscopic study of the small intestine makes it possible to observe the entire small intestine and to diagnose lesions; thus, the SBE system is a useful instrument for small-bowel diseases. However, the rate of whole small-bowel visualization was inferior to the DBE system.

The diagnosis of submucosal tumors of the stomach by endoscopic ultrasonography

The clinical value of endoscopic ultrasonography (EUS) in the diagnosis of submucosal tumors (SMTs) of the stomach was examined. We used echo endoscopes with a 7.5 or 10.0 MHz radial-scan transducer made by Olympus Co. Ltd. EUS was carried out on 80 patients with SMTs of the stomach including 54 cases confirmed histologically (24 cases of leiomyoma, 3 of leiomyosarcoma, 12 of cysts, 7 of aberrant pancreas, 4 of lipoma, 2 of carcinoid, and 3 of other diseases). Fifty-nine patients with extraluminal compression were detected by endoscopy and/or x-ray examination. We examined the effectiveness of EUS based on our analysis of the gastrointestinal tract wall seen in the EUS image as a five-layered structure corresponding with that of the histological layers. As a result, SMTs and extragastric compression were easily distinguishable in the EUS images of the lesions. The size, location, and origin of the SMTs could be detected. From the location of the SMT in the five-layered structure seen in the EUS image we could predict its histological nature. Thus, EUS was a most valuable method not only in the diagnosis of intramural and extramural SMTs but also in the detection of extragastric compressive lesions and organs.

Evaluation of endoscopic ultrasonography in the pre-operative staging of carcinoma of the ampulla of Vater and common bile duct.

Endoscopic ultrasonography (EUS) was performed in 23 patients with carcinoma of the ampulla of Vater (ampulla) and in 16 patients with common bile duct (CBD) carcinoma. These patients all underwent surgery. The layered structures of the duodenum, ampulla, and CBD, and the pancreas, portal vein, and regional lymph nodes were clearly identified by EUS using a transduodenal approach. With this technique, ampullary carcinoma appeared as a hypoechoic mass in 22 of 23 patients, and the 1 remaining cancer was not detected because of its small size. Carcinoma of the CBD also appeared as a hypoechoic mass in 12 of 16 patients. However, the remaining four appeared as hyperechoic masses. For these tumors, EUS had a high tumor detection rate (96 to 100%). In this regard, EUS was comparable to ERCP and was better than ultrasonography (US), CT, and angiography. Using EUS, we were also able to stage the extent of these tumors according to the involvement of the duodenal or CBD walls, invasion of the pancreas and portal vein, and spread to regional lymph nodes. The accuracy rates of cancer extent by EUS were 78% for ampullary carcinoma and 81% for CBD carcinoma when compared with surgical findings. We conclude that EUS is a valuable method for the detection and staging of tumors of the ampulla and CBD.

Diagnosis of submucosal lesions of the upper gastrointestinal tract by endoscopic ultrasonography

The use of endoscopic ultrasonography (EUS) in the diagnosis of submucosal upper gastrointestinal tract lesions was examined in 308 patients. Two-hundred ten submucosal tumors, 89 cases of esophagogastric varices, and 9 cases of non-Hodgkins lymphoma were found. EUS images were interpreted based upon a five-layer EUS structure of the normal gastrointestinal wall. A characteristic EUS image was seen with leiomyoma, cysts, lipoma, and varices. EUS had an accuracy of 80% in staging nine cases of lymphoma. EUS is a valuable technique for the evaluation and diagnosis of submucosal upper gastrointestinal tract lesions.

Clinical significance of cathepsin E in pancreatic juice in the diagnosis of pancreatic ductal adenocarcinoma.

Background: It has been reported that cathepsin E (CTSE) is a non‐secretory and intracellular aspartic proteinase found in the superficial epithelial cells of the stomach and that it is also expressed in pancreatic ductal adenocarcinoma. We evaluated the diagnostic value of CTSE in the pancreatic juice in the diagnosis of pancreatic ductal adenocarcinoma compared with that of CA19–9, carcinoembryonic antigen (CEA) and K‐ras mutations.

Endoscopic Ultrasonography in the Diagnosis of Submucosal Tumor of the Upper Digestive Tract

The clinical value of endoscopic ultrasonography (EUS) in the diagnosis of submucosal tumors (SMT) in the upper digestive tract was examined. EUS was performed in 83 patients with SMT or submucosal compressions by extracanal organs or lesions. The 50 cases of SMT and 33 cases of extracanal compression could be diagnosed accurately. All SMT were easily detected, even if they were smaller than 5 mm in diameter. EUS visualized in which of the five layers of the digestive tract wall the submucosal tumor was located and depicted the size of the tumor accurately as confirmed by examination of the resected material. Leiomyoma and leiomyosarcoma originating in the mucosal muscle layer and the proper muscle layer were difficult to distinguish by EUS. The submucosal tumors in the submucosal layer, such as cysts, an aberrant pancreas, fibromas, and lipomas could be diagnosed by the analysis of echogenicity and echo-pattern of the tumor ultrasonograms. EUS was considered to be the most useful method among the conventional body imaging techniques to visualize submucosal tumors.

The use of pancreatoscopy in the diagnosis of intraductal papillary mucinous tumor lesions of the pancreas.

The diagnosis of intraductal papillary mucinous tumor (IPMT) can be performed under the direct visualization of peroral pancreatoscopy (PPS), although the visible field with PPS is limited and endoscopic accessories cannot be easily applied. PPS is useful in cases with IPMT not only for the main duct lesions but also for some of the branch lesions that can be shown through the dilated branch duct. PPS is useful for diagnosing IPMT because histologic diagnosis is possible from biopsy materials obtained by PPS or with radiograph guidance. Histologic findings can be suspected from the appearance and degree of the protrusion of the lesions in the cystic lesion or in the main duct. Thirty patients with IPMT were resected and confirmed histologically. Among them, 26 cases were examined by PPS. Detection rates of the 12 cases with polypoid tumor greater than 3 mm were 67% by PPS, 92% by endoscopic ultrasonography, and 100% by intraductal ultrasonography. Among the 6 cases of adenocarcinoma, 4 cases showed a tumor mass greater than 10 mm.

Direct endoscopic visualization of the bile and pancreatic duct systems by peroral cholangiopancreatoscopy (PCPS)

Peroral cholangiopancreatoscopy (PCPS), a new concept in gastrointestinal endoscopy, has been developed for direct examination of the bile and pancreatic duct systems. The procedure was successfully accomplished in 42 of 50 patients with no complications. Stones and tumors of the ducts were directly inspected by this new technique. There are still certain technical limitations in the use of our prototype instruments. When the improved instruments are available in the near future, PCPS promises to be one of the most reliable tools in the diagnosis and management of biliary and pancreatic diseases.