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Dive into the research topics where Naoki Okano is active.

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Featured researches published by Naoki Okano.


Clinical Gastroenterology and Hepatology | 2010

Diagnostic Peroral Video Cholangioscopy Is an Accurate Diagnostic Tool for Patients With Bile Duct Lesions

Takao Itoi; Manabu Osanai; Yoshinori Igarashi; Kiyohito Tanaka; Mitsuhiro Kida; Hiroyuki Maguchi; Kenjiro Yasuda; Naoki Okano; Hiroshi Imaizumi; Tomohisa Yokoyama; Fumihide Itokawa

BACKGROUND & AIMS We evaluated the diagnostic ability of a newly developed peroral video cholangioscopy (PVCS) in patients with pancreaticobiliary disorders. METHODS We retrospectively evaluated data from 144 patients with pancreaticobiliary disorders, collected from 5 tertiary referral centers. Endoscopic sphincterotomy (EST) or endoscopic papillary balloon dilation (EPBD) was performed before PVCS. We performed 2 types of PVCS, using a conventional therapeutic duodenoscope. If tissue samples were needed, cholangioscopy-assisted biopsy or fluoroscopy-guided biopsy was performed. RESULTS PVCS was advanced into the bile duct in all cases after patients received EST (n = 134 cases), EPBD (n = 2), a combination of EST and EPBD (n = 1), or without treatment of the major papilla (n = 7). Biopsy samples were collected successfully from 112 of 120 cases in which endoscopists considered tissue sampling necessary. Endoscopic retrograde cholangiopancreatography (ERCP)/biopsy correctly identified 83 of 96 malignant lesions and 19 of 24 benign lesions (accuracy = 85.0%; sensitivity = 86.5%; specificity = 79.2%; positive predictive value = 94.3%; negative predictive value = 59.4%). Endoscopic retrograde cholangiopancreatography (ERCP)/biopsy plus PVCS correctly identified 95 of 96 malignant lesions and 23 of 24 benign lesions (accuracy = 98.3%; sensitivity = 99.0%; specificity = 95.8%; positive predictive value = 99.0%; negative predictive value = 95.8%). Procedure-related complications included pancreatitis (4 cases, 2.8%) and cholangitis (6 cases, 4.3%). CONCLUSIONS PVCS is an accurate diagnostic tool for patients with pancreaticobiliary disorders; resolution was well-defined when combined with biopsy analysis. Prospective multicenter clinical trials should evaluate the clinical utility of PVCS in diagnosis of biliary tract diseases.


Endoscopy | 2013

Peroral video cholangioscopy to evaluate indeterminate bile duct lesions and preoperative mucosal cancerous extension: a prospective multicenter study.

Manabu Osanai; Takao Itoi; Yoshinori Igarashi; K. Tanaka; Mitsuhiro Kida; Hiroyuki Maguchi; K. Yasuda; Naoki Okano; Hiroshi Imaizumi; Fumihide Itokawa

BACKGROUND AND STUDY AIMS Despite the development of peroral video cholangioscopy (PVCS), no prospective multicenter studies have been undertaken to investigate the diagnostic accuracy of PVCS in biliary tract diseases. Therefore, the aim of this study was to clarify the accuracy of PVCS in evaluating biliary tract lesions. PATIENTS AND METHODS This study was a prospective multicenter study at five tertiary referral centers in Japan and included 87 eligible patients with biliary tract diseases who underwent PVCS. The study evaluated the ability of PVCS to diagnose indeterminate biliary tract diseases, detect mucosal cancerous extension preoperatively in extrahepatic bile duct cancers, and predict adverse events. RESULTS The use of PVCS appearance alone correctly distinguished benign from malignant indeterminate biliary lesions in 92.1 % of patients whereas biopsy alone was accurate in 85.7 %. In extrahepatic bile duct cancer, mucosal cancer extended histologically at least 20 mm in 34.7 % (17/49) of patients. The accuracy rate of PVCS to evaluate the presence or absence of mucosal cancerous extension by endoscopic retrograde cholangiography (ERC) alone, ERC with PVCS, and ERC with PVCS + biopsy were 73.5 %, 83.7 %, and 92.9 %, respectively. Adverse events were seen in 6.9 % of PVCS patients, but no serious complications were observed. CONCLUSION PVCS enhanced the accurate diagnosis of biliary tract lesions by providing excellent resolution in combination with biopsy.


Digestive Endoscopy | 2010

ENDOSCOPIC DIAGNOSIS OF INTRADUCTAL PAPILLARY‐MUCINOUS NEOPLASM OF THE PANCREAS BY MEANS OF PERORAL PANCREATOSCOPY USING A SMALL‐DIAMETER VIDEOSCOPE AND NARROW‐BAND IMAGING

Tomihiro Miura; Yoshinori Igarashi; Naoki Okano; Kazumasa Miki; Yoichiro Okubo

Background:  Intraductal papillary‐mucinous neoplasm (IPMN) is an intraductal tumor in which the mucin‐producing epithelium shows proliferated papillary and a wide variety of pathological changes ranging from hyperplasia to adenocarcinoma. Therefore, it is important to determine whether an IPMN is benign or malignant. In the present study of patients with IPMN, the protrusion was observed by a peroral pancreatoscopy (PPS) using a small‐diameter videoscope and narrow‐band imaging (NBI). We carried out the differential diagnosis of benign lesion to malignant lesion.


Digestive Endoscopy | 2005

PERORAL CHOLANGIOSCOPY USING A NEW THINNER VIDEOSCOPE (CHF‐B260)

Yoshinori Igarashi; Naoki Okano; Daisuke Satou; Tomihiro Miura; Kazumasa Miki

The CHF‐B260 videoscope has a 3.4 mm outer diameter, 1.2 mm forceps channel, and two‐way angulations function (70° up and 70° down). Peroral cholangioscopy (POCS) was performed using the CHF‐B260 in 13 patients who were admitted to our hospital between October 2002 and June 2004. The CHF‐B260 was successfully inserted into the bile duct in all cases. Clear images were obtained in 11 patients. Endoscopic images for two cases of malignant stricture due to metastasis of colon cancer and gallbladder cancer were not clear because of bleeding from the tumors. POCS was performed safely in all patients without any complications. POCS with the CHF‐B260 was very useful for the diagnosis of biliary disorders. If the outer diameter and biopsy channel of CHF‐B260 are improved, POCS will become even more effective for the diagnosis of biliary disorder.


Digestive Endoscopy | 2009

EFFECTIVENESS OF PERORAL CHOLANGIOSCOPY AND NARROW BAND IMAGING FOR ENDOSCOPICALLY DIAGNOSING THE BILE DUCT CANCER

Yoshinori Igarashi; Naoki Okano; Ken Ito; Takuya Suzuki; Takahiko Mimura

CHF‐B260 has thinner diameters, and the quality of the endoscopic images has improved. Recently, narrow band imaging (NBI) system has been developed for high‐contrast observation of mucosal structures and vascular patterns. It is available to diagnose for the bile duct cancer endoscopically and it is useful for desciding of surgical margin before operation.


Case Reports in Gastroenterology | 2013

Severe Acute Pancreatitis with Complicating Colonic Fistula Successfully Closed Using the Over-the-Scope Clip System

Ken Ito; Yoshinori Igarashi; Takahiko Mimura; Yui Kishimoto; Itaru Kamata; Shunsuke Kobayashi; Kensuke Yoshimoto; Naoki Okano

A 44-year-old man presenting to our hospital emergency room with abdominal pain was hospitalized for hyperlipidemic acute pancreatitis. A pig-tail catheter was placed percutaneously to drain an abscess on day 22. Although the abscess improved gradually and good clinical progress was seen, pancreatic duct disruption was strongly suspected and endoscopic retrograde cholangiopancreatography was performed on day 90. An endoscopic nasopancreatic drainage tube was placed, but even with concurrent use of a somatostatin analogue, treatment was ineffective. Surgical treatment was elected, but was subsequently postponed as the abscess culture was positive for extended-spectrum β-lactamase-producing Escherichia coli and methicillin-resistant Staphylococcus aureus. Drainage tubography showed a small fistula of the colon at the splenic flexure on day 140. Colonoscopy was performed on day 148. After indigo carmine had been injected, a fistula into the splenic flexure of the colon showed blue staining. The over-the-scope clip (OTSC) system was used to seal the fistula and complete closure was shown. A liquid diet was started on day 159 and was smoothly upgraded to a full diet. Following removal of the pancreatic stent on day 180, drainage volume immediately decreased and the percutaneous drain was removed. On day 189, computed tomography showed no exacerbation of the abscess and the patient was discharged on day 194. This case of colonic fistula caused by severe acute pancreatitis was successfully treated using the OTSC system, avoiding the need for an open procedure.


BioMed Research International | 2014

Efficacy of Combined Endoscopic Lithotomy and Extracorporeal Shock Wave Lithotripsy, and Additional Electrohydraulic Lithotripsy Using the SpyGlass Direct Visualization System or X-Ray Guided EHL as Needed, for Pancreatic Lithiasis

Ken Ito; Yoshinori Igarashi; Naoki Okano; Takahiko Mimura; Yui Kishimoto; Seiichi Hara; Kensuke Takuma

Introduction. To evaluate the efficacy of combined endoscopic lithotomy and extracorporeal shock wave lithotripsy (ESWL), and additional electrohydraulic lithotripsy (EHL) as needed, for the treatment of pancreatic duct stones, we retrospectively evaluated 98 patients with chronic pancreatitis and pancreatic lithiasis. Methods. For the management of main pancreatic duct (MPD) stones in 98 patients, we performed combined endoscopic treatment (ET)/ESWL therapy as the first treatment option. When combined ET/ESWL was unsuccessful, EHL with the SpyGlass Direct Visualization system or X-ray guided EHL was performed. Outpatient ESWL was reserved as one of the final treatment options. Results. Fragmentation was successful in 80 (81.6%) patients as follows: combined ET/ESWL: 67 cases; SpyGlass EHL: 4 cases; X-ray guided EHL: 3 cases; and outpatient ESWL: 6 cases. Successful outcome was obtained by combined ET/ESWL in 67 of the 98 patients (74.5%), by EHL in 7 of 14 patients (7.1%), and by outpatient ESWL in 6 of 6 patients (6.1%). Negotiating the guidewire through a severe MPD stricture was significantly associated with a higher rate of stone fragmentation (P = 0.0003). Conclusions. In cases where combined ET/ESWL was not successful for stone clearance, EHL using the SpyGlass system or X-ray guided EHL was effective in cases where the guidewire could be negotiated through the MPD stricture and it increased the fragmentation rate.


Digestive Endoscopy | 2012

CASE OF IMMUNOGLOBULIN G4-RELATED CHOLANGITIS ACCOMPANYING AUTOIMMUNE PANCREATITIS: DIAGNOSIS BY PERORAL CHOLANGIOSCOPY AND TREATMENT BY ENDOSCOPIC BILIARY STENTING

Naoki Okano; Yoshinori Igarashi; Yui Kishimoto; Ken Ito; Daisuke Sasai

Recently, the progress of endoscopy has made it possible to evaluate bile duct mucosa by peroral cholangioscopy. Herein, we report a case of immunoglobulin G4‐related sclerosing cholangitis accompanying autoimmune pancreatitis in a patient who improved with treatment by steroid therapy and endoscopic biliary stenting, and observed the bile duct mucosa by peroral cholangioscopy before and after treatment.


Digestive Endoscopy | 2007

ENDOSCOPIC OBSERVATION OF MUCOSAL SPREAD LESION OF CHOLANGIOCARCINOMA USING PERORAL CHOLANGIOSCOPY WITH NARROW BAND IMAGING

Yoshinori Igarashi; Naoki Okano; Ken Ito; Takahiko Mimura; Kazumasa Miki

A 69‐year‐old man was admitted to Toho University Omori Medical Center complaining of icterus. Abdominal computed tomography, magnetic resonance cholangiopancreatography and endoscopic retrograde cholangiopancreatography were suspicious of cholangioma of inferior bile duct. Peroral cholangioscopy using narrow band imaging (NBI) was performed and it was possible to diagnose the mucosal spread lesions of cholangioma. Histological findings reflected the endoscopic findings. Mucosal spread lesions of cholangiocarcinoma were successfully diagnosed using the CHF‐B260 for NBI.


Clinical Endoscopy | 2014

Endosonographic Preoperative Evaluation for Tumors of the Ampulla of Vater Using Endoscopic Ultrasonography and Intraductal Ultrasonography

Naoki Okano; Yoshinori Igarashi; Seiichi Hara; Kensuke Takuma; Itaru Kamata; Yui Kishimoto; Takahiko Mimura; Ken Ito; Yasukiyo Sumino

Background/Aims In recent years, endoscopic snare papillectomy has been performed to treat tumors of the ampulla of Vater. This procedure requires accurate preoperative evaluation. In this study, we diagnosed the focal extension of such tumors by using endoscopic ultrasonography (EUS) and intraductal ultrasonography (IDUS), and examined the indications for endoscopic snare papillectomy. Methods The subjects were 48 patients with a papillary tumor (13 patients, surgical resection; 35 patients, endoscopic snare papillectomy) who were evaluated preoperatively with EUS and IDUS. The tumor-node-metastasis classification was used for the endosonographic evaluation and pathological diagnosis of these tumors. Results The diagnostic accuracy of EUS was 97% for diagnosing adenomas and pTis tumors, 73% for pT1 tumors, 50% for pT2 tumors, and 50% for pT3-4 tumors, for an overall accuracy of 85% for T-staging. The diagnostic accuracy of IDUS was 94% for adenomas and pTis tumors, 73% for pT1 tumors, 50% for pT2 tumors, and 100% for pT3-4 tumors, for an overall accuracy of 80% for T-staging. Conclusions EUS and IDUS are highly capable of evaluating tumors of the ampulla of Vater preoperatively. However, these techniques are not sufficient for evaluating the focal extension of carcinomas preoperatively. Currently, endoscopic snare papillectomy is adequate for treating adenomas and pTis tumors.

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