Ken Kamata

Dr. Ken Kamata


Research Focus & Metrics

Academic Career Length

22Years (2005-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 July 2020 in Ultrasonography
Verified
Journal Article
Open access
PDF file
JLJae Young Lee
Jae Young Lee
Yasunori MinamiYasunori Minami
Yasunori Minami
BCByung Ihn Choi
Byung Ihn Choi
WLWon Jae Lee
Won Jae Lee
YCYi-Hong Chou
Yi-Hong Chou
Masatoshi KudoMasatoshi Kudo
Masatoshi Kudo
The first edition of the guidelines for the use of ultrasound contrast agents was published in 2004, dealing with liver applications. The second edition of the guidelines in 2008 reflected changes in the available contrast agents and updated the guidelines for the liver, as well as implementing some nonliver applications. The third edition of the contrast-enhanced ultrasound (CEUS) guidelines was the joint World Federation for Ultrasound in Medicine and Biology-European Federation of Societies for Ultrasound in Medicine and Biology (WFUMB-EFSUMB) venture in conjunction with other regional US societies such as Asian Federation of Societies for Ultrasound in Medicine and Biology, resulting in a simultaneous duplicate on liver CEUS in the official journals of both WFUMB and EFSUMB in 2013. However, no guidelines were described mainly for Sonazoid due to limited clinical experience only in Japan and Korea. The new proposed consensus statements and recommendations provide general advice on the use of Sonazoid and are intended to create standard protocols for the use and administration of Sonazoid in hepatic and pancreatobiliary applications in Asian patients and to improve patient management.

1 July 2020 in Diagnostics
Verified
Journal Article
Open access
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KYKentaro Yamao
Kentaro Yamao
Mamoru TakenakaMamoru Takenaka
Mamoru Takenaka
RIRei Ishikawa
Rei Ishikawa
AOAyana Okamoto
Ayana Okamoto
TYTomohiro Yamazaki
Tomohiro Yamazaki
Masatoshi KudoMasatoshi Kudo
Masatoshi Kudo
Background: This study aimed to evaluate and identify the specific CT findings by focusing on abnormalities in the main pancreatic duct (MPD) and pancreatic parenchyma in patients with small pancreatic cancer (PC) including carcinoma in situ (CIS). Methods: Nine CT findings indicating abnormalities of MPD and pancreatic parenchyma were selected as candidate findings for the presence of small PC ≤ 10 mm. The proportions of patients positive for each finding were compared between small PC and benign MPD stenosis groups. Interobserver agreement between two independent image reviewers was evaluated using kappa statistics. Results: The final analysis included 24 patients with small PC (including 11 CIS patients) and 28 patients with benign MPD stenosis. The proportion of patients exhibiting partial pancreatic parenchymal atrophy (PPA) corresponding to the distribution of MPD stenosis (45.8% vs. 7.1%, p < 0.01), upstream PPA arising from the site of MPD stenosis (33.3% vs. 3.6%, p = 0.01), and MPD abrupt stenosis (45.8% vs. 14.3%, p = 0.03) was significantly higher in the small PC group than in the benign MPD stenosis group. Conclusions: The presence of partial PPA, upstream PPA, and MPD abrupt stenosis on a CT image was highly suggestive of the presence of small PCs including CIS.

29 September 2018 in Cancers
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Journal Article
Open access
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Naoshi NishidaNaoshi Nishida
Naoshi Nishida
TNTakafumi Nishimura
Takafumi Nishimura
TKToshimi Kaido
Toshimi Kaido
KMKosuke Minaga
Kosuke Minaga
KYKentaro Yamao
Kentaro Yamao
Masatoshi KudoMasatoshi Kudo
Masatoshi Kudo
Hepatocellular carcinoma (HCC) causes one of the most frequent cancer-related deaths; an HCC subset shows rapid progression that affects survival. We clarify molecular features of aggressive HCC, and establish a molecular scoring system that predicts metastasis after curative treatment. In total, 125 HCCs were examined for TP53, CTNNB1, and TERT promoter mutation, methylation of 8 tumor suppressor genes, and 3 repetitive DNA sequences to estimate promoter hypermethylation and global hypomethylation. A fractional allelic loss (FAL) was calculated to represent chromosomal instability through microsatellite analysis. Molecular subclasses were determined using corresponding and hierarchical clustering analyses. Next, twenty-five HCC patients who underwent liver transplantation were analyzed for associations between molecular characteristics and metastatic recurrence; survival analyses were validated using a publicly available dataset of 376 HCC cases from the Cancer Genome Atlas (TCGA). An HCC subtype characterized by TP53 mutation, high FAL, and global hypomethylation was associated with aggressive tumor characteristics, like vascular invasion; CTNNB1 mutation was a feature of the less-progressive phenotype. A number of molecular risk factors, including TP53 mutation, high FAL, significant global hypomethylation, and absence of CTNNB1 mutation, were noted to predict shorter recurrence-free survival in patients who underwent liver transplantation (p = 0.0090 by log-rank test). These findings were validated in a cohort of resected HCC cases from TCGA (p = 0.0076). We concluded that molecular risks determined by common genetic and epigenetic alterations could predict metastatic recurrence after curative treatments, and could be a marker for considering systemic therapy for HCC patients.

20 June 2017 in Digestive Endoscopy
Verified
Journal Article
Open access
PDF file
KKKen Kamata
Ken Kamata
Mamoru TakenakaMamoru Takenaka
Mamoru Takenaka
MKMasayuki Kitano
Masayuki Kitano
SOshunsuke omoto
shunsuke omoto
TMTakeshi Miyata
Takeshi Miyata
MKMasatoshi Kudo
Masatoshi Kudo
Background and Aim: Differential diagnosis of localized gallbladder lesions is challenging. The aim of the present study was to evaluate the utility of contrast‐enhanced harmonic endoscopic ultrasonography (CH‐EUS) for diagnosis of localized gallbladder lesions.Methods: One hundred and twenty‐five patients with localized gallbladder lesions were evaluated by CH‐EUS between March 2007 and February 2014. This was a single‐center retrospective study.Utilities of fundamental B‐mode EUS (FB‐EUS) and CH‐EUS in the differentiation of gallbladder lesions and sludge plug were initially compared. Thereafter, these two examinations were compared with respect to their accuracy in the diagnosis of malignant lesions. Five reviewers blinded to the clinicopathological results evaluated microcirculation patterns in the vascular and perfusion images.Results: In the differentiation between gallbladder lesions and sludge plug, FB‐EUS had a sensitivity, specificity, and accuracy of 82%, 100%, and 95%, respectively, whereas CH‐EUS had a sensitivity, specificity, and accuracy of 100%, 99%, and 99%, respectively. FB‐EUS‐based diagnosis of carcinomas based on tumor size and/or shape had a sensitivity, specificity, and accuracy of 61–87%, 71–88%, and 74–86%, respectively. Additional information regarding irregular vessel patterns in the vascular image and/or heterogeneous enhancement in the perfusion image on CH‐EUS increased the sensitivity, specificity, and accuracy for the diagnosis of carcinomas to 90%, 98%, and 96%, respectively. There was a significant difference between FB‐EUS and CH‐EUS in terms of carcinoma diagnosis.Conclusion: CH‐EUS was useful for the evaluation of localized gallbladder lesions.

7 August 2018 in Digestive Endoscopy
Verified
Journal Article
Closed access
PDF file
KKKen Kamata
Ken Kamata
MKMasayuki Kitano
Masayuki Kitano

5 October 2020 in Digestive Endoscopy
Verified
Journal Article
Closed access
PDF file
RIRei Ishikawa
Rei Ishikawa
KKKen Kamata
Ken Kamata
AHAkane Hara
Akane Hara
HTHidekazu Tanaka
Hidekazu Tanaka
AOAyana Okamoto
Ayana Okamoto
MKMasatoshi Kudo
Masatoshi Kudo