Kyushu University Academic Staff Educational and Research Activities Database
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Asayama Yoshiki Last modified date:2019.05.30

Professor / Department of Advanced Imaging and Interventional Radiology
Faculty of Medical Sciences


Graduate School
Undergraduate School


Homepage
http://www.radiol.med.kyushu-u.ac.jp/index.html
Department of Clinical Radiology Kyushu University .
Phone
092-642-5695
Fax
092-642-5708
Academic Degree
Ph.D
Country of degree conferring institution (Overseas)
No
Field of Specialization
Abdominal imaging, Interventional Radiology
Total Priod of education and research career in the foreign country
00years00months
Outline Activities
Radiological Imaging of hepatic tumor
Interventional radiology
Research
Research Interests
  • Biliary tract image quality with a deep learning-based reconstruction algorithm at drip infusion cholangiographic ultra-high resolution CT
    keyword : Ultra-high resolution CT, biliary anatomy
    2018.03~2019.12.
  • mage quality and radiation dose of renal perfusion CT with low contrast agent: a comparison with conventional CT using 320-row scanner
    keyword : perfusion CT, image quality, radiation dose
    2017.06~2018.06.
  • Usefulness of a modified RENAL nephrometry score in predicting renal function after cryotherapy for renal mass
    keyword : renal cell carcinoma, cryoablation, cryotherapy, renal function
    2017.06~2018.08.
  • Predictors of cryoablation for renal cell carcinoma
    keyword : renal cell carcinoma, cryoablation, predictors of prognosis, CT, MRI, US
    2016.12~2018.06.
  • Predictors of therapeutic effect after transarterial Chemoembolization using drug-eluting beads for hepatocellular carcinoma
    keyword : hepatocellular carcinoma, HCC, microsphere, DEB-TACE
    2015.06~2017.06.
  • Prognostic significance of contrast-enhanced CT attenuation value in extrahepatic cholangiocarcinoma
    keyword : extrahepatic cholangiocarcinoma, computed tomography, prognosis
    2015.09~2016.07.
  • Histogram analysis of noncancerous liver parenchyma on gadoxetic acid-enhanced MRI: predictive value for liver function and pathology.
    keyword : EOB MRI hepatocellular carcinoma risk factor
    2015.01~2016.02.
  • Fatty change in poorly differentiated hepatocellular carcinoma: possible mechanism in relation to decreased arterial flow
    keyword : hepatocellular carcinoma, fatty chage, feeding artery, MRI
    2012.06~2016.02.
  • Histogram analysis of noncancerous liver parenchyma on gadoxetic acid-enhanced MRI: predictive value for liver function and pathology.
    keyword : EOB MRI hepatocellular carcinoma risk factor
    2015.01~2016.01.
  • Hemodynamic change of hepatic arterial flow under balloon-occluded transcatheter arterial chemoembolization
    keyword : balloon-occlusion, hepatic arterial flow, b-TACE
    2014.03~2016.06.
  • Distinguishing intrahepatic cholangiocarcinoma from poorly differentiated hepatocellular carcinoma with gadoxetic acid-enhanced MRI
    keyword : intrahepatic cholangiocarcinoma, hepatocellular carcinoma, MRI, gadoxetic acid
    2011.05~2014.12.
  • Imaginf findings of the liver tumor originating from hepatic progenitor cell
    keyword : hepatic progenitor cell, CT, MRI
    2009.04~2011.03Imagings of cholangiolocellular carcinoma.
  • CT-guided Radiofrequency ablation of osteoid osteoma
    keyword : osteoid osteoma, CT radiofrequency ablation
    2010.10~2011.05.
  • The differentiation of well differentiated hepatocellular carcinoma from borderline lesion using EOB-MRI
    keyword : liver MRI hepatocellular carcinoma EOB
    2008.09~2011.03.
  • Radiologic imaging findings of liver tumors

    keyword : liver CT, MRI, angiography
    2008.09~2011.03Imaging findings of liver tumor.
  • Imaging findings of cholangiolocellular carcinoma
    keyword : cholangiolocellular carcinoma, CT, MRI
    2008.11~2009.06.
Academic Activities
Presentations
1. Yoshiki Asayama, Akihiro Nishie, Kousei Ishigami, Yasuhiro Ushijima, Daisuke Kakihara, Nobuhiro Fujita, Koichiro Morita, Keisuke Ishimatsu, Seiichiro Takao and Hiroshi Honda, Atypical and mimicking hepatocellular carcinoma: evaluated by LI-RADS 2017, Radiological Society of North America, 2018.11.
2. Yoshiki Asayama, Akihiro Nishie, Kousei Ishigami, Yasuhiro Ushijima, Daisuke Kakihara, Nobuhiro Fujita, Koichiro Morita, Keisuke Ishimatsu, Seiichiro Takao, and Hiroshi Honda., Usefulness of a modified RENAL nephrometry score in predicting renal function after cryotherapy for renal mass, Radiological Society of North America, 2018.11, [Purpose] The aim of this study was to investigate the application of the modified RENAL nephrometry (MRN) score system in predicting renal function after cryotheraphy in T1 renal mass patients.
[Materials and Methods] A total of 75 patients with T1 renal cell carcinoma were enrolled. MRN score is based on age, clinical history of cerebro-cardiovascular events, tumor size as maximal diameter, exophytic/endophytic properties of the tumor, nearness of the tumor to the collecting system, and anterior/posterior location of the kidney. The change in estimated glomerular filtration rate (ΔeGFR) was calculated as follows: ΔeGFR= 100 x ([eGFR at pretreatment – eGFR at 6 months after cryotherapy]/ eGFR at pretreatment). On the basis of the ΔeGFR, we classified the cases into two groups, preserved group (ΔeGFR <10%) and impaired group (ΔeGFR >10%). Association of between MRN score and change in eGFR was analysed.
[Results] The mean ΔeGFR was 5.5%. MRN score in preserved group (6.9±0.2) was significantly lower than that in impaired group (8.3±0.3) (p<0.001). In the setting of MRN score cutoff value of 8 point, sensitivity, specificity, positive predictive value, negative predictive value and accuracy of predicting renal impairment were 64.5%, 77.3%, 66.7%, 75.6% and 72%, respectively
[Conclusion] The modified RENAL nephrometry score is useful in predicting renal function after renal cryotherapy..
3. Yoshiki Asayama, Predictive role of MRI-post treatment outcom, 3rd Asia Pacific Liver Imaging Symposium (APLIS) 2018, 2018.10.
4. Yoshiki Asayama, Akihiro Nishie, Kousei Ishigami, Yasuhiro Ushijima, Daisuke Okamoto, Nobuhiro Fujita, Koichiro Morita, Keisuke Ishimatsu, Seiichiro Takao, and Hiroshi Honda., Image quality and radiation dose of renal perfusion CT with low contrast agent: a comparison with conventional CT using 320-row scanner, European Congress of Radiology, 2018.03, [Purpose] To compare perfusion CT with reconstructed image from source data using low contrast agent and conventional 320-row CT in the light of image quality and radiation dose for the evaluation of renal tumor.
[Materials and Methods] This study collected 37 patients who were candidate for cryotherapy for renal tumor. We scanned 25 patients using 64-row scanner between January 2015 and September 2016 and 12 patients using perfusion CT with 320-row scanner between October 2016 and March 2017. Subjective image quality (image noise, vascular visualization, contrast enhancement, image sharpness, and overall image quality) was assessed with on a four-point scale. Quantitative image parameters including CT attenuation, image noise and the contrast-to-noise ratio (CNR) was were measured. The volume CT dose index (CTDIvol), dose length product (DLP) and the size-specific dose estimate (SSDE) were recorded.
[Results] Conventional CT tended to show higher subjective image quality, but the level of significance was not reached. The CT attenuation (Hounsfield Unit, HU) of aorta and left/right renal arteries was significantly higher in perfusion CT than in conventional CT (p<0.05) (404.7±16.2 vs. 315.5 ± 12.7, 368.3 ± 19.1 vs. 315.9 ± 14.9, and 372.6 ± 17.4 vs. 301.2 ± 13.6, respectively). The CNR of them was also significantly higher (p<0.05) (29.7 ±2.8 vs. 21.9 ± 2.2, 26.5 ± 2.4 vs. 21.7 ± 1.9 and 27.1 ± 2.7 vs 20.6 ± 2.1, respectively). In contrast, Contrast enhancement (HU) and CNR of renal cortex were significantly lower in perfusion CT than in conventional CT (p<0.05) (218.1 ±14.7 vs 264.5 ±11.5 and 12.1 ± 1.4 vs. 16.6 ± 1.1, respectively). Image noise was equivalent for the two protocols. The CTDIvol (mGy), DLP (mGy cm) and SSDE (mGy) of perfusion CT were significantly lower than those of conventional CT (p<0.05) (91.1 ± 16.2 vs. 233.5 ±12.7, 2219.9 ± 389.2 vs. 3330.1 ± 294.2 and 151.7 ± 39.8 vs. 364.2 ± 56.9, respectively).
[Conclusion] The perfusion CT with reconstructed image from source data showed significant dose reduction with acceptable image quality degradation compared with conventional CT. “

Clinical Relevance
As a perfusion CT makes it possible to perform diagnostic-quality studies with low radiation expose. Therefore, perfusion CT, even in a research purpose, may be a substitute for conventional CT..
5. Purpose: The aim of this study was to reveal the relationship between intratumoral uptake of gadoliniumethoxylbenzyldiethylenetriaminepentaacetic acid (Gd-EOB-DTPA) of hepatocellular carcinoma (HCC) in the hepatobiliary phase and pathological features.
Materials and Methods: Sixty HCC nodules were confirmed at pathology in 56 patients who had undergone dynamic MRI. T1-weighted 3D gradient echo sequences before and 20 minutes (hepatobiliary phase) after the injection of Gd-EOB-DTPA were performed. Uptake of Gd-EOB-DTPA was defined as an increase in signal intensity in the hepatobiliary phase compared with the precontrast scan. All surgical specimens were fixed with formalin and then digitally photographed. The relationship between Gd-EOB-DTPA uptake and histological findings, including a macroscopic greenish area, was examined.
Results: MR images showed uptake of Gd-EOB-DTPA in twenty-two nodules. Histological findings indicated twenty-six nodules contained a greenish area. There is a significant correlation between HCC showing Gd-EOB-DTPA uptake and the presence of a greenish area (p < 0.001). On a nodule-by-nodule basis, more than two-thirds of the area of Gd-EOB DTPA uptake coincides with the greenish part in only 12 of 22 lesions (54.5%). More than two-thirds of the greenish area coincided with that of Gd-EOB-DTPA uptake in only 10 of 26 cases (38.5%).
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Membership in Academic Society
  • Japan Radiological Society
  • The Japanese Society of Interventional Radiology
  • Radiological Society of North America
  • Japan Society for Low Temperature Medicine
  • Liver Cancer Study Group of Japan
Educational
Other Educational Activities
  • 2013.04.