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Dive into the research topics where Kazumasa Seiji is active.

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Featured researches published by Kazumasa Seiji.


Radiographics | 2010

Radiologic-pathologic correlation of ductal carcinoma in situ.

Takayuki Yamada; Naoko Mori; Mika Watanabe; Izo Kimijima; Tadayuki Okumoto; Kazumasa Seiji; Shoki Takahashi

Ductal carcinoma in situ (DCIS) accounts for 20%-25% of breast cancers detected at screening mammography. The lesions are diverse and commonly are classified on the basis of their mammographic features and histologic characteristics such as nuclear grade and presence or absence of necrosis. The most common mammographic finding in DCIS is microcalcifications, but a low-grade lesion without necrosis is less likely to manifest with calcifications than either an intermediate- or a high-grade lesion. Other mammographic findings might include a mass or architectural distortion. Magnetic resonance (MR) imaging has higher sensitivity than mammography for the detection of DCIS and greater accuracy for depicting the extent of disease. The MR imaging appearance of DCIS depends primarily on the presence and extent of abnormal periductal or stromal vascularity. Nonmasslike enhancement, the most common MR imaging finding, is often seen in association with clumped internal enhancement. The enhancement kinetics in dynamic MR studies vary, and no kinetic pattern is pathognomonic of a particular nuclear grade of DCIS. However, the kinetic pattern at delayed imaging does appear to be correlated with the mammographic findings: Mass lesions show strong washout; fine pleomorphic, fine linear, and fine linear-branching calcifications demonstrate a plateau enhancement pattern; and amorphous calcifications exhibit persistent enhancement. Multidetector computed tomography might be a useful adjunct to MR imaging for preoperative mapping.


The Journal of Clinical Endocrinology and Metabolism | 2014

Predictors of decreasing glomerular filtration rate and prevalence of chronic kidney disease after treatment of primary aldosteronism: renal outcome of 213 cases.

Yoshitsugu Iwakura; Ryo Morimoto; Masataka Kudo; Yoshikiyo Ono; Kei Takase; Kazumasa Seiji; Yoichi Arai; Yasuhiro Nakamura; Hironobu Sasano; Sadayoshi Ito; Fumitoshi Satoh

CONTEXT In primary aldosteronism (PA), glomerular hyperfiltration due to excessive aldosterone is considered to underestimate actual renal damage. OBJECTIVE Our objectives were to determine the prevalence of chronic kidney disease (CKD) in PA and identify the predictors of decreasing estimated glomerular filtration rate (eGFR) after treatment. DESIGN AND SETTING This was a 12-month prospective study of patients with PA treated at Tohoku University Hospital. PATIENTS AND INTERVENTIONS All patients were treated according to the results of adrenal venous sampling; 102 patients with aldosterone-producing adenoma underwent adrenalectomy, and 111 with bilateral hyperaldosteronism were treated with mineralocorticoid receptor antagonists. MAIN OUTCOME MEASURES Electrolytes, blood pressure, and indicators of renal function were determined at 1 and 12 months after intervention. RESULTS Blood pressure, urinary albumin excretion (UAE), and eGFR, which significantly decreased at 1 month after treatment of PA, did not further decrease at 12 months. Prevalence of CKD, which was 15.7% in aldosterone-producing adenoma and 8.1% in bilateral hyperaldosteronism at the first visit, increased to 37.1% and 28.3%, respectively, at the end of study (P < .0001). Multivariate regression analysis revealed that higher UAE and lower serum potassium levels were found to be independent predictors of decreasing eGFR after intervention. CONCLUSIONS This large cohort study shows that the prevalence of CKD in PA was increased after treatment and that higher UAE and lower serum potassium levels at the first visit were predictors of decreasing eGFR after treatment of PA. To prevent a large decrease of eGFR after intervention, PA patients should be diagnosed before evolution to severe albuminuria and hypokalemia.


Hypertension | 2014

Different Expression of 11β-Hydroxylase and Aldosterone Synthase Between Aldosterone-Producing Microadenomas and Macroadenomas

Yoshikiyo Ono; Yasuhiro Nakamura; Takashi Maekawa; Saulo J.A. Felizola; Ryo Morimoto; Yoshitsugu Iwakura; Masataka Kudo; Kazumasa Seiji; Kei Takase; Yoichi Arai; Celso E. Gomez-Sanchez; Sadayoshi Ito; Hironobu Sasano; Fumitoshi Satoh

Aldosterone-producing adenoma is a major subtype of primary aldosteronism. The number of cases of these adenomas, which are below the detection limit of computed tomography but diagnosed by adrenal venous sampling, has recently been increasing. However, the pathophysiology of these adenomas, especially those manifesting clinically overt hyperaldosteronism despite their small size, remains unknown. Therefore, we examined the correlation between tumor size and the status of intratumoral steroidogenic enzymes involved in aldosterone biosynthesis using immunohistochemistry. Forty patients with surgically proven aldosterone-producing adenomas were retrospectively studied. Multidetector computed tomography, adrenal venous sampling, and laparoscopic adrenalectomy were performed in all of the patients studied. The tumor area at the maximum diameter of the sections was precisely measured by ImageJ software. The status of the steroidogenic enzymes was immunohistochemically analyzed, and the findings were evaluated according to the H-score system, based on both the number of immunopositive cells and relative immunointensity. Adrenal masses were not detected by computed tomography in 20 patients. Blood pressure, plasma aldosterone concentration, urinary aldosterone excretion, and the number of antihypertensive agents also decreased significantly after the surgery in these patients, as well as in the patients with adenomas detectable by computed tomography. Maximum tumor area obtained in the specimens was significantly correlated with preoperative plasma aldosterone concentration, urinary aldosterone excretion, and the H score of 11&bgr;-hydroxylase and was inversely correlated with the H score of aldosterone synthase. These results demonstrated that small adenomas could produce sufficient aldosterone to cause clinically overt primary aldosteronism because of the significantly higher aldosterone synthase expression per tumor area.


Hypertension | 2015

Measurement of Peripheral Plasma 18-Oxocortisol Can Discriminate Unilateral Adenoma From Bilateral Diseases in Patients With Primary Aldosteronism

Fumitoshi Satoh; Ryo Morimoto; Yoshikiyo Ono; Yoshitsugu Iwakura; Kei Omata; Masataka Kudo; Kei Takase; Kazumasa Seiji; Hidehiko Sasamoto; Seijiro Honma; Mitsunobu Okuyama; Kouwa Yamashita; Celso E. Gomez-Sanchez; William E. Rainey; Yoichi Arai; Hironobu Sasano; Yasuhiro Nakamura; Sadayoshi Ito

Adrenal venous sampling is currently the only reliable method to distinguish unilateral from bilateral diseases in primary aldosteronism. In this study, we attempted to determine whether peripheral plasma levels of 18-oxocortisol (18oxoF) and 18-hydroxycortisol could contribute to the clinical differentiation between aldosteronoma and bilateral hyperaldosteronism in 234 patients with primary aldosteronism, including computed tomography (CT)–detectable aldosteronoma (n=113) and bilateral hyperaldosteronism (n=121), all of whom underwent CT and adrenal venous sampling. All aldosteronomas were surgically resected and the accuracy of diagnosis was clinically and histopathologically confirmed. 18oxoF and 18-hydroxycortisol were measured using liquid chromatography tandem mass spectrometry. Receiver operating characteristic analysis of 18oxoF discrimination of adenoma from hyperplasia demonstrated sensitivity/specificity of 0.83/0.99 at a cut-off value of 4.7 ng/dL, compared with that based on 18-hydroxycortisol (sensitivity/specificity: 0.62/0.96). 18oxoF levels above 6.1 ng/dL or of aldosterone >32.7 ng/dL were found in 95 of 113 patients with aldosteronoma (84%) but in none of 121 bilateral hyperaldosteronism, 30 of whom harbored CT-detectable unilateral nonfunctioning nodules in their adrenals. In addition, 18oxoF levels below 1.2 ng/dL, the lowest in aldosteronoma, were found 52 of the 121 (43%) patients with bilateral hyperaldosteronism. Further analysis of 27 patients with CT-undetectable micro aldosteronomas revealed that 8 of these 27 patients had CT-detectable contralateral adrenal nodules, the highest values of 18oxoF and aldosterone were 4.8 and 24.5 ng/dL, respectively, both below their cut-off levels indicated above. The peripheral plasma 18oxoF concentrations served not only to differentiate aldosteronoma but also could serve to avoid unnecessary surgery for nonfunctioning adrenocortical nodules concurrent with hyperplasia or microadenoma.


European Journal of Endocrinology | 2015

Is there a role for segmental adrenal venous sampling and adrenal sparing surgery in patients with primary aldosteronism

Fumitoshi Satoh; Ryo Morimoto; Kazumasa Seiji; Nozomi Satani; Hideaki Ota; Yoshitsugu Iwakura; Yoshikiyo Ono; Masataka Kudo; Masahiro Nezu; Kei Omata; Yuta Tezuka; Yoshihide Kawasaki; Shigeto Ishidoya; Yoichi Arai; Kei Takase; Yasuhiro Nakamura; Keely May McNamara; Hironobu Sasano; Sadayoshi Ito

OBJECTIVE AND DESIGN Adrenal venous sampling (AVS) is critical to determine the subtype of primary aldosteronism (PA). Central AVS (C-AVS)--that is, the collection of effluents from bilateral adrenal central veins (CV)--sometimes does not allow differentiation between bilateral aldosterone-producing adenomas (APA) and idiopathic hyperaldosteronism. To establish the best treatment course, we have developed segmental AVS (S-AVS); that is, we collect effluents from the tributaries of CV to determine the intra-adrenal sources of aldosterone overproduction. We then evaluated the clinical utility of this novel approach in the diagnosis and treatment of PA. METHODS We performed C-AVS and/or S-AVS in 297 PA patients and assessed the accuracy of diagnosis based on the results of C-AVS (n=138, 46.5%) and S-AVS (n=159, 53.5%) by comparison with those of clinicopathological evaluation of resected specimens. RESULTS S-AVS demonstrated both elevated and attenuated secretion of aldosterone from APA and non-tumorous segments, respectively, in patients with bilateral APA and recurrent APA. These findings were completely confirmed by detailed histopathological examination after surgery. S-AVS, but not C-AVS, also served to identify APA located distal from the CV. CONCLUSIONS Compared to C-AVS, S-AVS served to identify APA in some patients, and its use should expand the pool of patients eligible for adrenal sparing surgery through the identification of unaffected segments, despite the fact that S-AVS requires more expertise and time. Especially, this new technique could enormously benefit patients with bilateral or recurrent APA because of the preservation of non-tumorous glandular tissue.


Hypertension | 2015

Measurement of Peripheral Plasma 18-Oxocortisol Can Discriminate Unilateral Adenoma From Bilateral Diseases in Patients With Primary AldosteronismNovelty and Significance

Fumitoshi Satoh; Ryo Morimoto; Yoshikiyo Ono; Yoshitsugu Iwakura; Kei Omata; Masataka Kudo; Kei Takase; Kazumasa Seiji; Hidehiko Sasamoto; Seijiro Honma; Mitsunobu Okuyama; Kouwa Yamashita; Celso E. Gomez-Sanchez; William E. Rainey; Yoichi Arai; Hironobu Sasano; Yasuhiro Nakamura; Sadayoshi Ito

Adrenal venous sampling is currently the only reliable method to distinguish unilateral from bilateral diseases in primary aldosteronism. In this study, we attempted to determine whether peripheral plasma levels of 18-oxocortisol (18oxoF) and 18-hydroxycortisol could contribute to the clinical differentiation between aldosteronoma and bilateral hyperaldosteronism in 234 patients with primary aldosteronism, including computed tomography (CT)–detectable aldosteronoma (n=113) and bilateral hyperaldosteronism (n=121), all of whom underwent CT and adrenal venous sampling. All aldosteronomas were surgically resected and the accuracy of diagnosis was clinically and histopathologically confirmed. 18oxoF and 18-hydroxycortisol were measured using liquid chromatography tandem mass spectrometry. Receiver operating characteristic analysis of 18oxoF discrimination of adenoma from hyperplasia demonstrated sensitivity/specificity of 0.83/0.99 at a cut-off value of 4.7 ng/dL, compared with that based on 18-hydroxycortisol (sensitivity/specificity: 0.62/0.96). 18oxoF levels above 6.1 ng/dL or of aldosterone >32.7 ng/dL were found in 95 of 113 patients with aldosteronoma (84%) but in none of 121 bilateral hyperaldosteronism, 30 of whom harbored CT-detectable unilateral nonfunctioning nodules in their adrenals. In addition, 18oxoF levels below 1.2 ng/dL, the lowest in aldosteronoma, were found 52 of the 121 (43%) patients with bilateral hyperaldosteronism. Further analysis of 27 patients with CT-undetectable micro aldosteronomas revealed that 8 of these 27 patients had CT-detectable contralateral adrenal nodules, the highest values of 18oxoF and aldosterone were 4.8 and 24.5 ng/dL, respectively, both below their cut-off levels indicated above. The peripheral plasma 18oxoF concentrations served not only to differentiate aldosteronoma but also could serve to avoid unnecessary surgery for nonfunctioning adrenocortical nodules concurrent with hyperplasia or microadenoma.


Journal of Vascular and Interventional Radiology | 2012

Properties of N-Butyl Cyanoacrylate–iodized Oil Mixtures for Arterial Embolization: In Vitro and In Vivo Experiments

Chiaki Takasawa; Kazumasa Seiji; Kenichi Matsunaga; Toshio Matsuhashi; Makoto Ohta; Shuya Shida; Kei Takase; Shoki Takahashi

PURPOSE To examine the properties of N-butyl cyanoacrylate (NBCA) and iodized oil (lipiodol [Lip]) in vitro and in vivo for safe and effective embolization. MATERIALS AND METHODS Viscosity, polymerization time, and diffusing capacity were evaluated according to the NBCA/Lip ratio in vitro. Additionally, the effect of the NBCA/Lip ratio on arterial embolization was evaluated in vivo; various ratios of NBCA/Lip were injected into the renal arteries of adult beagles, after which the embolization effect following transcatheter arterial embolization was quantitatively investigated histopathologically and using computed tomography (CT) volumetry. RESULTS The viscosity of NBCA/Lip increased, polymerization time was prolonged, and diffusing capacity increased as the NBCA density decreased. As the NBCA density decreased, embolic material was recognized in smaller diameter arteries, and embolization of a larger vascular bed was accomplished. The NBCA/Lip mixture with a low density of NBCA was located more peripherally from the catheter tip, and embolization of more peripheral and smaller diameter arteries was achieved. CONCLUSIONS The relationships of properties of NBCA/Lip in vitro and embolization effects in vivo of various ratios of NBCA/Lip were quantitatively examined and compared. The results of this study are useful for safe and effective embolization.


Radiology | 2016

Intra-adrenal Aldosterone Secretion: Segmental Adrenal Venous Sampling for Localization

Nozomi Satani; Hideki Ota; Kazumasa Seiji; Ryo Morimoto; Masataka Kudo; Yoshitsugu Iwakura; Yoshikiyo Ono; Masahiro Nezu; Kei Omata; Sadayoshi Ito; Fumitoshi Satoh; Kei Takase

PURPOSE To use segmental adrenal venous sampling (AVS) (S-AVS) of effluent tributaries (a version of AVS that, in addition to helping identify aldosterone hypersecretion, also enables the evaluation of intra-adrenal hormone distribution) to detect and localize intra-adrenal aldosterone secretion. MATERIALS AND METHODS The institutional review board approved this study, and all patients provided informed consent. S-AVS was performed in 65 patients with primary aldosteronism (34 men; mean age, 50.9 years ± 11 [standard deviation]). A microcatheter was inserted in first-degree tributary veins. Unilateral aldosterone hypersecretion at the adrenal central vein was determined according to the lateralization index after cosyntropin stimulation. Excess aldosterone secretion at the adrenal tributary vein was considered to be present when the aldosterone/cortisol ratio from this vein exceeded that from the external iliac vein; suppressed secretion was indicated by the opposite pattern. Categoric variables were expressed as numbers and percentages; continuous variables were expressed as means ± standard errors of the mean. RESULTS The AVS success rate, indicated by a selectivity index of 5 or greater, was 98% (64 of 65). The mean numbers of sampled tributaries on the left and right sides were 2.11 and 1.02, respectively. The following diagnoses were made on the basis of S-AVS results: unilateral aldosterone hypersecretion in 30 patients, bilateral hypersecretion without suppressed segments in 22 patients, and bilateral hypersecretion with at least one suppressed segment in 12 patients. None of the patients experienced severe complications. CONCLUSION S-AVS could be used to identify heterogeneous intra-adrenal aldosterone secretion. Patients who have bilateral aldosterone-producing adenomas can be treated with adrenal-sparing surgery or other minimally invasive local therapies if any suppressed segment is identified at S-AVS.


Journal of Human Hypertension | 2016

A case of bilateral aldosterone-producing adenomas differentiated by segmental adrenal venous sampling for bilateral adrenal sparing surgery

Ryo Morimoto; Nozomi Satani; Yoshitsugu Iwakura; Yoshikiyo Ono; Masataka Kudo; Masahiro Nezu; Kei Omata; Yuta Tezuka; Kazumasa Seiji; Hideki Ota; Yoshihide Kawasaki; Shigeto Ishidoya; Yasuhiro Nakamura; Yoichi Arai; Kei Takase; Hironobu Sasano; Sadayoshi Ito; Fumitoshi Satoh

Primary aldosteronism due to unilateral aldosterone-producing adenoma (APA) is a surgically curable form of hypertension. Bilateral APA can also be surgically curable in theory but few successful cases can be found in the literature. It has been reported that even using successful adrenal venous sampling (AVS) via bilateral adrenal central veins, it is extremely difficult to differentiate bilateral APA from bilateral idiopathic hyperaldosteronism (IHA) harbouring computed tomography (CT)-detectable bilateral adrenocortical nodules. We report a case of bilateral APA diagnosed by segmental AVS (S-AVS) and blood sampling via intra-adrenal first-degree tributary veins to localize the sites of intra-adrenal hormone production. A 36-year-old man with marked long-standing hypertension was referred to us with a clinical diagnosis of bilateral APA. He had typical clinical and laboratory profiles of marked hypertension, hypokalaemia, elevated plasma aldosterone concentration (PAC) of 45.1 ng dl−1 and aldosterone renin activity ratio of 90.2 (ng dl−1 per ng ml−1 h−1), which was still high after 50 mg-captopril loading. CT revealed bilateral adrenocortical tumours of 10 and 12 mm in diameter on the right and left sides, respectively. S-AVS confirmed excess aldosterone secretion from a tumour segment vein and suppressed secretion from a non-tumour segment vein bilaterally, leading to the diagnosis of bilateral APA. The patient underwent simultaneous bilateral sparing adrenalectomy. Histopathological analysis of the resected adrenals together with decreased blood pressure and PAC of 5.2 ng dl−1 confirmed the removal of bilateral APA. S-AVS was reliable to differentiate bilateral APA from IHA by direct evaluation of intra-adrenal hormone production.


International Journal of Radiation Oncology Biology Physics | 2003

A novel support system for patient immobilization and transportation for daily computed tomographic localization of target prior to radiation therapy

Kenji Nemoto; Kazumasa Seiji; Kazuya Sasaki; Nobutaka Kasamatsu; Toshie Fujishima; Yoshihiro Ogawa; Hisanori Ariga; Ken Takeda; Tokihisa Kimura; Shogo Yamada

PURPOSE To develop a method for quick and smooth transportation of patients from a computed tomography (CT) table to a linear accelerator (linac) table for confirming tumor center before radiation therapy. MATERIALS AND METHODS We developed a system using a subtable for patient immobilization that is transported via a customized stretcher. The patient lies on the subtable and is immobilized by a vacuum cushion and thermoplastic body cast. The subtable stretcher is used to carry the subtable from the CT table to the linac table. During transportation, the subtable is kept flat and shock to the subtable is carefully avoided. Between August 2001 and September 2002, a total of 9 patients with solitary upper lung tumors (superior to carina) were treated using this system. RESULTS Intrafractional tumor motion along the x (left-right), y (anterior-posterior), and z axis (superior-inferior) ranged from -2 mm to 2 mm, -2 mm to 2 mm, and -5 mm to 3 mm, respectively. The standard deviation of intrafractional tumor motion along the x, y, and z axis ranged from 0.5 mm to 1.5 mm, 0 mm to 1.7 mm, and 0.6 mm to 3.5 mm, respectively. Interfractional setup errors along the x, y, and z axis ranged from -5 mm to 4 mm, -6 mm to 8 mm, and -6 mm to 6 mm, respectively, and we could reduce interfractional setup errors in the majority of treatment sessions. CONCLUSIONS We developed a system that allows patients to be immobilized and transported to verify tumor location on a daily basis. This system is highly useful for reducing setup errors.

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