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Featured researches published by M. Nakajo.


Acta Radiologica | 2003

Intraductal Papillary Mucinous Tumors of the Pancreas

Yoshihiko Fukukura; Fumito Fujiyoshi; Hiroyuki Hamada; Sonshin Takao; Takashi Aikou; N. Hamada; Suguru Yonezawa; M. Nakajo

Purpose: To compare the effectiveness of thin-section helical CT and MR imaging with gadolinium-enhanced dynamic technique and MR cholangiopancreatography (MRCP) in the examination of patients with intraductal papillary mucinous tumors. Material and Methods: Helical CT, dynamic MR imaging, and MRCP of 25 intraductal papillary mucinous tumors were compared with ERCP and surgical findings. Results: The duodenal papilla was identified by helical CT and dynamic MR imaging in 11 (44%) and 20 (80%) of the 25 patients, respectively (p<0.05). The main pancreatic duct was visualized on helical CT, dynamic MR imaging, and MRCP in all patients (100%): 25 (96.2%), 24 (92.3%), and 26 (100%) cystic lesions were depicted, respectively. A communicating duct between the main pancreatic duct and the cystic lesion was visualized on helical CT, dynamic MR imaging, and MRCP in 14 (53.8%), 11 (42.3%), and 15 (55.7%) lesions, respectively. The papillary projections corresponding to 3 mm or larger papillary neoplasms were depicted on helical CT and MR imaging in 7 patients (25%). Conclusion: MR imaging was equal or slightly superior to thin-section helical CT in the evaluation of intraductal papillary mucinous tumors.


Acta Radiologica | 2000

HEPATIC FALCIFORM ARTERY: Angiographic findings in 25 patients

Yasutaka Baba; Nobuaki Miyazono; Kazuto Ueno; I. Kanetsuki; H. Nishi; Hiroki Inoue; M. Nakajo

Purpose: To determine the frequency of hepatic falciform artery (HFA) occurrence on celiac or hepatic angiograms and elucidate the anatomy and clinical importance. Material and Methods: Among 1,250 patients who underwent celiac or hepatic arteriography, we encountered 25 patients (2%) with a HFA. Prospectively, CT hepatic falciform arteriography (CTHA) was performed in 4 patients. Indigocarmine dye was injected into the HFA in 6 patients to evaluate whether the abdominal skin was stained. Embolization of the HFA before chemoembolization for hepatocellular carcinoma was performed in 4 patients to prevent abdominal wall injury. Results: Among 25 patients, the HFA arose as a terminal branch of the middle hepatic artery in 14 patients (56%) and of the left hepatic artery in 11 patients (44%). The vessel was single in 18 patients (72%) and double in 7 patients (28%). Two vessels ran side by side along the hepatic falciform ligament. On CTHA, the HFA ran within the hepatic falciform ligament and the branches were connected with the liver around the hepatic falciform ligament. After indigocarmine dye injection, the stain of abdominal skin was recognized in all 6 patients. No abdominal wall injury occurred in any of the 4 patients who were subjected to hepatic chemoembolization. Conclusion: HFA is an extrahepatic pathway which runs to the abdominal wall. Before chemoembolization of the middle or left hepatic artery for hepatic malignancy, the HFA should be recognized.


Journal of Computer Assisted Tomography | 2000

Intrahepatic portal venous variations : Demonstration by helical CT during arterial portography

Yasutaka Baba; Hirofumi Hokotate; H. Nishi; Hiroki Inoue; M. Nakajo

Purpose We assessed the prevalence and types of intrahepatic portal venous variations by helical computed tomography performed with arterial portography (CTAP). Methods In 192 patients without evidence of vascular invasion or distortion, CTAP images were reviewed retrospectively to identify portal venous variations. Results Of the 192 patients examined, 10 (5.2%) had trifurcation, 5 (2.6%) had a right posterior segmental branch arising from the main portal vein, 5 (2.6%) had an absence of the horizontal segment of the left portal vein, and 1 (0.5%) had an absence of the left lateral segmental portal branch. Of the patients without a horizontal segment, two had a right-sided ligamentum teres associated with malposition of the gallbladder, while another had complete ramification of intrahepatic portal branches from an umbilical vein-like segment. In the patient missing the left lateral segmental branches, the right portal vein segments were subcapsularly located. Conclusion Variations of the intrahepatic portal veins can be recognized on CTAP imaging.


Abdominal Imaging | 2000

Altered flow dynamics of intravascular contrast material to the liver in superior vena cava syndrome: CT findings

Yasutaka Baba; Nobuaki Miyazono; Hiroki Inoue; I. Kanetsuki; H. Niwatsukino; D. Tanaka; H. Nishi; T. Nandate; K. Ohkubo; M. Nakajo

AbstractBackground: To evaluate the findings of altered flow dynamics in the livers of patients with obstruction of superior vena cava (SVC) on helical computed tomography (CT). Methods: In six patients (age range = 28–80 years) with SVC obstruction, CT findings were retrospectively reviewed to identify the abnormal enhancement patterns of the liver and the relation with the extrahepatic collateral vessels and hepatic vessels. Results: Abnormal hepatic enhancement was observed in the following four (A–D) portions: (A) anterior portion of segment IV (n = 5), (B) subdiaphragmatic portion of the liver (n = 4), (C) posterior portion of the right lobe (bare area; n = 1), and (D) lateral segment of the left lobe (n = 2). Two major collateral pathways to the liver were demonstrated as follows: A and D → from the umbilical vein to the left portal vein, and B and C → from the subcapsular vein to the bare area of the liver or to the hepatic veins. On helical CT, these collateral pathways were also clearly visualized. Conclusion: When these abnormal enhancements of the liver on CT are recognized within the liver, these findings indicate diversion of contrast material into collateral pathways to the liver with SVC obstruction.


Journal of Computer Assisted Tomography | 2003

Computed tomography and magnetic resonance imaging findings of brain damage by hanging.

M. Nakajo; Onohara S; Shinmura K; Amitani H; Munamoto T; Yasutaka Baba

We reported computed tomography (CT) and magnetic resonance imaging (MRI) findings of brain damage of a 61-year-old man who attempted suicide by hanging. Unenhanced CT demonstrated multiple hyperdense areas indicating subcortical and subarachnoid hemorrhages and brain swelling. MRI demonstrated not only hemorrhagic findings, but also ischemic findings in the middle brain and cerebral cortex. Multifocal cerebral hemorrhages might be caused by venous hypertension due to compression of the jugular veins.


Diseases of The Esophagus | 2003

Long-term survivors of advanced esophageal cancer without surgical treatment: a multicenter questionnaire survey in Kyushu, Japan

Shoji Natsugoe; M. Ikeda; Masamichi Baba; H. Churei; Yoshiyuki Hiraki; M. Nakajo; Takashi Aikou

SUMMARY Since the introduction of recent improvements in adjuvant therapy for esophageal cancer, some patients have demonstrated good prognosis. In the present study, we analyzed 3- and 5-year survivors of advanced esophageal cancer who did not undergo any surgical treatment. Between 1990 and 1998, 831 patients were admitted to 14 university hospitals and one cancer center associated with the membership of the Kyushu study group for adjuvant therapy of esophageal cancer. Twelve (1.4%) of the patients were 3-year survivors and 13 (1.6%) were 5-year survivors. The reasons for non-operation were refusal (eight patients), tumor-related factors (11 patients), and host-related factors (six patients). With a single exception, all patients had locally advanced tumors. Almost all long-term survivors had fewer than five lymph node metastases, in regions limited to the neck and/or mediastinum. Radiation therapy was combined with chemotherapy for 16 of the 25 patients, and chemotherapy-based cisplatin was used for 15 of these 16 patients. Fifteen of the patients remain alive; 10 died seven of them from esophageal cancer. Chemoradiation therapy was effective for some patients with locally advanced esophageal cancer, particularly in the absence of or with few lymph node metastases. To improve the prognosis of patients with advanced esophageal cancer who, for various causes, cannot undergo surgical treatment, a new protocol for adjuvant therapy is required.


Abdominal Imaging | 2003

Left renal vein aneurysm: imaging findings

Tomohide Yoneyama; Yasutaka Baba; Fumito Fujiyoshi; Hirohumi Hokotate; Hiroki Inoue; M. Nakajo

AbstractA renal vein aneurysm is a rare vascular disease. To our knowledge, only six cases have been reported. We describe a 57-year-old woman with a left renal vein aneurysm diagnosed by a combination of ultrasonography, color Doppler ultrasonography, contrast-enhanced computed tomography, and magnetic resonance imaging.


International Journal of Hyperthermia | 2000

The position of the opposite flat applicator changes the SAR and thermal distributions of the RF capacitive intracavitary hyperthermia.

Yoshiyuki Hiraki; M. Nakajo; Tsuyoshi Takeshita; Hisahiko Churei

The variations of the specific absorption rate (SAR) and thermal distribution in the JSHO QA phantoms were investigated by radiofrequency (RF) capacitive intracavitary hyperthermia (ICHT) applicator (AP-T01, Omron Electric Co., Kyoto, Japan) with the changing position of the opposite flat applicator (15-cm in diameter). The thermal distribution was observed with the thermographic camera and the normalized SAR distribution was calculated with the thermal data that were measured with the thermocouple thermometers. The SAR and thermal distributions of AP-T01 significantly varied with the position of the opposite flat applicator. The slope of the normalized SAR became gradual towards the side of the flat applicator. During the operating of a high flow rate (1500ml/min) cooling system, the region between AP-T01 and the flat applicator was widely and rather homogeneously heated, except the hot spot around the end of AP-T01. This hot spot may be due to the imbalance of cooling of AP-T01 and the warming-up of the electrode. These results suggest that the RF capacitive ICHT using AP-T01 may be clinically effective on the deep-seated tumours in the direction of either the end wall, such as cervical cancers, or the upper wall, such as prostatic cancers and the mediastinal metastatic lymph nodes, if an improvement of the cooling system is achieved.


Biomedicine & Pharmacotherapy | 2000

Non-surgical therapy of primary aldosteronism: transcatheter arterial infusion of ethanol into an aldosteronoma.

M. Nakajo; Hirohumi Hokotate; Shinsaku Tsuchimochi; Hiroki Inoue; Nobuaki Miyazono

Primary aldosteronism due to an adrenocortical adenoma can be cured by ablation of the adenoma, which produces an excess of aldosterone (aldosteronoma). This has traditionally been performed by surgical removal of the adenoma. However, some patients with aldosteronomas refuse surgical removal. Therefore, we developed a therapeutic method to ablate an aldosteronoma by transcatheter arterial infusion of ethanol. This method ablated the aldosteronoma in 27 (82%) of 33 treated cases and produced no serious complications, and may be one of the therapeutic choices for aldosteronomas.


International Journal of Hyperthermia | 2000

The size and distance of the opposite flat applicator change the SAR and thermal distributions of RF capacitive intracavitary hyperthermia.

Yoshiyuki Hiraki; M. Nakajo; Tsuyoshi Takeshita; Hisahiko Churei

The variations of the specific absorption rate (SAR) and thermal distributions in the JSHO QA phantom were investigated by using the radiofrequency (RF) capacitive intracavitary hyperthermia (ICHT) applicator (AP-T01, Omron Electric Co., Kyoto, Japan) and the opposite flat applicators of different sizes (AP-75E: 7.5cm in diameter, AP-100E: 10cm in diameter, and AP-150E: 15cm in diameter). The influences of the distance between both applicators were also investigated. Heating of the region between both applicators became weaker with the increase in size of the opposite flat applicator, and it became stronger with the decrease of the distance between both applicators. Heating near the flat applicator became weaker with the increase in size of the flat applicators, and it showed no apparent difference with the increase of the distance between both applicators. The normalized SAR values between AP-T01 and the opposite flat applicator became smaller and its slope became steeper with the increase in size of the opposite flat applicator and in the distance between both applicators. These results suggest that the variability of the specific absorption rate (SAR) and thermal distributions of the region between both applicators may show the potentiality of usefulness for heating the tumours of various sizes, shapes and location.

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H. Nishi

Kagoshima University

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