Toshiaki Nishii

Publications (6)10.88 Total impact

• Article: Comparison of201Tl-chloride SPECT with99mTc-MIBI SPECT in the depiction of malignant head and neck tumors

  Noriaki Tomura, Osamu Watanabe, Satoshi Takahashi, Ikuo Sakuma, Takahiro Otani, Toshiaki Nishii, Jiro Watarai
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  ABSTRACT: ObjectiveComparison of201T1 chloride SPECT (Tl-SPECT) with99mTc-MIBI SPECT (MIBI-SPECT) in the depiction of malignant head and neck tumors was prospectively studied. MethodsForty-one patients with various tumors of the head and neck were included in this prospective study. Histologically, 36 patients had squamous cell carcinomas, 3 undifferentiated carcinomas, 1 transitional cell carcinoma, and 1 MALT lymphoma. All patients underwent a simultaneous dual-isotope SPECT of the head and neck with201Tl and99mTc-MIBI. Dual-isotope SPECT for early (n = 41) and delayed acquisition (n = 21) was performed. Qualitatively, 3 observers evaluated both Tl-SPECT and MIBI-SPECT individually. The interpretation criteria were graded as grade 1 (no abnormal increased uptake) to 5 (definitely increased uptake of a degree equal to or greater than that of normal salivary gland). Statistical analysis of the comparison of Tl-SPECT and MIBI-SPECT was performed. The interobserver difference was evaluated using the κ-coefficient. Quantitatively, T/N ratio (the ratio of the counts in the tumor divided by that in the normal nuchal muscles) and retention index were compared between Tl-SPECT and MIBI-SPECT. ResultsOn both the early and delayed images, the grades of uptake of the tumor in Tl-SPECT were significantly higher than those in MIBI-SPECT by three observers. The grade of T1-uptake of the tumor on the delayed images was 5 for all observers (κ-coefficient =1); however, the κ-coefficient varied from 0.39 to 0.84 in early Tl-SPECT, and in early and delayed MIBI-SPECT. Statistical differences in T/N ratio were noted between early Tl-SPECT (2.87 ± 1.19) and MIBI-SPECT (2.48 ± 1.06), and between delayed Tl-SPECT (2.11 ± 0.70) and MIBI-SPECT ( 1.20 ± 0.48). The retention index of Tl-SPECT (0.81 ± 0.24) was significantly higher than that of MIBI-SPECT (0.52 ± 0.15). ConclusionsThe present study qualitatively and quantitatively showed that201T1 had higher accumulation in the tumor than99mTc-MIBI in both early and delayed images.
  Annals of Nuclear Medicine 04/2012; 20(2):107-114. · 1.50 Impact Factor
• Article: Three-dimensional bone-free computed tomographic angiography of aneurysms near the skull base using a new bone-removal application.

  Noriaki Tomura, Takahiro Otani, Ikuo Sakuma, Satoshi Takahashi, Toshiaki Nishii, Jiro Watarai
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  ABSTRACT: Bone elimination is needed for computed tomography angiography (CTA) because bone structures obscure aneurysms located at the skull base. The purpose of our study was to evaluate the efficacy of three-dimensional (3D)-CTA using an application for bone elimination. A total of 27 patients with 32 angiographically confirmed aneurysms near the skull base were investigated. The 3D maximum intensity projection (MIP) images were initially obtained using the application. Further postprocessing was performed to obtain the MIP and volume-rendered (VR) images. The quality of the initial MIP images by the application was analyzed. Visualization of aneurysms after further processing was also reviewed. The initial MIP images by the application showed almost bone-free images in 23 of the 27 patients. In 8 patients, the image of the internal carotid artery (ICA) was segmentally removed in the initial MIP images by the application. Further postprocessing was able to recover all loss of the ICA image in these eight patients. For visualizing aneurysms and their necks, VR images with the application were significantly superior to VR images without the application. The application for bone elimination allows fast, selective elimination of bony structures and can improve the interpretation of aneurysms near the skull base.
  Japanese journal of radiology 02/2009; 27(1):31-6. · 0.65 Impact Factor
• Article: Hepatic infarction following selective hepatic artery embolization with microcoils for iatrogenic biliary hemorrhage.

  Manabu Hashimoto, Yoko Akabane, Jyouichi Heianna, Etuko Tate, Koichi Ishiyama, Toshiaki Nishii, Jiro Watarai
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  ABSTRACT: Purpose: The aim of this study was to explore the relation of collateral filling to ischemic or infarcted liver following selective embolization of hepatic artery with microcoils in patients with iatrogenic hemobilia. Methods: We performed retrospective analysis of clinical outcomes and post-embolization angiograms in eight patients (mean age of 66 years) studied over the last 7 years. Hemobilia occurred after percutaneous biliary drainage (n = 5) and percutaneous hepatic biopsy (n = 3). Causes of bleeding were pseudoaneurysm (n = 6), arterial laceration (n = 1), and direct hepatic artery-to-biliary duct fistula (n = 1). We placed microcoils in the subsegmental (n = 4) or segmental branch (n = 2), or both branches (n = 2), distal and proximal to the bleeding point. Results: We obtained complete hemostasis in all patients (100%). Four patients had no hepatic infarction after embolization. Normal filling of the distal part of the embolized branch through collaterals was seen on post-embolization films. Four patients with no collateral filling experienced liver infarction in the area corresponding to embolized branch. One patient with severe portal stenosis died of hepatic failure. Conclusion: Hepatic infarction is related to lack of immediate collateral flow.
  Hepatology Research 10/2004; 30(1):42-50. · 2.20 Impact Factor
• Article: Small veins entering the liver.

  Manabu Hashimoto, Jyouiti Heianna, Etuko Tate, Toshiaki Nishii, Takahide Iwama, Koichi Ishiyama
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  ABSTRACT: It is important to recognize and understand focal fatty infiltration and pseudolesions of the liver mimicking liver tumors on CT during arterial portography or helical-CT images. These conditions are caused by venous flow outside the main portal vein. Unless this is borne in mind, incorrect diagnosis and management may follow. This article demonstrates the appearance of the parenchymal changes caused by systemic venous flow and location of the systemic veins entering the liver parenchyma.
  European Radiology 09/2002; 12(8):2000-5. · 3.22 Impact Factor
• Article: Reduced perfusion reserve in Leukoaraiosis demonstrated using acetazolamide challenge 123I-IMP SPECT.

  Noriaki Tomura, Kazuhumi Sasaki, Hiroyuki Kidani, Toshiaki Nishii, Kaku Yasuda, Koichi Ishiyama, Takahiro Otani, Ikuo Sakuma, Satoshi Takahashi, Jiro Watarai, Toshiharu Yanagisawa, Kazuo Mizoi
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  ABSTRACT: We examined the relationship between the perfusion reserve as measured by acetazolamide (ACZ)-challenge N-isopropyl-I-123-p-iodoamphetamine (IMP)-single-photon emission computed tomography (SPECT) and the degree of leukoaraiosis (LA) as estimated using magnetic resonance imaging. In 51 patients receiving IMP-SPECT with the resting state and ACZ challenge, the unaffected cerebral hemispheres were included in the present study. Mean cerebral blood flow (CBF) in the resting state and ACZ reactivity were acquired. Absolute CBF value and ACZ reactivity were compared among patients with LA grades 0, 1, and 2. The relationship between mean age and LA grade was also assessed. No significant difference in the absolute CBF value in the resting state was observed among the 3 LA groups. Although vasoreactivity in LA grade 0 did not differ from that in grade 1, vasoreactivity in LA grade 2 was significantly lower (P < 0.05) than that in grades 0 or 1. The perfusion reserve is impaired in advanced LA.
  Journal of Computer Assisted Tomography 31(6):884-7. · 1.22 Impact Factor
• Article: Angiography of hepatic vascular malformations associated with hereditary hemorrhagic telangiectasia.

  Manabu Hashimoto, Etuko Tate, Toshiaki Nishii, Jiro Watarai, Takanobu Shioya, Robert I White
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  ABSTRACT: To describe the angiographic features of hepatic involvement in hereditary hemorrhagic telangiectasia (HHT), particularly the presence of portovenous shunts. We reviewed the angiographic findings of seven patients with HHT. The patients comprised three women and four men with a mean age of 51 years. Intrahepatic telangiectasias were found in all seven patients and shunts between three vascular channels were found in six of seven patients. In the four patients who had portovenous shunts combined with arterioportal shunts, the portovenous shunts were large. Three patients had no portovenous shunts. Two of these patients had arteriovenous shunts, and one had no shunt. The mean age (69 years) of the patients with portovenous shunts was older than those without portovenous shunts (26 years). Hepatic vascular lesions in HHT are varied, ranging from telangiectasias to large shunts between three vascular channels. In an advanced stage of involvement, large portovenous shunts are present.
  CardioVascular and Interventional Radiology 26(2):177-80. · 2.09 Impact Factor