Ichiro Tani

St. Marianna University School of Medicine, Yokohama-shi, Kanagawa-ken, Japan

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Publications (5)7.24 Total impact

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    ABSTRACT: LEARNING OBJECTIVES 1) To describe characteristic clinicopathological behavior of liver metastasis with rare variant of primary malignancy. 2) To review CT and MR imaging findings of metastatic liver tumor from rare primary malignancy. ABSTRACT Metastatic liver tumor is one of the most common nodular hepatic lesions. The majority of metastatic liver tumors are arised from primary carcinoma of colon, breast, lung, pancreas, and stomach. CT and MR imaging findings of these common metastatic lesions are usually non-specific, but metastatic liver tumors from uncommon primary site sometimes reveal unusual CT and MR imaging findings due to unique pathologies. This exhibit focuses on clinical manifestation, pathological and imaging features of rare metastatic liver tumors. We illustrate primitive neuroectodermal tumor (PNET), carcinoid, malignant lymphoma, laryngeal cancer, uterine cancer, leiomyosarcoma, liposarcoma, small intestinal cancer, melanoma, gastrointestinal stromal tumor, and melanoma.
    Radiological Society of North America 2005 Scientific Assembly and Annual Meeting; 11/2005
  • Journal of Nippon Medical School 11/2002; 69(5):471-5.
  • American Journal of Roentgenology 06/2002; 178(5):1087-91. · 2.90 Impact Factor
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    ABSTRACT: The purpose of this study was to evaluate the CT findings of rupture of hepatocellular carcinoma (HCC) in the caudate lobe of the liver. The CT scans of five cases of rupture of HCC in the caudate lobe of the liver were retrospectively reviewed and correlated with clinical records. All cases showed exophytic tumors in the caudate lobe of the liver and high-attenuation hematomas in the lesser sac on CT. A lesser sac hematoma may be a sentinel clot sign of rupture of HCC in the caudate lobe.
    European Radiology 01/2001; 11(3):422-426. · 4.34 Impact Factor
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    ABSTRACT: Introduction Although the lungs have little solid component or protons, the organ has a lot of vessels and vascular networks which contains a large mount of pulmonary blood flow. Therefore, MR signal intensity of the lung should be mainly depend on the blood in the pulmonary vessels. However, pulmonary blood flow changes with cardiac beat, then the intensity of the blood in the pulmonary vessels should not be constant during the cardiac cycle. The purpose of this study is to demonstrate the signal difference of lung between diastolic phase and systolic phase and to introduce new perfusion weighted image of the lung without contrast material. Methods Five healthy subjects (three men and two women, 25-34 years old) without a history of chest disease volunteers to be examined under our new technique. All studies were performed using a 1.5-T VISART/EX MR system (Toshiba Corporation, Tokyo, Japan). Before acquisition of the 3D data set with respiratory gating, an EKG prep sequence was used for optimization of delay times for systolic and diastolic phases. Then, two fast imaging sequence were obtained by a one-shot 3D super fast spin-echo method with different ECG prep timings (systolic phase and diastolic phase). The imaging parameters were: TR/TE/TI, 2800-4100/80/190 ; NEX, 6; acquisition matrix, 256 x 256; FOV, 37-cm; and slice thickness, 5 mm. The scan time for each image was about 6 minutes. The 3D data set obtained during the systolic phase was used as a mask for subtraction from the 3D data obtained during the diastolic phase. In right lung, two ROIs were chosen: one within the ventral portion of the lung, and one corresponding region within the dorsal portion of the lung. The signal intensity of each ROI was measured and compared between diastolic images and systolic images. Results Both the ventral and dorsal ROIs in the diastolic phase had higher intensities than those in systolic phase (p=.041, p=.018, respectively). The dorsal ROIs had higher intensities than ventral ROIs in both diastolic and systolic phases (p=.039, p=.042, respectively). Discussion Our study revealed signal difference of the lung parenchyma between diastolic phase and systolic phase. One-shot 3D super fast spin-echo sequence in diastolic phase with respiratory gating could provide strong signal intensities from both pulmonary vessels and the lung parenchyma. The signal loss during systolic phase should result from fast flow through pulmonary vessels or flow void effect. Both diastolic and systolic phase scans showed higher signal intensity in the dorsal ROIs. The most possible cause for this dorsal-predominant intensity is difference in blood flow. A larger blood volume in regions with a gravity-dependent increase in perfusion could result in a strong intensity in the dorsal area. Subtraction image is very similar to MR pulmonary perfusion images using contrast materials. Subtraction process should suppress the intensity from the pulmonary interstitium and provide purely perfusion-weighted images without contrast materials. In conclusion, there is a significant difference of signal intensity of the lung parenchyma between diastolic phase and systolic phase. Subtraction process should provide a new perfusion weighted image of the lung without contrast material. One-shot 3D super fast spin-echo sequence with ECG and respiratory gating technique during diastolic phase reveals strong signals from both major vessels and pulmonary parenchyma. Same sequence in systolic phase shows decreased signal intensity of the lung. Subtraction image provides a perfusion weighted image of the lung without contrast material.

Publication Stats

29 Citations
7.24 Total Impact Points

Institutions

  • 2001–2002
    • St. Marianna University School of Medicine
      • Department of Radiology
      Yokohama-shi, Kanagawa-ken, Japan