論文

• Comparison of Brain Tumor Contrast-enhancement on T1-CUBE and 3D-SPGR Images.
  Mungunkhuyag Majigsuren, Takashi Abe, Teruyoshi Kageji, Kenji Matsuzaki, Mayumi Takeuchi, Seiji Iwamoto, Yoichi Otomi, Naoto Uyama, Shinji Nagahiro, Masafumi Harada
  Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine, 15, 1, 34, 40, 2016年, ［国内誌］
  英語, 研究論文（学術雑誌）, PURPOSE: T1-Cube (GE HealthCare) is a relatively new 3-dimensional (3D) fast spin-echo (FSE)-based magnetic resonance (MR) imaging sequence that uses a variable flip angle to acquire gap-free volume scans. We compared the gadolinium enhancement characteristics of a heterogeneous population of brain tumors imaged by T1-Cube and then 3D fast spoiled gradient recall acquisition in steady state (3D FSPGR) 3-tesla MR imaging to identify the superior modality for specific diagnostic purposes. METHODS: We examined 61 lesions from 32 patients using the 2 sequences after administration of gadopentetic acid (Gd-DTPA; 0.1 mmol/kg). Two neuroradiologists independently measured each lesion twice using a region-of-interest (ROI) method. We measured the contrast-to-noise ratio (CNR), the difference in signal intensity (SI) between the tumor and normal white matter relative to the standard deviation (SD) of the SI within the lesion, for both post-contrast 3D FSPGR and post-contrast T1-Cube images of the same tumor and compared modality-specific CNRs for all tumors and in subgroups defined by tumor size, enhancement ratio, and histopathology. RESULTS: The mean CNR was significantly higher on T1-Cube images than 3D FSPGR images for the total tumor population (1.85 ± 0.97 versus 1.12 ± 1.05, P < 0.01) and the histologic types, i.e., metastasis (P < 0.01) and lymphoma (P < 0.05). The difference in CNR was even larger for smaller tumors in the metastatic group (4.95 to 23.5 mm(2)) (P < 0.01). In contrast, mean CNRs did not differ between modalities for high grade glioma and meningioma. CONCLUSIONS: Gadolinium enhancement of brain tumors was generally higher when imaged by T1-Cube than 3D FSPGR, and T1-Cube with Gd enhancement may be superior to 3D FSPGR for detecting smaller metastatic tumors.
• Diagnosis of brain tumors using dynamic contrast-enhanced perfusion imaging with a short acquisition time.
  Takashi Abe, Yoshifumi Mizobuchi, Kohei Nakajima, Yoichi Otomi, Saho Irahara, Yuki Obama, Mungunkhuyag Majigsuren, Delgerdalai Khashbat, Teruyoshi Kageji, Shinji Nagahiro, Masafumi Harada
  SpringerPlus, 4, 88, 88, 2015年, ［国際誌］
  英語, 研究論文（学術雑誌）, This study sought to determine the diagnostic utility of perfusion parameters derived from dynamic contrast-enhanced (DCE) perfusion MRI with a short acquisition time (approximately 3.5 min) in patients with glioma, brain metastasis, and primary CNS lymphoma (PCNSL). Twenty-six patients with 29 lesions (4 low-grade glioma, 13 high-grade glioma, 7 metastasis, and 5 PCNSL) underwent DCE-MRI in a 3 T scanner. A ROI was placed on the hotspot of each tumor in maps for volume transfer contrast K (trans) , extravascular extracellular volume V e , and fractional plasma volume V p . We analyzed differences in parameters between tumors using the Mann-Whitney U test. We calculated sensitivity and specificity using receiver operating characteristics analysis. Mean K (trans) values of LGG, HGG, metastasis and PCNSL were 0.034, 0.31, 0.38, 0.44, respectively. Mean Ve values of each tumors was 0.036, 0.57, 0.47, 0.96, and mean Vp value of each tumors was 0.070, 0.086, 0.26, 0.17, respectively. Compared with other tumor types, low-grade glioma showed lower K (trans) (P < 0.01, sensitivity = 88%, specificity = 100%) and lower V e (P < 0.01, sensitivity = 96%, specificity = 100%). PCNSL showed higher V e (P < 0.01, sensitivity = 100%, specificity = 88%), but the other perfusion parameters overlapped with those of different histology. Kinetic parameters derived from DCE-MRI with short acquisition time provide useful information for the differential diagnosis of brain tumors.
• Clinical Significance of Discrepancy between Arterial Spin Labeling Images and Contrast-enhanced Images in the Diagnosis of Brain Tumors.
  Takashi Abe, Yoshifumi Mizobuchi, Wataru Sako, Saho Irahara, Yoichi Otomi, Yuki Obama, Kohei Nakajima, Delgerdalai Khashbat, Mungunkhuyag Majigsuren, Teruyoshi Kageji, Shinji Nagahiro, Masafumi Harada
  Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine, 14, 4, 313, 9, 2015年, ［国内誌］
  英語, 研究論文（学術雑誌）, PURPOSE: In the imaging of intra-axial brain tumors, we sometimes found areas of high signal intensity around the enhanced tumor lesions on arterial spin labeling (ASL) magnetic resonance (MR) imaging. We undertook this study to investigate the relationship between high signal intensity on ASL imaging outside the area of contrast enhancement (CE) and histological diagnosis of intra-axial brain tumors. METHODS: We examined images from 28 consecutive patients with intra-axial brain tumors who underwent ASL and CE MR imaging-three with low grade glioma (LGG), 13 with high grade glioma (HGG), six with metastasis, and six with primary central nervous system lymphoma (PCNSL)-and divided imaging findings into an "ASL dominant" group when hyperintensity on ASL was found outside the CE area and a "CE dominant" group when hyperintensity on ASL was not found outside the area of enhancement. We then analyzed the relationship between imaging findings and the histological diagnosis of the tumors. RESULTS: Four cases were excluded because of poor quality of ASL images, 7 cases were classified as ASL dominant, and 17 cases were classified as CE dominant. The histological diagnoses of ASL dominant cases were LGG in 3 cases, HGG in 3 cases, and PCNSL in one case. Those of CE dominant cases were HGG in 10 cases, metastasis in 5 cases, and PCNSL in 2 cases. All cases with brain metastasis were classified as CE dominant. CONCLUSION: The high signal intensity outside the area of contrast enhancement is probably caused by increased perfusion or vascular proliferation, which indicates the presence of glioma or PCNSL and not metastasis. This finding indicates a new utility for ASL images in the diagnosis of brain tumors as a supplement to the conventional measurement of perfusion obtained from ASL images.
• Longitudinal monitoring with multiple MR techniques in a case of progressive multifocal leukoencephalopathy associated with multiple myeloma.
  Majigsuren Mungunkhuyag, Masafumi Harada, Takashi Abe, Koji Fujita, Naoko Matsui, Ryuji Kaji
  Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine, 13, 1, 55, 9, 2014年, ［国内誌］
  英語, 研究論文（学術雑誌）, Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the brain caused by the JC virus in immunocompromised patients. We report characteristic features of proton MR spectroscopy, 3-dimensional pseudo-continuous arterial spin labeling imaging, and diffusion tensor imaging in a 53-year-old patient with PML. The utility of multi-modal magnetic resonance techniques for longitudinal monitoring was indicated by their reevaluation over time and consideration of their relation to prognosis.