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論文
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上田, 優 ; 宮地, 利明 ; 澤, 健太郎 ; 笠井, 治昌 ; 川野, 誠 ; 原, 眞咲 ; 芝本, 雄太 ; 大野, 直樹
概要:
金沢大学医薬保健研究域保健学系<br />The purpose of our study is to evaluate restricted diffusion of the water molecules caused by the t
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rabecular bone structure of the vertebra using a phantom. On a 1.5-T MRI, single shot diffusion echo planar imaging was used with b factors of 0, 500, and 1000s/mm2, effective TE of 80 ms, and TR of 2000ms. We determined ADC values with an original phantom, which consists of sponges with different space diameters and dry vertebral bone into the container filled with pure water We assessed the effects of values (0, 500, 1000s/mm2) and acquisition matrix (64×64, 128×128, 256×256) . ADC of the sponge increased as space diameter due to change in restricted diffusion of the water molecules, and was the same level of the dry vertebral bone. Moreover, ADC varied with b values and matrix sizes. Our original phantom enables to analyze restricted diffusion, and ADC is affected by the trabecular bone structure.
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大野, 直樹 ; 宮地, 利明 ; 間瀬, 光人 ; 笠井, 治昌 ; 菅, 博人 ; 朝日, 美幸 ; 川野, 誠 ; 原, 眞咲 ; 芝本, 雄太 ; 上田, 優
概要:
金沢大学附属病院放射線部<br />We evaluated regional apparent diffusion coefficient (ADC) change of the brain during the cardiac cycl
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e (ΔADC) . On a 1.5-T MRI, ECG-triggered single-shot diffusion echo planar imaging was used with sensitivity encoding, half scan and rectangular FOV techniques to minimize the bulk motion such as brain pulsation, i.e., data-sampling window of 3ms. ΔADC image was calculated from maximum minus minimum ADC value of all cardiac phase images on a pixel-by-pixel basis. We determined ΔADC in regions of parietal, frontal, temporal and occipital white matters (WM) in twelve healthy volunteers. Moreover, we assessed influences of scan parameters on ΔADC. ΔADC was affected by b-values, but unaffected by voxel size. There was no significant correlation between ΔADC and ADC. The ΔADC values in parietal WM at centrum semiovale level were significantly higher than those in temporal WM at basal ganglia level, although there was no significant difference in ADC values between among WM regions. ΔADC analysis using appropriate scan parameter makes it possible to noninvasively obtain new and more detailed information on the regional brain condition.
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小野, 絵理 ; 宮地, 利明 ; 大野, 直樹 ; 笠井, 治昌 ; 原, 真咲 ; 芝本, 雄太 ; 川野, 誠 ; 朝日, 美幸
概要:
金沢大学医薬保健研究域保健学系<br />We evaluated the R2* (iron content) and fat fraction of the liver tissue simultaneously using modul
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us and real multiple gradient-echo (MRM-GRE) sequence. On a 1.5-T MRI, modulus images of 7-9 gradient-echoes were obtained by MRM-GRE sequence at a time. A real part of the first echo image was also reconstructed to differentiate below and above the 50 percent fat fraction. The fat fraction and R2* were obtained from the parameters of a theoretically fitted formula with each echo signal. R2* and fat fraction were measured with MRM-GRE in the phantom and the liver in normal volunteers (n=6) and patients with fatty liver (n=4) . MRI-derived fat fraction of the phantom was in good agreement with the actual value, and R2* of the phantom showed a strongly positive correlation with the actual iron content. MRI-derived fat fraction in fatty liver was significantly higher than that in the normal volunteers. However, no significant difference in R2* was found between fatty liver and normal volunteers. These results show that the MRM-GRE enables to differentiate the causes of signal reduction whether increasing R2*or increasing fat fraction. The MRM-GRE method makes it possible to simply and accurately assess the fat content and the iron content.
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論文
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上田, 優 ; 宮地, 利明 ; 澤, 健太郎 ; 笠井, 治昌 ; 川野, 誠 ; 原, 眞咲 ; 芝本, 雄太 ; 大野, 直樹
概要:
The purpose of our study is to evaluate restricted diffusion of the water molecules caused by the trabecular bone struct
…
ure of the vertebra using a phantom. On a 1.5-T MRI, single shot diffusion echo planar imaging was used with b factors of 0, 500, and 1000s/mm2, effective TE of 80 ms, and TR of 2000ms. We determined ADC values with an original phantom, which consists of sponges with different space diameters and dry vertebral bone into the container filled with pure water We assessed the effects of values (0, 500, 1000s/mm2) and acquisition matrix (64×64, 128×128, 256×256) . ADC of the sponge increased as space diameter due to change in restricted diffusion of the water molecules, and was the same level of the dry vertebral bone. Moreover, ADC varied with b values and matrix sizes. Our original phantom enables to analyze restricted diffusion, and ADC is affected by the trabecular bone structure.
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