1.

論文
論文
1. MRIにおけるSNRの空間周波数特性の評価
宮地, 利明 ; 藤田, 広志 ; 真田, 茂 ; 越田, 吉郎 ; 春日, 敏夫
出版情報: 医用画像情報学会雑誌 = Medical Imaging and Information Sciences.  18  pp.87-92,  2001-01-01.  医用画像情報学会 = MII: Japan Society of Medical Imaging and Information Sciences
URL: http://hdl.handle.net/2297/36644
概要: A method was developed to accurately measure signal-to-noise ratios (SNRs) in positive and negative frequencies of magnetic resonance images (MRIs). SNR2(f) was calculated from the modulation transfer function (MTF) and the Wiener … spectrum, both of which were determined with subtracted complex images at the same phantom setting. The SNR2(f)s in the conventional spin echo (SE) and Turbo SE which set effective echo time at the first echo were evaluated by changing the T2 of the phantom in the frequency and phase encode directions. SNR2s gave positive and negative spatial frequency information that was not obtained with conventional methods. In this method, the influences of image nonuniformity and unnecessary artifacts could be eliminated. Analysis of the SNR in the spatial frequency domain made it possible to obtain more detail on the image quality of MRI. 続きを見る
2.

論文
論文
2. NEQを用いたマルチスライスCTの体軸方向における画質評価
五味, 勉 ; 春日, 敏夫 ; 角谷, 眞澄 ; 宮地, 利明 ; 越田, 吉郎 ; 安藤, 隆 ; 上田, 仁 ; 佐々木, 祥之
出版情報: 医用画像情報学会雑誌 = Medical Imaging and Information Sciences.  19  pp.136-140,  2002-01-01.  医用画像情報学会 = MII: Japan Society of Medical Imaging and Information Sciences
URL: http://hdl.handle.net/2297/36647
概要: We analysed of the images generated with multi-slice CT in the longitudinal direction (Z) and assessed the noise equivalent quanta (NEQ)evaluation. Evaluation of image quality in NEQ, was possible to accuracy of reappearance in … low at high frequency characteristics. In addition, NEQ information was confirmed of usefulness in compared with Winer spectra and MTF method. Examination results suggest that the quantitative analysis in characteristics of image noise and image resolution at multi-slice CT images can provide an optimal parameter for improving quality of images in clinical data. 続きを見る
3.

論文
論文
3. パラレルイメージングプログラムの開発
今井, 広 ; 春日, 敏夫 ; 宮地, 利明 ; 笠井, 治昌 ; 川野, 誠 ; 杉山, 雅之
出版情報: 医用画像情報学会雑誌 = Medical Imaging and Information Sciences.  20  pp.27-33,  2003-01-01.  医用画像情報学会 = MII: Japan Society of Medical Imaging and Information Sciences
URL: http://hdl.handle.net/2297/36648
概要: Parallel imaging in magnetic resonance imaging (MRI) is a method to reduce the acquisition time by using phased array coils. However, there are a small number of commercial diagnostic MR imagers which could be used that method. Therefore, … we developed a parallel imaging program for sensitivity encoding (SENSE). We produced sensitivity maps calculated from phantom images which was obtained with each coil element. Next, we eliminated wrap-around artifacts by using the sensitivity maps. Parallel imaging with SENSE made it possible to achieve fast scan or remove wrap-around artifacts. 続きを見る