著者

小倉 明夫 東田 満治 山崎 勝 井上 博志

出版者

公益社団法人日本放射線技術学会

雑誌

日本放射線技術學會雜誌 (ISSN:03694305)

巻号頁・発行日

vol.54, no.6, pp.778-783, 1998-06-20

被引用文献数

10

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To calculate the contrast-to-noise ratio (CNR) on magnetic resonance images, an equation selected to match each study is commonly used. The CNR values calculated using these equations may have their own characteristics. Therefore, the characteristics of four commonly calculated CNRs were evaluated in comparison with signal detectability. For the calculation of CNR, a phantom with five different solutions of CuSO_4 was imaged using various scan sequences with different TR and NEX. These images, which had different levels of noise and contrast, were measured for averaged signal intensity and standard deviation of noise in the same ROIs (regions of interest). To define signal detectability, Burger's phantom soaked in the CuSO_4 solution was imaged with the same pulse sequences used to evaluate CNR. Burger's phantom images were evaluated by five observers with a 50% confidence level. The characteristics of each CNR valuewere evaluated by correlating them with signal detectability. The results showed that some calculated CNRs indicated the noise element, but contrast element. From the point of view of signal detectability, the equation using the average of local variance and global variance with respect to coarse pixels was superior to others.

著者

山崎 勝 東田 満治 井上 博志 林 浩二 小倉 明夫 大竹野 浩史 本郷 隆治

出版者

公益社団法人日本放射線技術学会

雑誌

日本放射線技術學會雜誌 (ISSN:03694305)

巻号頁・発行日

vol.53, no.1, 1997-01-20

被引用文献数

3