keyhole率の違いによる画質への影響

抄録

The keyhole data acquisition technique, which is designed to shorten scanning time, is generally used for dynamic studies. We used a computer simulation technique to perform a quantitative examination of the effect of keyhole rate on image quality. We found that, when the keyhole rate is less than 30%, the error of pixel intensity increases. Further, the better a tissue is enhanced, the larger the error of pixel intensity. The error is most severe in geometrical images with additional defect, reaching 25% at maximum. Error arises from the discontinuity in k-space data in the phase-encoding direction. Examiners need to be careful not to set the KHR too low, especially when dynamic study is required for the evaluation of a small structure that is also expected to be well enhanced, such as the pituitary gland. In summary, we recommended a KHR of at least 40%.