Abstract
The relationship between the number of signals averaged, slice thickness, and image quality in a magnetic resonance imaging system were assessed using the relative efficiency of transmission, η, and the conditioal entropy, Hx(Y), using the enropy method. The value of η is the measurement related to both contrast and noise of the images. Hx(Y) represents the noise component. The value of η increased in form of a S curve as the number of signals averaged was increased.
By contrast, the relationship between the slice thickness and the value of η was approximatcly linear. Also, the value of Hx(Y) decreased as the number of signals averaged and the slice thickness were increased.
The evaluation of image quality by η agreed well with visual observation. Thus, η and Hx(Y) were effective for the evaluation of magnetic resonance images.
