Fluid Attenuated Inversion Recovery Balanced Turbo Field Echo (FLAIR-B-TFE)における画像コントラストについての基礎的検討

Abstract

We have made clinical use of FLAIR-B-TFE, where an image is taken at the null point (NP) of water with the addition of inversion pulse to B-TFE, and obtained highly effective results in many areas. Changes in NP and image contrast were reviewed to optimize this sequence. Oil, water, and venous blood before and after Gd-DTPA dispensation as well as diluted (by 500/4000 times) Gd-DTPA solution were designated as the standard phantoms wherein shot intervals (SI), scan modes, k-space ordering, TFE factor, dummy pulse, and presence or absence of IR pulses were changed. What affects the NP of water most is the SI, and unless SI is long enough so that the longitudinal magnetization of water can recover to the full, NP will change. There is little difference in image contrast between the NP of water and that of blood, and a sluggish blood signal ascendance will necessitate intentional blood signal ascendance by contrast-enhancement. The signal intensity of blood after the angiographies will almost reach a plateau at an SI level of more than 2000 ms. Therefore, it is appropriate to apply SI 2000 ms, in view of the time necessary for contrast-enhancement.