心臓遅延造影ＭＲＩにおける安静呼吸下Ｔｈｒｅｅ−ｄｉｍｅｎｓｉｏｎａｌ Ｐｈａｓｅ−ｓｅｎｓｉｔｉｖｅ Ｉｎｖｅｒｓｉｏｎ Ｒｅｃｏｖｅｒｙ（３Ｄ ＰＳＩＲ）法の基礎検討

Abstract

We studied imaging parameters for the three-dimensional phase-sensitive inversion recovery by a late gadolinium enhancement (3D PSIR) method. In the 3D PSIR method using a 1.5 Tesla MRI system and a polyvinyl alcohol (PVA) gel phantom, we evaluated the relation of the signal intensity at multiple inversion times (TI), 100-500 ms; flip angles (FA), 15-35°; and segments, 20-45. In 30 patients with chronic myocardial infarction, we measured and compared the late gadolinium enhancement (LGE) image area of ratio for each of 3 sections on both 3D LGE images by a non-breath hold and two-dimensional inversion recovery (2D IR) method non-breath hold. In the 3D PSIR method, we recognized the signal intensity to make the width of step, maximum, and we recognized that the TI range, to keep the effective signal intensity difference constant, was limited on each phantom. The more this TI range decreased the bigger the difference in the FA and signal intensity. The set-up range of TI for the segment number remained the same. In the clinical setting, we recognized a good correlation between the 3D PSIR method (TI 300 ms, FA 20°) and the IR method (r=0.905, p<0.001). The imaging parameter that can be used in the clinical setting with the 3D PSIR method is FA 20° TI 200-300 ms, with the segment number adjusted by the cardiac cycle.