[Usefulness of phase-sensitive inversion recovery in delayed enhanced cardiac MRI].

BACKGROUND Delayed-enhancement MRI is a technique that has significant clinical usefulness, particularly for myocardial viability determination in ischemic heart disease. Delayed enhanced images have been acquired by using the inversion recovery(IR)method. It is necessary for the IR method to select optimal inversion time(TI). Recently, the phase-sensitive inversion recovery(PSIR)method has been developed to detect Gd-DTPA enhanced myocardium. PURPOSE To compare the IR method with the PSIR method by acquiring Gd-DTPA solution phantoms A(0.05 mmol/l)and B(0.04 mmol/l)in various parameters. METHOD Images were acquired using a turbo-fast low angle shot(t-flash)sequence in each method. RESULTS The null point of signal intensity(SI)shortened as the flip angle(FA)and segments increased in the IR method. Excess segments also caused the duration of breath holding to be extended. The IR method might cause reversed SI between normal and Gd-DTPA enhanced myocardium if the optimal TI was not carefully selected. On the other hand, PSIR had no problem in obtaining phase-sensitive images that were converted into positive SI keeping inverse longitudinal magnetization. The PSIR method avoided the need to select optimal TI and loss of contrast. CONCLUSION The PSIR method was a useful sequence for delayed-enhancement MRI to detect Gd-DTPA enhanced myocardium.