Dynamic T-1 measurement using snapshot-FLASH MRI

The application of an inversion-recovery snapshot FLASH (f ast low-angled shot) imaging sequence to the dynamic measurement of monoexponential T-1 relaxation was investigated, The effect of(a) a reduction in the overall sequence repetition time, and (b) an increase of the read-pulse flip angle, on the measurement of T-1 was analyzed, The error in T-1 introduced by these factors is calculated, and a fuller analysis that takes them into account is presented, Data from a phantom are used to confirm this analysis. The magnitude of the errors is illustrated by measuring myocardial T-1 in patients with acute ischaemic heart disease during the injection of a bolus of the contrast medium gadobenate dimeglumine. Overall, there was a 10% difference between the T-1 values when the approximate and exact solutions were used; this was statistically significant, However, the difference was on average 25% for patients with a high heart rate (because of the shorter sequence-repetition time) in areas of infarcted myocardium (because of the longer T-1). (C) 1997 Academic Press.