Breathhold multiecho fast spin-echo pulse sequence for accurate R2 measurement in the heart and liver

Abstract

Measurement of proton transverse relaxation rates (R 2) is a generally useful means for quantitative characterization of pathological changes in tissue with a variety of clinical applications. The most widely used R 2 measurement method is the Carr-Purcell-Meiboom-Gill (CPMG) pulse sequence but its relatively long scan time requires respiratory gating for chest or body MRI, rendering this approach impractical for comprehensive assessment within a clinically-acceptable examination time. The purpose of our study was to develop a breathhold multiecho fast spin-echo (FSE) sequence for accurate measurement of R 2 in the liver and heart. Phantom experiments and studies of subjects in vivo were performed to compare the FSE data with the corresponding even-echo CPMG data. For pooled data, the R 2 measurements were strongly correlated (Pearson correlation coefficient = 0.99) and in excellent agreement (mean difference [CPMG - FSE] = 0.10 s -1; 95% limits of agreement were 1.98 and -1.78 s -1) between the two pulse sequences. © 2009 Wiley-Liss, Inc.