Breathhold multiecho fast spin‐echo pulse sequence for accurate R 2 measurement in the heart and liver

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. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.