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

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Abstract
Measurement of proton transverse relaxation rates (R2) is a generally useful means for quantitative characterization of pathological changes in tissue with a variety of clinical applications. The most widely used R2 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 R2 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 R2 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.