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Improved transverse relaxation rate measurement techniques for the assessment of hepatic and myocardial iron content
Author(s) -
Song Ruitian,
Cohen Alan R.,
Song Hee Kwon
Publication year - 2007
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.20994
Subject(s) - gradient echo , nuclear magnetic resonance , medicine , relaxation (psychology) , pulse sequence , nuclear medicine , pulse (music) , magnetic resonance imaging , physics , radiology , optics , detector
Purpose To develop and validate an optimized respiratory‐gated, gradient‐echo sampling of free induction decay and echo (GESFIDE) pulse sequence for the simultaneous measurement of R 2 , R 2 *, and R 2 ′ in the liver or heart. Materials and Methods Fifteen subjects (12 thalassemia patients and three normal volunteers) were scanned using an optimized navigator‐gated GESFIDE pulse sequence for the measurement of R 2 , R 2 *, and R 2 ′ in the liver and heart. For imaging the myocardium, dark‐blood preparation was used to suppress the blood signal to improve accuracy. The results were compared with those obtained from breath‐held GESFIDE and multi‐gradient‐echo (GRE) scans. Results Good agreement between breath‐held and navigator‐gated scans was found for R 2 , R 2 *, and R 2 ′ values in the liver (slopes = 0.97–0.99, r = 0.997–0.998, P < 0.0001) and for R 2 * in the heart (slope = 1.02, r = 0.85, P < 0.0001). Both R 2 * and R 2 ′ were closely correlated to R 2 in the liver, with correlation factors of 0.998 and 0.994, respectively, but weaker correlations were observed in the heart (r = 0.72 for R 2 * vs. R 2 and r = 0.51 for R 2 ′ vs. R 2 ). Conclusion The improved sequence enables free‐breathing measurements of transverse relaxation rates of the myocardium and liver. The method precludes the need for multiple breath‐held scans and possible misregistration issues, and may prove most beneficial for imaging young children and patients who may have difficulty with prolonged or repeated breath‐holds. J. Magn. Reson. Imaging 2007;26:208–214. © 2007 Wiley‐Liss, Inc.