Abstract
PurposeTo use magnetic resonance imaging (MRI) at two field strengths to assess healthy adults' regional myocardial noncontrast (native) T 1 relaxation time distribution, and global myocardial native T 1 between sexes and across age groups.Materials and MethodsIn all, 84 healthy volunteers underwent MRI at 1.5T and 3.0T. T 1 maps were acquired in three left ventricular short axis slices using an optimized modified Look–Locker inversion recovery investigational prototype sequence. T 1 measurements in msec were calculated from 16 regions‐of‐interest, and a global T 1 value from all evaluable segments per subject. Associations were assessed with a multivariate linear regression model.ResultsIn total, 1297 (96.5%) segments were evaluable at 1.5T and 1263 (94.0%) segments at 3.0T. Native T 1 was higher in septal than lateral myocardium (1.5T: 956.3 ± 44.4 vs. 939.2 ± 54.2 msec; P < 0.001; 3.0T: 1158.2 ± 45.9 vs. 1148.9 ± 56.9 msec; P = 0.012). Native T 1 decreased with increasing age in females but not in males. Among lowest age tertile (<33 years) global native T 1 was higher in females than in males at 1.5T (960.0 ± 20.3 vs. 931.5 ± 22.2 msec, respectively; P = 0.003) and 3.0T (1166.5 ± 19.7 vs. 1130.2 ± 20.6 msec; P < 0.001). No sex differences were observed in upper age tertile (≥55 years) at 1.5T (937.7 ± 25.4 vs. 934.7 ± 22.3 msec; P = 0.762) or 3.0T (1153.0 ± 30.0 vs. 1132.3 ± 23.5 msec; P = 0.056). Association of global native T 1 to age (P = 0.002) and sex (P < 0.001) was independent of field strength and body size.ConclusionIn healthy adults, native T 1 values are highest in the ventricular septum. Global native T 1 was inversely associated with age in women, but not in men. J. Magn. Reson. Imaging 2016;44:541–548.
Highlights
Proton relaxation time in vivo using parametric mapping techniques
There was a moderate correlation between the intraindividual global native T1 values measured at different field strengths (r 5 0.577; P < 0.001) (Supplementary Fig. 2)
We present information on myocardial native T1 values at 1.5T and 3.0T in 84 adults across a broad age range
Summary
Non-contrast (native) T1 reflects myocardial water content and pathology, and T1 mapping has emerging clinical utility for detection of acute myocardial infarction,[1] acute myocarditis,[2] infiltrative cardiomyopathy,[3,4] and pressure-overload hypertrophy.[5]. T1 can be measured in regions-of-interest (ROIs) in the heart.[6] T1 map acquisitions are susceptible to artifacts, especially at higher magnetic fields, making their interpretation challenging.[7] T1 values vary between scanner type and pulse sequence, and clinical guidelines recommend standardization of image acquisition and analysis.[8] Piechnik et al[9] described variation of native myocardial T1 in healthy subjects using the shortened modified Look–. They observed that native T1 was associated with sex, body size, and hematocrit, but not age. VC 2016 The Authors Journal of Magnetic Resonance Imaging published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine 1
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