title: Native myocardial longitudinal (T1 ) relaxation time: Regional, age, and sex associations in the healthy adult heart.
abstract: To use magnetic resonance imaging (MRI) at two field strengths to assess healthy adults' regional myocardial noncontrast (native) T1 relaxation time distribution, and global myocardial native T1 between sexes and across age groups.
  
  
  
  In all, 84 healthy volunteers underwent MRI at 1.5T and 3.0T. T1 maps were acquired in three left ventricular short axis slices using an optimized modified Look-Locker inversion recovery investigational prototype sequence. T1 measurements in msec were calculated from 16 regions-of-interest, and a global T1 value from all evaluable segments per subject. Associations were assessed with a multivariate linear regression model.
  
  
  
  In total, 1297 (96.5%) segments were evaluable at 1.5T and 1263 (94.0%) segments at 3.0T. Native T1 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 T1 decreased with increasing age in females but not in males. Among lowest age tertile (<33 years) global native T1 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 T1 to age (P = 0.002) and sex (P < 0.001) was independent of field strength and body size.
  
  
  
  In healthy adults, native T1 values are highest in the ventricular septum. Global native T1 was inversely associated with age in women, but not in men. J. Magn. Reson. Imaging 2016;44:541-548.
authors.affiliation: BHF Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow, UK.
authors.forename: Samuli M O
authors.initials: SM
authors.lastname: Rauhalammi
authors.affiliation: BHF Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow, UK.|West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Glasgow, UK.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Mangion
authors.affiliation: Department of Clinical Physics, Queen Elizabeth University Hospital, Glasgow, Glasgow, UK.
authors.forename: Pauline Hall
authors.initials: PH
authors.lastname: Barrientos
authors.affiliation: BHF Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow, UK.|West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Glasgow, UK.
authors.forename: David J A
authors.initials: DJ
authors.lastname: Carrick
authors.affiliation: BHF Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow, UK.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Clerfond
authors.affiliation: BHF Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow, UK.
authors.forename: John
authors.initials: J
authors.lastname: McClure
authors.affiliation: BHF Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow, UK.|Department of Clinical Physics, Queen Elizabeth University Hospital, Glasgow, Glasgow, UK.
authors.forename: Christie
authors.initials: C
authors.lastname: McComb
authors.affiliation: BHF Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow, UK.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Radjenovic
authors.affiliation: BHF Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow, UK.|West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Glasgow, UK.
authors.forename: Colin
authors.initials: C
authors.lastname: Berry
mesh_terms: D000375:Aging / Q000473:pathology / Q000502:physiology*; D057791:Cardiac Imaging Techniques / Q000379:methods*; D005260:Female; D006352:Heart Ventricles / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012727:Sex Characteristics; D016277:Ventricular Function, Left / Q000502:physiology*
keywords: T1 mapping; healthy volunteer; longitudinal relaxation time; myocardium; native T1