title: Correction with blood T1 is essential when measuring post-contrast myocardial T1 value in patients with acute myocardial infarction.
abstract: BACKGROUND
  Post-contrast T1 mapping by modified Look-Locker inversion recovery (MOLLI) sequence has been introduced as a promising means to assess an expansion of the extra-cellular space. However, T1 value in the myocardium can be affected by scanning time after bolus contrast injection. In this study, we investigated the changes of the T1 values according to multiple slicing over scanning time at 15 minutes after contrast injection and usefulness of blood T1 correction.
  
  
  METHODS
  Eighteen reperfused acute myocardial infarction (AMI) patients, 13 cardiomyopathy patients and 8 healthy volunteers underwent cardiovascular magnetic resonance with 15 minute-post contrast MOLLI to generate T1 maps. In 10 cardiomyopathy cases, pre- and post-contrast MOLLI techniques were performed to generate extracellular volume fraction (Ve). Six slices of T1 maps according to the left ventricular (LV) short axis, from apex to base, were consecutively obtained. Each T1 value was measured in the whole myocardium, infarcted myocardium, non-infarcted myocardium and LV blood cavity.
  
  
  RESULTS
  The mean T1 value of infarcted myocardium was significantly lower than that of non-infarcted myocardium (425.4 ± 68.1 ms vs. 540.5 ± 88.0 ms, respectively, p < 0.001). T1 values of non-infarcted myocardium increased significantly from apex to base (from 523.1 ± 99.5 ms to 561.1 ± 81.1 ms, p = 0.001), and were accompanied by a similar increase in blood T1 value in LV cavity (from 442.1 ± 120.7 ms to 456.8 ± 97.5 ms, p < 0.001) over time. This phenomenon was applied to both left anterior descending (LAD) territory (from 545.1 ± 74.5 ms to 575.7 ± 84.0 ms, p < 0.001) and non-LAD territory AMI cases (from 501.2 ± 124.5 ms to 549.5 ± 81.3 ms, p < 0.001). It was similarly applied to cardiomyopathy patients and healthy volunteers. After the myocardial T1 values, however, were adjusted by the blood T1 values, they were consistent throughout the slices from apex to base (from 1.17 ± 0.18 to 1.25 ± 0.13, p > 0.05). The Ve did not show significant differences from apical to basal slices.
  
  
  CONCLUSIONS
  Post-contrast myocardial T1 corrected by blood T1 or Ve, provide more stable measurement of degree of fibrosis in non-infarcted myocardium in short- axis multiple slicing.
authors: Division of Cardiology, Heart Center, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea. choi0928@yuhs.ac
authors: Eui-Young
authors: EY
authors: Choi
authors: Sung Ho
authors: SH
authors: Hwang
authors: Young Won
authors: YW
authors: Yoon
authors: Chul Hwan
authors: CH
authors: Park
authors: Mun Young
authors: MY
authors: Paek
authors: Andreas
authors: A
authors: Greiser
authors: Hyemoon
authors: H
authors: Chung
authors: Ji-Hyun
authors: JH
authors: Yoon
authors: Jong-Youn
authors: JY
authors: Kim
authors: Pil-Ki
authors: PK
authors: Min
authors: Byoung Kwon
authors: BK
authors: Lee
authors: Bum-Kee
authors: BK
authors: Hong
authors: Se-Joong
authors: SJ
authors: Rim
authors: Hyuck Moon
authors: HM
authors: Kwon
authors: Tae Hoon
authors: TH
authors: Kim
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D009202:Cardiomyopathies / Q000175:diagnosis / Q000473:pathology; D016022:Case-Control Studies; D003287:Contrast Media; D005260:Female; D005355:Fibrosis; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008536:Meglumine; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D009206:Myocardium / Q000473:pathology*; D009942:Organometallic Compounds; D011237:Predictive Value of Tests; D013997:Time Factors; D016277:Ventricular Function, Left
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; D008536:Meglumine; C072417:gadoterate meglumine