Elsevier

JACC: Cardiovascular Imaging

Volume 8, Issue 9, September 2015, Pages 1019-1030
JACC: Cardiovascular Imaging

Original Research
Native T1 Mapping by 3-T CMR Imaging for Characterization of Chronic Myocardial Infarctions

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Abstract

Objectives

The purpose of this study was to investigate whether native T1 maps at 3-T can reliably characterize chronic myocardial infarctions (MIs) in patients with prior ST-segment elevation myocardial infarction (STEMI) or non-ST-segment elevation myocardial infarction (NSTEMI).

Background

Late gadolinium enhancement (LGE) cardiac magnetic resonance is the gold standard for characterizing chronic MIs, but it is contraindicated in patients with end-stage chronic kidney disease.

Methods

Native T1 and LGE images were acquired at 3-T in patients with prior STEMI (n = 13) and NSTEMI (n = 12) at a median of 13.6 years post-MI. Infarct location, size, and transmurality were measured using mean ± 5 SDs thresholding criterion from LGE images and T1 maps and compared against one another. Independent reviewers assessed visual conspicuity of MIs on LGE images and T1 maps.

Results

Native T1 maps and LGE images were not different for measuring infarct size (STEMI: p = 0.46; NSTEMI: p = 0.27) and transmurality (STEMI: p = 0.13; NSTEMI: p = 0.21) using thresholding criterion. Using thresholding criterion, good agreement was observed between LGE images and T1 maps for measuring infarct size (STEMI: bias = 0.6 ± 3.1%; R2 = 0.93; NSTEMI: bias = −0.4 ± 4.4%; R2 = 0.85) and transmurality (STEMI: bias = 2.0 ± 4.2%; R2 = 0.89; NSTEMI: bias = −2.7 ± 7.9%; R2 = 0.68). Sensitivity and specificity of T1 maps for detecting chronic MIs based on thresholding criterion were 89% and 98%, respectively (STEMI), and 87% and 95%, respectively (NSTEMI). Relative to LGE images, the mean visual conspicuity score for detecting chronic MIs was significantly lower for T1 maps (p < 0.001 for both cases). Median infarct-to-remote myocardium contrast-to-noise ratio was 2.5-fold higher for LGE images relative to T1 maps (p < 0.001). Sensitivity and specificity of T1 maps for visual detection were 60% and 86%, respectively (STEMI), and 64% and 91% (NSTEMI), respectively.

Conclusions

Chronic MIs in STEMI and NSTEMI patients can be reliably characterized using threshold-based detection on native T1 maps at 3-T. Visual detection of chronic MIs on native T1 maps in both patient populations has high specificity, but modest sensitivity.

Key Words

chronic myocardial infarction
native T1 mapping
viability imaging

Abbreviations and Acronyms

AHA
American Heart Association
CI
confidence interval
CMR
cardiac magnetic resonance
CNR
contrast-to-noise ratio
LGE
late gadolinium enhancement
MI
myocardial infarction
IQR
interquartile range
MOLLI
modified Look-Locker inversion recovery
NSTEMI
non–ST-segment elevation myocardial infarction
SI
signal intensity
STEMI
ST-segment elevation myocardial infarction

Cited by (0)

This work was supported, in part, by grants from the American Heart Association (13PRE17210049); the National Heart, Lung, and Blood Institute (HL091989); and the National Research Foundation of Korea (MEST No. 2012027176). Dr. Dharmakumar and Mr. Kali are coinventors on a patent pending (PCT/US14/53938) on the use of T1 mapping at 3-T for characterizing chronic myocardial infarction. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.

Drs. Kali and E.-Y. Choi contributed equally to this work.