Assessment of myocardial injury after reperfused infarction by T1ρ cardiovascular magnetic resonance

Abstract

BackgroundThe evolution of T1ρ and of other endogenous contrast methods (T2, T1) in the first month after reperfused myocardial infarction (MI) is uncertain. We conducted a study of reperfused MI in pigs to serially monitor T1ρ, T2 and T1 relaxation, scar size and transmurality at 1 and 4 weeks post-MI.MethodsTen Yorkshire swine underwent 90 min of occlusion of the circumflex artery and reperfusion. T1ρ, T2 and native T1 maps and late gadolinium enhanced (LGE) cardiovascular magnetic resonance (CMR) data were collected at 1 week (n = 10) and 4 weeks (n = 5). Semi-automatic FWHM (full width half maximum) thresholding was used to assess scar size and transmurality and compared to histology. Relaxation times and contrast-to-noise ratio were compared in healthy and remote myocardium at 1 and 4 weeks. Linear regression and Bland-Altman was performed to compare infarct size and transmurality.ResultsRelaxation time differences between infarcted and remote myocardial tissue were ∆T1 (infarct-remote) = 421.3 ± 108.8 (1 week) and 480.0 ± 33.2 ms (4 week), ∆T1ρ = 68.1 ± 11.6 and 74.3 ± 14.2, and ∆T2 = 51.0 ± 10.1 and 59.2 ± 11.4 ms. Contrast-to-noise ratio was CNRT1 = 7.0 ± 3.5 (1 week) and 6.9 ± 2.4 (4 week), CNRT1ρ = 12.0 ± 6.2 and 12.3 ± 3.2, and CNRT2 = 8.0 ± 3.6 and 10.3 ± 5.8. Infarct size was not significantly different for T1ρ, T1 and T2 compared to LGE (p = 0.14) and significantly decreased from 1 to 4 weeks (p < 0.01). Individual infarct size changes were ∆T1ρ = −3.8%, ∆T1 = −3.5% and ∆LGE = −2.8% from 1 – 4 weeks, but there was no observed change in infarct size for T2 or histologically.ConclusionsT1ρ was highly correlated with alterations left ventricle (LV) pathology at 1 and 4 weeks post-MI and therefore it may be a useful method endogenous contrast imaging of infarction.Electronic supplementary materialThe online version of this article (doi:10.1186/s12968-017-0332-z) contains supplementary material, which is available to authorized users.

Segmented radial cardiac MRI during arrhythmia using retrospective electrocardiogram and respiratory gating

“…Contijoch et al recently reported a retrospective self‐gated golden‐ratio CMR technique analogous to the presented ECG‐based approach. That study nicely demonstrated its use for cine imaging of subjects with premature ventricular contractions . In this study, feasibility and relative efficiency of beat‐type gating was demonstrated for more‐general imaging of sinus rhythm and atrial fibrillation as well as intermittent premature beats.…”

“…That study nicely demonstrated its use for cine imaging of subjects with premature ventricular contractions. 27,28 In this study, feasibility and relative efficiency of beat-type gating was demonstrated for more-general F I G U R E 6 Beat-type gated imaging of pacing simulated premature beats. Paced premature beats were introduced every 5 beats.…”

Myocardial Scar Delineation Using Diffusion Tensor Magnetic Resonance Tractography

“…Noncontrast magnetic resonance imaging approaches based on the measurement of myocardial relaxation rates,34, 35 magnetization transfer,36 and apparent diffusivity21 have been reported; however, with the exception of T1 mapping–based techniques, these approaches remain experimental. In addition, traditional indexes of diffusion such as MD and FA may not show large variations in fully healed chronic infarcts 20, 37…”

“…LGE magnetic resonance imaging is commonly used for the detection of myocardial infarction [1][2][3][4] ; however, many patients with cardiovascular disease cannot receive gadolinium because of impaired renal function. 14 Noncontrast magnetic resonance imaging approaches based on the measurement of myocardial relaxation rates, 34,35 magnetization transfer, 36 and apparent diffusivity 21 have been reported; however, with the exception of T1 mapping-based techniques, these approaches remain experimental. In addition, traditional indexes of diffusion such as MD and FA may not show large variations in fully healed chronic infarcts.…”

Erratum to: Assessment of myocardial injury after reperfused infarction by T1ρ cardiovascular magnetic resonance

“…In the original version of this article [1], published on 15 February 2017, the author names were incorrectly displayed.…”