Rapid multislice T₁ mapping of mouse myocardium: Application to quantification of manganese uptake in α‐Dystrobrevin knockout mice

Abstract

Purpose The aim of this study was to develop a rapid, multi-slice cardiac T1 mapping method in mice, and to apply the method to quantify manganese (Mn2+) uptake in a mouse model with altered Ca2+ channel activity. Methods An ECG-triggered multi-slice saturation-recovery Look-Locker method was developed and validated both in vitro and in vivo. A two-dose study was performed to investigate the kinetics of T1 shortening, Mn2+ relaxivity in myocardium, and the impact of Mn2+ on cardiac function. The sensitivity of Mn2+-enhanced MRI in detecting subtle changes in altered Ca2+ channel activity was evaluated in a mouse model with α-dystrobrevin knockout. Results Validation studies showed strong agreement between the current method and an established method. High Mn2+ dose led to significantly accelerated T1 shortening. Heart rate decreased during Mn2+ infusion, while ejection ratio increased slightly at the end of imaging protocol. No statistical difference in cardiac function was detected between the two dose groups. Mice with α-dystrobrevin-knockout showed enhanced Mn2+ uptake in vivo. In vitro patch-clamp study showed increased Ca2+ channel activity. Conclusion The saturation-recovery method provides rapid T1 mapping in mouse hearts, which allowed sensitive detection of subtle changes in Mn2+ uptake in α-dystrobrevin-knockout mice.

Targeted Contrast Agent Specific to an Oncoprotein in Tumor Microenvironment with the Potential for Detection and Risk Stratification of Prostate Cancer with MRI

“…In this study, a Look-Locker sequence with spiral trajectory was adopted for fast T 1 mapping 33 . This sequence shortened the acquisition time to about 3 min 44 s using both Look-Locker sequence and M 0 determination.…”

“…Cartesian MRSLL images were also acquired as a validation of spiral MRSLL method. Center 64 k-space lines were acquired in Cartesian method as described previously 33 . Other acquisition parameters were the same as spiral MRSLL.…”

High field magnetic resonance imaging of rodents in cardiovascular research

“…Various applications have been studied: quantification of infarct size [24,39,168], identification of potentially salvageable myocardium [168] and evaluation of monocyte and macrophage spatiotemporal kinetics [107] in the vicinity of a myocardial infarction site, quantification of focal and diffuse fibrosis [138], or detection of changes in Ca 2? channels activity in combination with MEMRI [8,77,168,169]. T1 mapping can also provide valuable information on the pharmacology of contrast agents, and as mentioned earlier, quantitative T1 measurements are essential for perfusion studies based on the ASL technique.…”

“…T1-mapping is commonly acquired with a sequence based on the look-locker method although some authors described SNAPSHOT-FLASH Inversion Recovery (SNAP-IR) [24,124] or variable flip angle [39] strategies for the acquisition. In mouse, the acquisition is mainly made in combination with a contrast agent, gadolinium [24,39,138] or manganese [8,77,87,88,168,169]. Up to now, the technique has been successfully applied to murine models of myocardial infarction [24,39,168], cardiac hypertrophy [8,138] and dystrophinopathy [77].…”

“…In mouse, the acquisition is mainly made in combination with a contrast agent, gadolinium [24,39,138] or manganese [8,77,87,88,168,169]. Up to now, the technique has been successfully applied to murine models of myocardial infarction [24,39,168], cardiac hypertrophy [8,138] and dystrophinopathy [77]. Various applications have been studied: quantification of infarct size [24,39,168], identification of potentially salvageable myocardium [168] and evaluation of monocyte and macrophage spatiotemporal kinetics [107] in the vicinity of a myocardial infarction site, quantification of focal and diffuse fibrosis [138], or detection of changes in Ca 2?…”