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Objective: In a proof-of-concept study, to quantify myocardial viability in patients with acute myocardial infarction using manganese-enhanced MRI (MEMRI), a measure of intracellular calcium handling.
Methods: Healthy volunteers (n=20) and patients with ST-elevation myocardial infarction (n=20) underwent late gadolinium enhancement (LGE) using gadobutrol and MEMRI using manganese dipyridoxyl diphosphate. Patients were scanned ≤7 days after reperfusion and rescanned after 3 months. Differential manganese uptake was described using a two-compartment model.
Results: After manganese administration, healthy control and remote non-infarcted myocardium showed a sustained 25% reduction in T1 values (mean reductions, 288±34 and 281±12 ms). Infarcted myocardium demonstrated less T1 shortening than healthy control or remote myocardium (1157±74 vs 859±36 and 835±28 ms; both p<0.0001) with intermediate T1 values (1007±31 ms) in peri-infarct regions. Compared with LGE, MEMRI was more sensitive in detecting dysfunctional myocardium (dysfunctional fraction 40.5±11.9 vs 34.9%±13.9%; p=0.02) and tracked more closely with abnormal wall motion (r=0.72 vs 0.55; p<0.0001). Kinetic modelling showed reduced myocardial manganese influx between remote, peri-infarct and infarct regions, enabling absolute discrimination of infarcted myocardium. After 3 months, manganese uptake increased in peri-infarct regions (16.5±3.5 vs 22.8±3.5 mL/100 g/min, p<0.0001), but not the remote (23.3±2.8 vs 23.0±3.2 mL/100 g/min, p=0.8) or infarcted (11.5±3.7 vs 14.0±1.2 mL/100 g/min, p>0.1) myocardium.
Conclusions: Through visualisation of intracellular calcium handling, MEMRI accurately differentiates infarcted, stunned and viable myocardium, and correlates with myocardial dysfunction better than LGE. MEMRI holds major promise in directly assessing myocardial viability, function and calcium handling across a range of cardiac diseases.
Trial Registration Numbers: NCT03607669; EudraCT number 2016-003782-25.
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http://dx.doi.org/10.1136/openhrt-2021-001646 | DOI Listing |
Behav Brain Res
August 2025
Oral Physiology, Department of Oral Functional Science, Division of Oral Medical Science, Faculty of Dental Medicine and Graduate School of Dental Medicine, Hokkaido University, Japan.
The basolateral amygdala (BLA) plays a critical role in aversive learning and decision‑making, yet its specific contribution to the expression of conditioned taste aversion (CTA) remains incompletely understood. Here, we examined how transient chemogenetic inhibition of the BLA influences licking microstructure and approach-avoidance behavior toward a conditioned saccharin solution. Male C57BL/6 mice received bilateral BLA injections of AAV8‑hSyn‑hM4Di‑mCherry (experimental) or AAV8‑hSyn‑mCherry (control).
View Article and Find Full Text PDFMagn Reson Imaging
November 2025
Department of Radiology, School of Medicine, Kyungpook National University, Daegu, Republic of Korea. Electronic address:
Background: Manganese-enhanced MRI (MEMRI) visualizes neuronal activity via manganese uptake. While intravitreal MnCl₂ injection is effective, it is invasive and carries toxicity risks. This study aimed to evaluate a noninvasive topical MnCl₂ approach for detecting functional activation in the rat visual pathway in response to color-specific light stimuli.
View Article and Find Full Text PDFbioRxiv
June 2025
Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI.
Purpose: Investigation of the electromagnetic perceptive gene (EPG) protein and garnering evidence to suggest its use as a magnetogenetic tool for neuromodulation. Activation of EPG by electromagnetic field increases intracellular calcium levels, thus, we aimed to determine whether EPG influences the analogous manganese ion. This work yields potential for manganese-enhanced MRI (MEMRI) to be used to monitor EPG acting as a neuromodulator.
View Article and Find Full Text PDFbioRxiv
July 2025
Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110, USA.
Inter-areal communication is crucial for brain function. Given the largely contralateral organization of the brain, bimanual coordination likely involves interactions across the two cerebral hemispheres for motor planning and execution. The parietal reach region (PRR) is an early node in the sensorimotor transformation stream.
View Article and Find Full Text PDFPhysiol Rep
July 2025
Biomedical MRI, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium.
Early assessment of myocardial viability post-ischemia is crucial to mitigate adverse remodeling and optimize therapy. Current noninvasive methods like late gadolinium enhancement (LGE) MRI may overestimate infarct size. Manganese-enhanced MRI (MEMRI) emerged as a promising alternative, offering greater specificity in assessing myocardial damage.
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