Precision Imaging of Cardiac Function and Infarct Scar Size: A Study with Ultrahigh-Field MRI in Acute and Chronic Porcine Models of Myocardial Infarction

Research Background

Cardiac magnetic resonance imaging (MRI) is an accurate and highly reproducible technique for assessing cardiac function and volume. In recent years, ultrahigh-field (UHF) MRI has been committed to enhancing signal-to-noise ratio (SNR) and image resolution. 7T MRI may improve the accuracy of clinical parameters, allowing for early detection of functional abnormalities and assessment of treatment responses. However, existing research on precise measurements of cardiac function and infarct scar size in large animal models such as pigs is limited, and traditional cardiac MRI systems lack in image quality and temporal resolution.

The rationale for this study lies in the fact that changes in cardiac pathology lead to alterations in important physiological indicators, such as the ejection fraction (EF) and myocardial mass. Especially after Myocardial Infarction (MI), these changes are closely related to the long-term risk assessment of patients. Therefore, developing an imaging technology that provides greater accuracy, reliability, and repeatability has significant scientific value and clinical application prospects.

Source of Research

This study was co-authored by David Lohr, Alena Kollmann, Maya Bille and others. The authors are affiliated with the Department of Molecular and Cellular Imaging at the University Hospital Würzburg, Germany. The paper was published in Communications Medicine with DOI 10.1038/s43856-024-00559-y.

Research Details

The study scanned 7 female German Landrace pigs at three time points before and after myocardial infarction (3-4 days, 7-10 days, and approximately 60 days). The experiment used a whole-body 7T system and three radio frequency (RF) coils developed and manufactured in the laboratory to accommodate the growth of the animals.

Using specific RF hardware and 7T MRI for longitudinal studies in pig models of acute and chronic infarction, consistent blood tissue contrast and high SNR were provided to measure cardiac function and ejection fraction (COV_intra-observer: 2%, COV_inter-observer: 3.8%) and infarct size (COV_intra-observer: 8.4%, COV_inter-observer: 3.8%).

Experimental Methods

The research team utilized 7T MRI and three RF coils reasonably designed for different animal weights. Image data was analyzed using a manual segmentation method. In addition, late gadolinium enhancement (LGE) imaging was conducted using the contrast agent gadobutrol (Gadovist®).

Research Findings

The study demonstrated the feasibility of assessing cardiac function and measuring infarct area size using 7T MRI under significant changes in animal body weight. Results showed that compared to traditional 1.5T or 3T MRI, the COV of 7T MRI was significantly reduced, thereby providing higher precision and consistency in measuring ejection fraction and infarct size.

Research Conclusions and Significance

The study concluded that while manual segmentation is required to achieve optimal results, this research has defined advanced procedures for conducting large animal cardiac studies under 7T. The scientific and application values provided by ultrahigh-field MRI include earlier detection of functional abnormalities, assessment of treatment responses, and a deeper understanding of large animal model studies.

Research Features

This research highlights the precision problem solving in cardiac function and infarct scar assessment, reflecting innovative approaches to large animal research methods in the field of cardiac MRI, as well as the special instrument design for the adaptability of experimental animal growth.

Combined with the overview of this study, this work provides valuable data for the field of cardiac MRI, laying the groundwork for further improvements in diagnostic accuracy and precision of therapeutic interventions.