Simultaneous Measurements of Heart Failure is Ideal
Heart failure (HF) is a common condition that develops after the heart becomes damaged or weakened by diseases of the heart including heart attacks and other medical conditions. Damage and recovery can be assessed on the cellular, tissue, organ or whole animal scale but these are rarely measured in concert. Ideally, recovery can be measured on long term studies of animals following the infraction with imaging techniques that monitor these scales simultaneously.
The combination of simultaneous PET and MRI present a combination of four complementary measures of heart function on multiple levels. Standard volumetric measurements of ventricle size at each phase of the heart (cine MRI) can be used to measure end-systolic and end-diastolic volumes (ESV, EDV respectively). The difference between these gives the blood volume ejected in each heart beat (SV) and the ratio of SV to EDV gives the ejection fraction (EF).
PET/MRI Measures Animal, Whole-Organ, Tissue, and Cellular Response to Myocardial Infarction
A University of Cambridge study presented data obtained using complementary techniques, including PET and MRI, for multi-modal characterization of the hearts of infarcted mice1. Mice were studied whose left anterior descending (LAD) coronary artery was occluded for 30 minutes to induce an ischemic insult with imaging being performed after 24 hours of reperfusion.
Although the protocol utilized MRI followed by PET imaging using 18F-fluorodeoxyglucose (FDG) as a direct marker of cellular viability and image co-registration in a sequential manner, the authors state that similar studies would "benefit substantially" from simultaneous PET/MRI imaging. As described in the published work, shorter imaging times mean less anesthetic stress and would result in reduced mortality, and the co-registration of the PET and MRI images would be "further improved" and would allow for better PET data through the use of such techniques as partial-volume and motion correction utilizing the MRI data. Each modality provides complementary information about heart disease and treatment to give a fuller picture of the response of the heart in response to injury and to therapy.
General Research Highlights
Our research program is investigating three developments of simultaneous PET/MRI with pre-clinical tumor models.
Marty Pagel, Ph.D., Professor, Department of Cancer Systems Imaging, UT MD Anderson Cancer Center.
(1) Improving tumor diagnoses based on imaging metabolism with PET/MRI: Our goal is to improve cancer diagnoses using tumor acidosis as a noninvasive, longitudinal biomarker for cancer imaging. Glycolytic metabolism is upregulated in many solid tumors, known as the Warburg effect, which increases lactic acid production and causes acidosis of the tumor microenvironment. Other pathologies…
Combining [F18]FAZA PET and DCE MRI to evaluate anti-cancer drug treatments
Seth Gammon, Ph.D., Assistant Professor, Department of Cancer Systems Imaging, UT MD Anderson Cancer Center.
Historically we have sequentially utilized PET/CT and then MRI in both our existing projects and emerging projects. First we are utilizing PET/CT then MRI to validate new PET reporters of inflammation. While these experiments are possible and one can reasonably compare volume of interest based analysis, precise co-registration is difficult and does not leverage the…
Tracking CAR T cell therapies with PET/MRI
Amer Najjar, Ph.D., Assistant Professor, Department of Pediatrics, UT MD Anderson Cancer Center.
The combined Cubresa PET/MRI system has been a crucial tool in advancing our understanding of adoptive cell therapy of brain tumors. These studies exploit the sensitivity of PET to define the spatial distribution of adoptively transferred immune cells and the specificity of MRI to delineate brain tumors and their responses to therapy. Over the last…