Related Experiment Video
Updated: Aug 16, 2025
MRI and PET in Mouse Models of Myocardial Infarction
Published on: December 19, 2013
Quantification of Resting Myocardial Blood Flow Using Rubidum82 Positron Emission Tomography in Regions with
Merrill Stewart1, Sangeeta Shah1,2, Richard Milani1,2
1Ochsner Heart and Vascular Institute, Department of Cardiology, New Orleans, USA.
Abstract:
Background: Resting myocardial blood flow (rMBF) within regions of myocardial scar as measured by positron emission tomography (PET) has not yet been assessed with the radiotracer Rubidium82 (Rb82) or correlated with scar thickness. Cardiac magnetic resonance imaging (cMRI) offers high spatial resolution and identifies myocardial scar with late gadolinium enhancement (LGE). Using Rb82 PET, we sought to characterize rMBF in regions of myocardial scar of varying thicknesses determined by cMRI. Methods/Results: Patients with a history of myocardial infarction, a resting Rb82 PET study and a cMRI were identified. On cMRI, regions of infarction, defined as >50% LGE with akinesis, were sub-categorized as 50-75% LGE or >75% LGE, corresponding with increasing transmural scar thickness. PET zones of infarct based on size and %LGE by cMRI were quantified for mean and minimum rMBF. Mean rMBF (cc/min/g) in infarct zones with >75% LGE was 0.32±0.07 with a minimum rMBF of 0.19±0.03. In infarct zones with 50-75% LGE, rMBF was 0.45±0.14 (50-75% vs. >75%, p=0.002). Conclusions: We identified rMBF within cMRI confirmed regions of myocardial scar of varying thicknesses. rMBF has an inverse relationship with the extent of LGE on cMRI, with the most severe regions (>75% LGE) having mean and minimal rMBF (cc/min/g) of 0.32±0.07 and 0.19±0.03, respectively.
Insights
Resting myocardial blood flow (rMBF) measured by Rubidium-82 PET is reduced in scar tissue identified by cardiac MRI. More severe scar (higher late gadolinium enhancement) shows lower rMBF, indicating impaired blood flow in damaged heart regions.
Area of Science:
- Cardiology
- Nuclear Medicine
- Radiology
Background:
- Resting myocardial blood flow (rMBF) in myocardial scar regions using Rubidium-82 (Rb-82) positron emission tomography (PET) has not been previously assessed.
- Cardiac magnetic resonance imaging (cMRI) accurately identifies myocardial scar using late gadolinium enhancement (LGE) and provides high spatial resolution.
Purpose of the Study:
- To characterize rMBF in myocardial scar regions of varying thicknesses using Rb-82 PET.
- To correlate rMBF with scar thickness determined by cMRI.
Main Methods:
- Patients with myocardial infarction history, Rb-82 PET, and cMRI were included.
- Myocardial scar regions were defined by cMRI as >50% LGE with akinesis and sub-categorized into 50-75% LGE or >75% LGE.
- Mean and minimum rMBF were quantified in PET-defined infarct zones corresponding to cMRI scar severity.
Main Results:
- Mean rMBF in infarct zones with >75% LGE was 0.32±0.07 cc/min/g, with a minimum rMBF of 0.19±0.03 cc/min/g.
- Infarct zones with 50-75% LGE showed higher mean rMBF (0.45±0.14 cc/min/g) compared to >75% LGE zones (p=0.002).
Conclusions:
- Rb-82 PET can quantify rMBF within myocardial scar regions identified by cMRI.
- A significant inverse relationship exists between rMBF and the extent of LGE on cMRI, with more severe scar exhibiting lower blood flow.
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