PET-MR Imaging of Coronary Atherothrombosis

Heart attacks remain a common cause of death throughout the world. The most common initiating event is the formation of a blood clot within the coronary arteries occluding blood supply to the heart. However, we know that thrombus often occurs within the coronary arteries without causing any symptoms, and may be found in patients with stable angina. We wish to investigate whether blood clots within the coronary arteries can be detected in patients who have had a heart attack and in patients with stable angina using combined positron emission tomography and magnetic resonance (PET-MR) imaging. If possible, this may provide a safe and noninvasive means of identifying patients at higher risk of heart attacks. The study will be conducted in Edinburgh Heart Centre and a total of 40 participants will be recruited from the cardiology wards, outpatient clinics and day case unit. Participants will be asked to undergo a single PET-MRI scan in addition to invasive angiography as part of standard care (non-research procedure). During the invasive angiogram procedure, an additional imaging test may be performed called Optical Coherence Tomography to provide images from within the heart blood vessels.

All patients will undergo the same intervention of having a PET-MRI scan and optical coherence tomography.

Patients will undergo combined Positron Emission Tomography and Magnetic Resonance Imaging prior to a planned invasive angiogram (performed as standard of care). During the angiogram procedure, an additional imaging test (optical coherence tomography) will be performed.

The identification of high risk plaques on T1-weighted MRI to determine whether coronary atherothrombosis can accurately be detected using non-invasive PET-MR imaging.

The correlation between high risk plaques on PET-MR and culprit plaques on invasive angiography in patients with coronary artery disease.

The relationship between positive plaques identified on PET-MR by both T1-weighted MRI and 18F-NaF PET and culprit plaques on invasive angiography

The correlation between coronary plaque thrombosis (MRI), high-risk plaque (PET) and the presence of myocardial infarction on MRI (late enhancement).

The relationship between high risk plaque features on MRI and PET with evidence of myocardial infarction on MRI.

Inclusion Criteria: Previously diagnosed coronary artery disease undergoing elective invasive angiography OR Admitted with acute coronary syndrome diagnosed by two of the following criteria 1) Elevation of cardiac biomarkers (High sensitivity cardiac troponin I greater than 34 ng/l in men and 16ng/l in women) 2) Symptoms of myocardial ischaemia 3) ECG changes indicative of acute ischaemia Exclusion Criteria: Contraindication or inability to undergo MRI scanning Renal failure (estimated glomerular filtration rate less than 30mL/min Undergoing Primary PCI Ongoing myocardial ischaemia or dynamic ECG changes Inability to provide informed consent Known allergy to gadolinium based contrast Women who are pregnant, breastfeeding or of child-bearing potential

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