Conventionally, patients who have had CAD diagnosed by angiography need to undergo additional functional examinations such as nuclear stress imaging or cardiac MR to demonstrate that a narrowing is hemodynamically important. At St Joseph’s we can offer an alternative as part of their CT Angiogram appointment. MRI cardiac perfusion, which when combined with CTCA allows the complete assessment of a patient’s CAD in a single sitting, with a high level of accuracy but low radiation dose.
After an injection of a special drug to dilate blood vessels in the heart a further MRI scan can be performed. Diseased coronary arteries will not dilate hence causing a ‘perfusion defect’ on the scan.
Several studies have shown that MRI cardiac perfusion can be performed with good, if not better agreement than other conventional, non-invasive imaging modalities and with several advantages. The radiation dose from perfusion MRI is significantly less than nuclear perfusion imaging and in combination with CT angiography data allows patients with significant CAD and no flow limiting narrowings (the artery is narrow but the blood flow is acceptable) to be identified.