8th Baltic Congress of Radiology

Thoracic Radiology

oral abstract

Historically MRI and PET is used to image myocardical perfusion deficit. With state of the art CT it is possible to get the same information also with CT and it is a growing tendency in the hospitals where state of the art CT is available. Main indication for stress myocardial CT perfusion imaging: Exclusion of obstructive coronary disease (+/- stenting) Myocardial bridging (with hypoperfusion) Exclusion of coronary stent obstruction Exclusion of coronary bypass obstruction Unknown retrosternal pain in physical activity Patient with pacemaker, metallic prosthesis (can´t perform MRI)

How does it work: It is a CT-based exam that combines the information provided by anatomy and myocardial perfusion (based on the distribution of iodinated contrast material during its first pass through the myocardium). Myocardial perfusion defects can be identified as hypo-attenuating areas. Performed with coronary CTA or without if the coronary CTA is performed earlier and now it is needed to specify the importance of stenosis. Protocol: Rest acquisition (coronary CTA) – for coronary anatomy, stenosis and perfusion - similar to a nuclear myocardial perfusion Imaging exam (evaluation of myocardial scar). A stress phase acquisition (dynamic perfusion) – performed under pharmacological administration of stress agents, such as Rapiscan/ each 5 ml vial contains 400 micrograms regadenoson (80 micrograms/ml); (or adenosine), to induce a vasodilatation -administration only in the presence of a cardiologist. A third delayed-phase acquisition, optional, that can be performed in case where late contrast enhancement evaluation for myocardial scar is desired. The late phase turned out to be uninformative in our experience.

Image interpretation: All coronary artery imaging datasets were combined with stress CTP according to the following interpretation: Stress-induced ischemia – is a perfusion defect under pharmacological stress and not visible at rest.  Scar / myocardial infarction – is a fixed perfusion defect (irreversible defect) and visible both in the rest and stress situations

Myocardial Stress Perfusion in CT is good alternative to MRI or PET scan which would yield similar clinical outcome and treatment plan. Some pitfalls and practical tips and tricks on how this is done in Pärnu Hospital will be presented.

In this presentation authors will give an overview how to perform myocardial stress perfusion exams with CT and what can be concluded from the exam.

1248