Coronary Artery Imaging

Coronary and Cardiac Anatomy

Basic anatomy

Heart

It consists of four chambers and the vessels that enter and leave.
Blood from the body enters the right atrium (RA) through the SVC and IVC. It then goes through the tricuspid valve (TV) into the right ventricle (RV). The RV pumps blood through the pulmonary artery (PA) into the lungs. From the lungs, the blood goes via the pulmonary veins (PV) into the left atrium (LA) and via the mitral valve (MV) into the left ventricle (LV). The LV pumps blood into the body through the aorta (AO), passing through the aortic valve (AV).

All the anatomy shown here are from images obtained at our institute.

Coronary

There are four major coronary arteries.

RCA

The right coronary artery (RCA) arises from the right coronary sinus of the aorta. It courses in the atrio-ventricular groove between the RA and RV and reaches the base (crux) of the heart. It mainly supplies the RV and parts of the septum and basal LV. In 85% of patients, it is the dominant artery, which means that it gives off the posterior descending artery (PDA) that supplies the inferior wall of the LV.

LM

The left main is a short vessel that arises from the left coronary sinus of the aorta and then branches into the left anterior descending (LAD) and circumflex (CX). It may be very short or long (upto 2cm) or sometimes absent. Disease in the LM can be devastating.

LAD

It arises usually from the LM, but sometimes directly from the aorta. It courses anteriorly and inferiorly in the inter-ventricular groove between the RV and the LV and supplies most of the anterior wall of the LV upto the apex and the septum. It has septal and diagonal branches, which are often large.

CX

It arises usually from the LM, but sometimes directly from the aorta. It courses in the left AV grove between the LA and LV and goes towards the base (crux) of the heart. In the majority of patients who have right dominance, the distal CX is hypo plastic, thin or absent. In 8-10% of patients, there is left dominance, where the PDA arises from the CX. In about 5-10% of patients, there is co-dominance, where the PDA arises from the RCA, but another artery, the PL, arises from the CX. The CX supplies a large part of the lateral and sometimes the inferior wall of the LV and has obtuse marginal branches.