IS it possible to scan the heart of an outpatient in a few seconds and visualise the heart arteries in three-dimensional views without inserting a tube into the heart arteries? The answer is yes. Over the past decade, advances in imaging technology has resulted in an increasing use of non-invasive Computed Tomography (CT) X-ray scan to image the heart arteries. Unlike coronary angiography (CAG), CT of the heart arteries not only allows visualisation of the lumen but also allows the wall of the artery to be visualised in any plane and detailed analysis can be performed to assess whether the narrowed segment has soft "vulnerable plaques", hardened plaques or calcium deposits.

It is not uncommon for disease in the same heart artery to be interpreted differently when visualised by different imaging techniques. Extensive diffuse plaque and narrowing of a heart artery with a diffusely narrowed lumen which can clearly be seen on the CT images can appear as an apparently "normal" artery with a diffusely small lumen on CAG.

The usefulness of three-dimensional visualisation becomes more apparent in situations where the CAG shows areas of narrowing alternating with widened segments along an artery, presenting doctors with the dilemma of trying to determine whether the narrower segments represent segments which are narrowed by cholesterol deposits or whether the apparently narrower segments are normal, and the widened segments are actually diseased due to abnormal swelling of the arterial wall, also called "ectasia".