275 A Novel Method for Detecting Coronary Artery Dissection Using Computed Tomography Coronary Angiography

Abstract

Spontaneous coronary artery dissection (SCAD) is an uncommon and underdiagnosed condition, which is increasingly recognised as an important cause of myocardial infarction. Computed tomography coronary angiography (CTCA) is an emerging non-invasive tool for assessment of SCAD, not yet recommended as first-line imaging due to its lower temporal and spatial resolution compared to catheter coronary angiography. A 34-year-old female with no medical history presented with chest pain and inferolateral ST-segment elevation on electrocardiogram (ECG). Catheter coronary angiography revealed coronary artery dissection involving the left main, left anterior descending and circumflex arteries. Computed tomography angiogram revealed multifocal carotid and vertebral artery dissection, with renal artery beading, suggesting fibromuscular dysplasia. A follow-up CTCA was performed using a prospective ECG-gated dual source high-pitch helical scanner (Siemens, High Definition Flash, Forchheim, Germany). The scan was repeated 13 seconds later without further contrast. This “double-scan” had the unique effect of showing contrast “staining” in the false lumen of the dissection, occurring as a result of residual contrast not yet washed out from the first scan. The findings of this “double-scan” technique appears analogous to the contrast staining of the false lumen observed on catheter coronary angiography. Depending on the type of scanner and mode of use, obtaining more than two scans following the contrast bolus may be possible. However, the timing of repeat scans may need to vary depending on the flow characteristics of false lumen filling and haemodynamics. Further research is required to determine how to best apply this novel utility.