Table 1.

Classification of coronary artery dilatation

Based on the shape or gross structure
Saccular	Transverse diameter is greater than the longitudinal dimension
Fusiform	Longitudinal dimension is greater than the transverse diameter
Based on the vessel wall composition
True aneurysm	Vessel wall composed of three layers: adventitia, media, and intima
Pseudoaneurysm	Vessel wall composed of one or two layers
Based on the size
Giant aneurysm (adults)	>20-150 mm in diameter
Giant aneurysm (children)	>8 mm in diameter
Based on the extent of involvement[16]
Type I	Diffuse dilatation of two or three vessels
Type II	Diffuse dilatation in one vessel and localized disease in another
Type III	Diffuse dilatation of one vessel only
Type IV	Localized or segmental dilatation

Reproduced with permission from Díaz-Zamudio et al. 2009