AHA classification and AHA-MR imaging–based classification
| AHA Classification | Carotid MR Imaging–Based AHA Classification from Cai et al45 |
|---|---|
| Type I: initial lesion with foam cells | Type I–II: near-normal wall thickness, no calcification |
| Type II: fatty streak with multiple foam cell layers | |
| Type III: pre-atheroma with extracellular lipid pools | Type III: diffuse intimal thickening or small eccentric plaque with no calcification |
| Type IV: atheroma with a confluent extracellular lipid core | Type IV–V: plaque with a lipid or necrotic core surrounded by fibrous tissue with possible calcification |
| Type V: fibroatheroma | |
| Type VI: complex plaque with possible surface defect, hemorrhage, or thrombus | Type VI: complex plaque with possible surface defect, hemorrhage, or thrombus |
| Type VII: calcified plaque | Type VII: calcified plaque |
| Type VIII: fibrotic plaque without lipid core | Type VIII: fibrotic plaque without lipid core and with possible small calcifications |