Mimics of near-occlusion on conventional angiography and CTA
| Cause | Mimic | Way to Separate/Reason for Mimic |
|---|---|---|
| Similar appearance, but not atherosclerosis | Dissection | Cervical ICA lesion without severe bulb stenosis, possibly patient history |
| High ICP | Patient history, likely no focal stenosis | |
| Postradiation disease | Patient history, possibly no focal stenosis | |
| Hypoplasia | No prominent bulb stenosis, narrow bony canal | |
| Imaging protocol | NrOc mistaken for occlusion | Delayed images reveal patent lumen |
| Interpretation | Occlusion mistaken for NrOc | Ascending pharyngeal artery mistaken for ICA |
| Stenosis mistaken for NrOc | Larger opposite ICA from anatomic variations: opposite ICA supplies fetal PCA and/or both ACAs | |
| NrOc mistaken for stenosis | Partially collapsed NrOc overlooked as a normal lumen when it is not threadlike | |
| Intracranial disease mistaken for NrOc | Exclude distal disease as cause for the collapse |
Note:—PCA indicates posterior cerebral artery; ICP, intracranial pressure; NrOc, near-occlusion; ACA, anterior cerebral artery.