Significant Arterial Dissection

**Semantic type:** Disease or Syndrome

**Definition:** A dissection that impairs flow. This includes Type C (a persisting contrast medium extravasation) in the presence of ischemia, Type D (a spiral filling defect with delayed but complete distal flow), Type E (persistent filling defect with delayed antegrade flow) and Type F (filling defect with impaired flow and total occlusion).