Malignant carotid invasion: sonographic diagnosis.

Malignant invasion of the carotid artery is an ominous complication of squamous cell carcinoma that can be suspected from B-mode sonography. A loss of carotid wall integrity seen as a break or step off of the inner wall suggests early involvement. Frank tumor invading the lumen is an end-stage event. Both ultrasound and magnetic resonance imaging are 100% sensitive in the evaluation that no carotid involvement has occurred. In one study, ultrasound was 75% specific and magnetic resonance was 87.5% specific. If the ultrasound is problematic, magnetic resonance may clarify the issue.