| Type 1 | Long (>1 cm), thin, bright, mobile in the lumen and undulating, vibrating or waving with a sail-like motion in M-mode recording (long oscillating flap) |
| Type 2 | A long but minimally mobile linear echo which was duplicated and parallel to one or two aortic walls. |
| Type 3 | A short, double linear image with a rapid systolic motion and high frequency oscillations |