"Pseudodissection occurs when aortic motion causes the spurious appearance of an intimal flap in a normal ascending aorta on non-cardiac gated images 1-3. This artifact is more likely when heart rate is high. In patients with pseudodissection, other adjacent vascular structures like the SVC, pulmonary artery, and left and right atria often have similar flap-like motion artifacts. If uncertainty persists regarding whether an apparent intimal flap is real or spurious, an ECG gated scan can be used to confirm or rule out dissection."