In M-mode moves the flap to the false lumen in systole.
Spontaneous echo contrast and thrombus can be seen in the false lumen.
On color Doppler, flow is shown slower systolic by secondary or re-entry to tear the false lumen.
The false lumen (especially in chronic dissections) tends to be larger in comparison to the true lumen.
Evaluation of coarctation aortae
With the origin of the carotid and subclavian artery are landmarks for locating the coarctation.
Remember that collateral will reduce the systolic speed but the diastolic gradient persists. In the presence of diastolic forward flow is spoken of a hemodynamically significant coarctation. Typically CW Doppler signal of descending aorta with diastolic forward flow fitting in hemodynamically significant coarctation