Point-of-Care Ultrasound can help to identify signs of thoracic aortic dissection.

One view to help in your assessment is the Parasternal Long Axis View.

• The aortic root should be in a 1:1:1 ratio with the left atrium and the right ventricle.
• The aortic root should be less than 4 cm (4.5 cm considered aneurysmal)

To correctly measure the aortic root:

• Measure at the Sinus of Valsalva
• Measure during diastole (when the aortic valve is closed)
• Measure leading edge to leading edge

Here is an example of an aortic root aneurysm: 

References

Kennedy Hall M, Coffey EC, Herbst M, Liu R, Pare JR, Andrew Taylor R, Thomas S, Moore CL. The "5Es" of emergency physician-performed focused cardiac ultrasound: a protocol for rapid identification of effusion, ejection, equality, exit, and entrance. Acad Emerg Med. 2015 May;22(5):583-93. doi: 10.1111/acem.12652.