<<Yin- yang

Pseudoaneurysm of popliteal artery:

    This patient was a drug addict with history of injecting into the popliteal vessels. He presented with a pulsatile swelling in the Lt. popliteal region. Color Doppler study shows the typical cystic structure, in close relation to the Lt. popliteal artery, with swirling blood flow within it. This produces what is typically called the yin -yang sign on color doppler. (The picture below shows the typical yin yang symbol).

Grey scale imaging would show a cystic structure with swirling flow. Power Doppler may sometimes help in detecting the feeding vessel.

Pseudoaneurysms are formed by trauma to the artery, usually iatrogenic, resulting in a perfused sac surrounding the vessel. It is lined either by the media or the adventitia or even by the soft tissue surrounding the injured vessel.

CT or MR imaging can help by locating the lesion and the feeding vessel (especially on 3D reconstruction).

Case and images courtesy of Dr. Vikas Arora, MD, Ferozepur, India.

References: 1) http://www.jultrasoundmed.org/cgi/content/full/25/9/1211#SEC1

                    2) http://findarticles.com/p/articles/mi_qa3794/is_200508/ai_n15846548

Color doppler and ultrasound imaging of Deep vein thrombosis:

 Absence  of flow Lt. femoral vein (transverse section)

(longitudinal section) Lt.  femoral vein

Absent flow left politeal vein

Thrombosed Lt. iliac vein

non-compressible Lt. femoral vein

This patient showed extensive thrombosis of the Lt. iliac, femoral and popliteal veins. Grey scale B-mode ultrasound images reveal echogenic thrombus within the lumen of the affected veins. These veins also show absence of compressibility on probe pressure. Color flow imaging shows absent flow in the iliac, femoral and popliteal veins of the left side. The normal veins of the right side are shown for comparison.

Case and images courtesy of Dr. Vikas Arora, Ferozepur, India.

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