Saturday 9 June 2012

MRI Pitfalls: Jugular vein with high signal

MRI Axial T2w image in Neck region, left side internal jugular vein show high signal where as right side internal jugular show normal T2 flow voids, Thrombosis ? 
No !!! this is artifactual high signal due to slow flow in the left jugular vein.
This is a common finding in MRI Cervical region spine on Axial T2w images and can be passed off as normal. 

It is important to consider the anatomy of the jugular veins here, which is not symmetric.
Internal jugular veins joins sub clavian veins before draining directly into the superior vena cava via innominate veins. SVC being on right side, right innominate is short. The left innominate vein, which is nearly twice as long as the right, must cross the midline to join SVC which is on right side of the mid line.
So due to slow flow or sometimes reversed flow in the left jugular vein which occur secondary to compression of this left innominate vein by the aorta as the vein passes under the sternum, there is artifactual high signal in the left jugular vein.

Reference: Practical MR Physics and case file of MR artifacts and pitfalls, Alexander C. Mamourian, MD

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