Sunday 18 September 2011

Differentiation between ICA and ECA on MR Angio

On either side CCA divides into ICA and ECA at the level of upper border of thyroid cartilage.
Differentiating points between ICA and ECA on MR Angiogram
Caliber : ICA relatively larger in diameter than ECA.
Branches in neck: Look for the side branches, a branch arising from the vessel it has to be ECA as ICA gives no neck branches.
Alignment : ECA is in alignment with CCA where as ICA has a sharp angulation at its origin and then ascend upward, this is to reduce chances of ascend of emboli from CCA into ICA intra cranially.
Bulbar portion: a mild smooth dilatation involving proximal most portion of ICA near its origin is normal bulbar portion.
Location : on cross sectional row images ICA is anterio medial to ECA. 

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