Middle cerebral artery fenestration

Last revised by Craig Hacking on 5 Jun 2017

Middle cerebral artery (MCA) fenestration is a very rare anatomical variant of the middle cerebral artery, incidentally found during MR or CT angiography. It has an incidence of ~0.6% (range 0.2-1%) 1.

Fenestration is the division of the vessel into two separate parallel channels which rejoin distally. It usually does not have any clinical significance but an aneurysm may arise from the proximal fenestration end.

It may mimic a dissection.

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Cases and figures

  • Figure 1: illustration
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  • Case 1: with ICA aneurysm
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  • Case 2: right MCA fenestration
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