PCA Infarct-MRI
Clinical Data: Young adult presents with history of headache and seizures. MR shows acute non-hemorrhagic stroke of right PCA possibly involving P-2 segment.
Teaching points by Dr MGK Murthy
· PCA arises from top of basilar and supplies midbrain, subthalamic nucleus, basal nucleus, thalamus, mesial inferior temporal cortices
· Additionally via PCOM, supplies collateral circulation to MCA territory
· Divided by PCOM in to P1 (including thalamogeniculate ,splenial and medial as well as lateral posterior choroidal arteries) and P2 segments (posterior temporal and internal occipital)(P2A=crural cistern segment, bridges with posterior P2P Ambient cistern component)
· P3 segment of PCA refers to quadrigeminal segment and P4 is cortical segment
· Prominent Laterality of P4 segment is a reliable sign of collateral circulation positivity, from leptomeningeal anastomosis (200to 600 microns in size) M1 segment block of MCA , (starts in hours and peaks in days or weeks )on MRA
· Variant include fetal PCA (absent or hypoplastic P1) (30%)and central artery of Percheron (Bilateral ,medial thalamic and rostral midbrain perforators arise from single ,unilateral , common, P1segment)
· Etiology of stroke are like elsewhere , with cardiogenic embolization and dissection of proximal vessels as well as migraine(70% occur only in patients with aura) preferentially involving PCA
PCA Infarct-MRI
Reviewed by Sumer Sethi
on
Monday, October 17, 2011
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