Acute P1 occlusion with PCA ischemia penumbra (CT perfusion)

Case contributed by Craig Hacking


Acute onset dysphasia and dense right-sided weakness with confusion. Onset 120 minutes before scan. Hypertension. AF. Previous mitral valve repair, severe aortic regurgitation and biventricular cardiac failure. Previous stroke. Independent at home.

Patient Data

Age: 70 years
Gender: Male

No intracranial hemorrhage. Stable hypodensity in the left temporal lobe in keeping with a previous infarct. Small hypodensity in the inferior right frontal cortex also in keeping with an established infarct. Periventricular hypoattenuation in keeping with chronic small vessel ischemic disease. Grey-white matter differentiation has been maintained elsewhere in the brain. The proximal left posterior cerebral artery appears hyperdense.

9mm filling defect in the proximal left posterior cerebral artery (P1).

Irregularity of the left MCA (M1 and M2 segments) and to a lesser degree the left A2 likely secondary to intracranial atherosclerotic disease.The vertebral, basilar and carotid arteries enhance normally. Symmetric collateral vessels. Normal three-vessel takeoff from the aortic arch.

No features of dural sinus thrombosis.

Increased time parameters in the left occipital lobe in keeping with a large penumbra of the entire left PCA territory. Decreased CBV and CBF in the central aspect of the left occipital lobe in keeping with core infarct. Core approximately 33%.


Proximal left PCA occlusion with perfusion maps showing ischemic penumbra of the left occipital lobe and approximately 33% of central core infarct.

Stable chronic infarct in left temporal lobe. Small chronic cortical infarct in the right frontal lobe, which was not seen on the previous CT head.

Neurointerventional radiologist notified.

Mechanical thrombectomy (ECR)


Left P1 occlusion extending to but not involving the basilar terminus. Retrieved approximately 2 cm of black thrombus in a sinlge pass. Post ECR recanalization of left P1 but the left P3 occlusion persists (not pursued). TICI 3.

Increased DWI signal intensity in the left occipital lobe, the medial aspect of the left thalamus, posterior left thalamus, superior left vermis, left cerebellar hemisphere, left midbrain in keeping with evolving cerebral, cerebellar, thalamus and midbrain infarcts.

Focal area of gyriform restricted diffusion in the right frontal lobe that may represent a focal cortical laminar necrosis.

Marked T2 signal hyperintense change in the left temporal lobe and right frontal lobe that may be secondary to previous ischemic insult/injury. Mild to moderate periventricular white matter T2 signal hyperintensity suggests chronic small vessel ischemia. 

Case Discussion

Good example of acute ischemic stroke with left P1 occlusion and penumbra with minimal core infarct. The patient was successfully treated with mechanical thrombectomy.

Post ECR MRI shows involving infarcts in the left posterior circulation and suspected focal area of cortical laminar necrosis in the right MCA territory.

How to use cases

You can use Radiopaedia cases in a variety of ways to help you learn and teach.

Creating your own cases is easy.