DWI MRI. Right PCA stroke. The calcarine sulcus is infarcted and the patient suffers from left homonymous hemianopia. We see how the parieto-occipital sulcus differentiates MCA from PCA supply. Abnormality highlighted.
Posterior Cerebral Artery (PCA) Stroke
Anatomy
The posterior cerebral artery (PCA) covers the back 1/3 of the brain, involving the occipital lobes, the inferior temporal lobes, and some key specific areas, including the thalami and hippocampi.
Clinical Manifestations
Typically, PCA stroke affects the calcarine sulcus and the patient suffers from homonymous hemianopia.
Clinical Findings in PCA Stroke
- Visual Field Defects:
- Homonymous Hemianopia: Loss of the same field of vision in both eyes, most commonly affecting the contralateral field.
- Cortical Blindness: When bilateral PCA territories are involved, leading to total or near-total vision loss with intact pupillary reflexes.
- Memory Impairment:
- If the infarct affects the hippocampal formation, particularly in the dominant hemisphere or bilaterally.
- Visual Agnosia:
- Difficulty recognizing objects, faces, or colors, especially if the stroke impacts the inferomedial temporal lobes.
- Thalamic Pain Syndrome (Dejerine-Roussy Syndrome):
- A condition caused by ischemic damage to the thalamus that can result in severe, persistent pain and sensory disturbances on the contralateral side of the body.
- Alexia without Agraphia:
- The inability to read despite the ability to write, associated with a left occipital infarct involving the visual cortex and splenium of the corpus callosum.
- Prosopagnosia:
- An inability to recognize familiar faces, associated with bilateral occipito-temporal damage.
- Peduncular Hallucinosis:
- Visual hallucinations that are vivid, colorful, and often elaborate, which can occur with lesions affecting the midbrain.
- Cognitive and Behavioral Changes:
- Depending on the extent and location of the stroke, patients may experience changes in alertness, cognitive speed, and executive functions.
- Contralateral Sensory Loss or Weakness:
- May occur if the stroke extends to affect parts of the thalamus or the internal capsule.
Interesting Reference Regarding Hippocampal Injury
1. Hippocampal Lesion Patterns in Acute Posterior Cerebral Artery Stroke: Clinical and MRI Findings. http://dx.doi.org/10.1161/STROKEAHA.108.536144. Stroke. 2009;40:2042-2045. Originally published May 22, 2009