Artery of Percheron Infarct: An Acute Diagnostic Challenge with a Spectrum of Clinical Presentations

Abstract

The artery of Percheron (AOP) is a variant of the paramedian thalamic vasculature that supplies blood to the medial aspect of the thalamus and the rostral midbrain. The presentation of an infarct in this territory varies widely and is often characterized by nonspecific neurological deficits, with altered mental status, decreased level of consciousness, and memory impairment being among the most common. AOP infarcts are often missed on initial computed tomography (CT) scan, and additional imaging is usually not done due to low suspicion for stroke in most cases. There have been an increasing number of reports of AOP infarction, illustrating the diversity of clinical presentations and the challenge this presents to clinicians in the acute setting. Lacking the classic signs of stroke, many of these patients experience a delay in recognition and treatment, with the majority of diagnoses occurring outside the tissue plasminogen activator (tPA) window. This case highlights the unusual presentation and diagnostic difficulty of a patient with an AOP infarct, and serves as a reminder to include thalamic pathology in patients presenting with vague neurological symptoms and no obvious signs of stroke.

Keywords: artery of percheron; bilateral thalamic infarct; ischemic stroke; paramedian thalamic infarct; stroke; thalamic infarct; thalamic vasculature; thalamus.

Figure 1. CT scan of the brain viewed with iSchemaView RAPID neuroimaging software revealed no areas of infarct.

CT, computed tomography

Figure 2. Diffusion-weighted MRI of the brain demonstrating increased signal in the distribution of the AOP.

MRI, magnetic resonance imaging; AOP, artery of Percheron.

Figure 3. MRI with apparent diffusion coefficient confirming infarct in the area supplied by the AOP.

MRI, magnetic resonance imaging; AOP, artery of Percheron.

Figure 4. Paramedian thalamic artery variants (shown in red).

A – Type I, normal anatomy; B – Type IIa, both paramedian arteries originate from the left P1 segment; C – Type IIb, the AOP originates unilaterally from the P1 segment and then bifurcates, supplying the bilateral paramedian thalamus and rostral midbrain; D – Type III, an arterial arcade connects the left and right P1 segments and gives rise to the paramedian arteries. T, thalamus; PCA, posterior cerebral artery; BA, basilar artery; AOP, artery of Percheron; P1, segment one of the posterior cerebral artery.

Figure 5. Time to drain CT perfusion source imaging showing decreased perfusion in the midbrain consistent with an AOP stroke.

CT, computed tomography; AOP, artery of Percheron.