Pure midbrain infarction: clinical syndromes, MRI, and etiologic patterns

Area of Science:

• Neurology
• Neuroimaging
• Vascular Neurology

Background:

• Posterior circulation infarcts are a significant cause of stroke.
• Midbrain strokes are uncommon but can lead to specific neurological deficits.
• Understanding the etiology and clinical presentation of midbrain infarcts is crucial for diagnosis and management.

Purpose of the Study:

• To investigate the clinical characteristics and etiological factors of stroke patients with infarcts limited to the midbrain.
• To correlate imaging findings with neurological deficits in midbrain stroke.

Main Methods:

• Retrospective analysis of 22 patients with MRI-confirmed midbrain infarcts.
• Systematic investigations including MR imaging, MR angiography, and echocardiography.
• Comparison of infarct locations with arterial territories and clinical presentations.

Main Results:

• Midbrain infarcts were identified in 8% of posterior circulation infarct patients.
• The middle midbrain, particularly the paramedian territory supplied by the basilar artery, was most commonly affected.
• Eye-movement disorders were the predominant clinical feature, with isolated third nerve palsies being common in middle midbrain infarcts.
• Etiologies included basilar artery stenosis and small-vessel disease, with cardioembolism being less frequent than anticipated.

Conclusions:

• Midbrain infarcts present with characteristic neurological deficits, primarily affecting eye movements.
• Basilar artery stenosis and small-vessel disease are significant causes of midbrain stroke.
• The study challenges the notion that cardioembolism is the most common cause of midbrain infarcts.