Venous drainage in perimesencephalic hemorrhage

Area of Science:

• Neurology
• Radiology
• Vascular Imaging

Background:

• Perimesencephalic nonaneurysmal hemorrhage (PMH) is characterized by subarachnoid blood around the midbrain.
• Clinical and radiological findings suggest a venous origin for PMH.

Purpose of the Study:

• To compare the midbrain venous drainage patterns between patients with PMH and aneurysmal subarachnoid hemorrhage (aSAH).
• To investigate the relationship between venous drainage variants and the location of hemorrhage in PMH.

Main Methods:

• Computed tomography angiography (CTA) scans of 55 PMH patients and 42 aSAH patients were reviewed.
• Venous drainage was classified as normal continuous, normal discontinuous, or primitive variant.
• In PMH patients, the side of the primitive venous drainage was compared with the side of the bleeding.

Main Results:

• A primitive venous drainage variant was observed in 53% of PMH patients versus 19% of aSAH patients.
• In PMH patients with unilateral primitive drainage, hemorrhage was consistently located on the side of the primitive drainage (100%).
• Hemorrhage was not predominantly found on the side with normal venous drainage in PMH patients.

Conclusions:

• Patients with PMH more frequently present with primitive venous drainage directly into dural sinuses compared to controls.
• The location of perimesencephalic hemorrhage aligns with the side of the primitive venous drainage.
• These findings provide further evidence supporting a venous etiology for PMH.