Platelet interaction within giant intracranial aneurysms

Area of Science:

• Neurology
• Vascular Biology
• Medical Imaging

Background:

• Turbulence in intracranial aneurysms can damage the vessel wall.
• This damage exposes platelets to the subendothelial matrix, initiating interaction.

Purpose of the Study:

• To evaluate platelet interaction within giant intracranial aneurysms.
• To determine if platelet deposition correlates with neurological symptoms.

Main Methods:

• A dual-isotope technique using Indium-111 labeled platelets and Technetium-99m labeled red blood cells.
• Calculation of the indium deposited to indium blood pool ratio (In(D)/In(BP)) to quantify platelet deposition.

Main Results:

• Platelet deposition was detected in 6 out of 13 patients, with a significantly elevated In(D)/In(BP) ratio (0.96 +/- 0.65).
• Three patients with platelet deposition experienced transient neurological deficits, and one suffered a stroke.
• Scanning electron microscopy confirmed intraluminal platelet aggregation in a surgically obtained aneurysm.

Conclusions:

• Platelet aggregation is more frequent in giant intracranial aneurysms than previously recognized.
• Data support the hypothesis that emboli from aneurysmal platelet aggregation can cause distal cerebral vessel events.