Giant Intracranial Aneurysms at 7T MRI

Area of Science:

• Vascular Neurology
• Medical Imaging
• Histopathology

Background:

• Giant intracranial aneurysms are rare but serious vascular conditions.
• High morbidity and mortality rates are associated with these aneurysms.
• Histopathologic examination has been the primary method for visualizing aneurysm wall microstructure.

Purpose of the Study:

• To assess giant intracranial aneurysms and their wall microstructure using 7 Tesla (7T) Magnetic Resonance (MR) imaging.
• To evaluate the potential of in vivo 7T MR imaging to visualize structures previously only seen in histopathology.
• To correlate imaging findings with histopathologic specimens.

Main Methods:

• In vivo evaluation of seven giant intracranial aneurysms using 7T MR imaging.
• Utilized Time-of-Flight Magnetic Resonance Angiography (TOF-MRA) and Susceptibility-Weighted Imaging (SWI) sequences.
• Histopathologic examination of two aneurysms for comparison.

Main Results:

• Seven giant intracranial aneurysms were evaluated, with six showing intraluminal thrombus.
• Aneurysm walls were clearly depicted as hypointense on TOF-MRA and SWI.
• The characteristic triple-layered microstructure of aneurysm walls was visualized in all evaluated aneurysms via 7T MR imaging.
• Imaging findings suggested iron deposition in the aneurysm walls, consistent with histopathologic findings.

Conclusions:

• In vivo 7T TOF-MRA and SWI are effective in delineating giant intracranial aneurysm walls.
• This advanced MR imaging technique successfully visualizes the triple-layered wall microstructure.
• 7T MR imaging provides a non-invasive method to study aneurysm wall characteristics, complementing histopathologic analysis.