CT angiography of intracranial aneurysms: a focus on postprocessing

Area of Science:

• Neurology
• Radiology
• Medical Imaging

Background:

• Computed tomographic (CT) angiography is widely used for detecting intracranial aneurysms and planning treatments.
• Despite advancements in multisection CT and postprocessing, CT angiography has not surpassed digital subtraction angiography as the reference standard.

Purpose of the Study:

• To highlight the challenges and limitations of CT angiography in intracranial aneurysm detection.
• To discuss the importance of standardized image postprocessing for CT angiography.
• To introduce an algorithm for the safe application of CT angiography in subarachnoid hemorrhage cases.

Main Methods:

• Review of existing studies on CT angiography for intracranial aneurysms.
• Discussion of various 2D and 3D visualization techniques (multiplanar reformation, maximum intensity projection, shaded surface display, direct volume rendering).
• Identification of common pitfalls associated with CT angiography.

Main Results:

• CT angiography faces limitations including poor visibility of small arteries and difficulty distinguishing certain anatomical variations from aneurysms.
• Artifacts such as kissing vessel artifact, simulated aneurysms from venous structures, and inability to visualize thrombosis/calcification on 3D images are significant challenges.
• Beam hardening artifacts from aneurysm clips can also impede accurate diagnosis.

Conclusions:

• CT angiography requires standardized postprocessing protocols to improve its reliability for intracranial aneurysm detection.
• An algorithm has been developed to guide the safe and effective use of CT angiography in patients with subarachnoid hemorrhage, considering equipment variability.