A simplified method for measuring cerebral blood flow with xenon-enhanced computed tomography

Area of Science:

• Medical Imaging
• Neurology
• Biomedical Engineering

Background:

• Cerebral blood flow (CBF) measurement using xenon-enhanced computed tomography (XECT) traditionally requires monitoring xenon buildup in brain tissue and expired air.
• Current methods for expired air monitoring involve thermoconductivity analyzers or mass spectrometers, adding complexity to the XECT procedure.

Purpose of the Study:

• To investigate a simplified approach to the XECT technique by eliminating the need for separate expired air monitoring devices.
• To assess the feasibility of using the CT scanner itself to measure xenon concentration in expired air.

Main Methods:

• A novel method was proposed where patient expired air is channeled through the CT scanner's field of view via a flexible tube.
• The CT scanner simultaneously monitors xenon buildup in brain tissue and expired air.
• Phantom measurements and computer simulations were employed to validate the methodology.

Main Results:

• Phantom studies confirmed the CT scanner's capability to detect variations in xenon concentration within expired air.
• Computer simulations indicated that the proposed methodology introduces errors comparable to or smaller than existing inherent sources in XECT.
• The need for external thermoconductivity analyzers or mass spectrometers can be eliminated.

Conclusions:

• A simplified XECT technique is feasible by integrating expired air xenon monitoring directly into the CT scanning process.
• This streamlined approach has the potential to reduce complexity and cost associated with cerebral blood flow measurements using XECT.
• The proposed method demonstrates small inherent errors, making it a viable alternative for clinical application.