Transfer function analysis assesses resting cerebral perfusion metrics using hypoxia-induced deoxyhemoglobin as a...

Area of Science:

• Neuroimaging
• Medical Physics
• Physiology

Background:

• Hemodynamic measures typically require arterial input function (AIF) deconvolution for voxel-wise perfusion metrics.
• Transfer function analysis (TFA) presents an alternative analytic approach that bypasses the need for AIF identification.

Purpose of the Study:

• To investigate the correspondence between TFA metrics (Gain, Lag, Gain/Lag) and conventional AIF-derived resting perfusion metrics (rCBV, MTT, rCBF).
• To evaluate TFA's efficacy in discriminating regional brain perfusion compared to AIF analysis.

Main Methods:

• Utilized non-invasive transient hypoxia-induced deoxyhemoglobin as an MRI contrast agent.
• Applied both TFA and conventional AIF analyses to calculate whole-brain and regional perfusion metrics in 24 healthy participants and 1 patient.
• Compared gray matter/white matter (GM/WM) ratios for TFA and AIF metrics to assess regional discrimination.

Main Results:

• TFA metrics demonstrated congruence with conventional AIF analysis for resting perfusion measures.
• Regional GM/WM ratios were higher for TFA metrics (MTT/Lag, rCBF/Gain/Lag, rCBV/Gain) compared to AIF analysis, indicating enhanced regional discrimination.
• BOLD analysis using transient hypoxia-induced deoxyhemoglobin variations, when analyzed by TFA, yielded results comparable to conventional AIF analysis.

Conclusions:

• TFA provides a viable alternative for calculating brain perfusion metrics, eliminating the need for AIF identification.
• TFA exhibits superior regional discrimination capabilities for brain perfusion compared to conventional AIF-based methods.
• The study supports the use of TFA for analyzing BOLD signals derived from transient hypoxia for robust resting perfusion assessment.