Determination of detection sensitivity for cerebral microbleeds using susceptibility-weighted imaging

Area of Science:

• Neuroimaging
• Biomarkers
• Medical Physics

Background:

• Cerebral microbleeds (CMBs) are small hemorrhages indicative of cerebrovascular damage.
• Susceptibility-weighted imaging (SWI) and gradient echo (GE) imaging are key MRI techniques for detecting CMBs and iron deposition.
• Accurate CMB detection and quantification are vital for understanding neurodegenerative diseases.

Purpose of the Study:

• To comprehensively analyze factors influencing Cerebral Microbleed (CMB) detection using SWI and GE imaging.
• To determine optimal echo times (TE) for quantitative CMB analysis across different field strengths.
• To develop theoretical formulas for predicting signal loss and detectability in CMB imaging.

Main Methods:

• In silico experiments simulating CMB detection on GE magnitude, phase, and SWI composite images.
• Analysis of voxel counts as a function of resolution, SNR, TE, field strength, and susceptibility.
• Utilized susceptibility maps for bias quantification and optimal TE determination for CMB quantification.

Main Results:

• Observed non-linear susceptibility trends for CMB detection on GE magnitude images.
• Demonstrated linear susceptibility trends for CMB detection on GE phase and SWI composite images.
• Identified optimal TEs for CMB quantification: 3 ms at 7T, 7 ms at 3T, and 14 ms at 1.5T for a 1-voxel CMB with SNR 20:1.

Conclusions:

• SWI and GE imaging parameters significantly impact CMB detection and quantification accuracy.
• The study provides optimized TE values for accurate CMB quantification across various field strengths.
• Developed predictive formulas based on signal loss and detectability simulations enhance future research.