Modality Agnostic Model for Spatial Resolution in Mass Spectrometry Imaging: Application to MALDI MSI Data.

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Imaging Science

Background:

• Image resolution in mass spectrometry imaging (MSI) is critical for detailed molecular analysis.
• Factors influencing MSI resolution include probe characteristics, stage motion, and inherent noise.
• Existing models may not fully capture the interplay of these variables.

Purpose of the Study:

• To present a novel image formation model for MSI that incorporates probe size, stage velocity, and material consumption rate.
• To develop and validate a computational method for quantifying lateral resolution in MSI, considering blurring and noise.
• To establish signal-to-noise ratio (SNR) as a key determinant of MSI resolution.

Main Methods:

• Developed a new image formation model for MSI.
• Proposed a computational method using spectral decomposition to measure lateral resolution.
• Evaluated the method using a silver step edge standard imaged with matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI).
• Calculated modulation transfer function (MTF) and noise power spectrum (NPS) for single-ion images.

Main Results:

• The new model identifies probe size, stage velocity, and material consumption rate as key factors affecting image blur.
• Signal-to-noise ratio (SNR) was confirmed as the principal limitation for MSI resolution.
• The computational method successfully determined resolution by intersecting MTF and NPS.
• The algorithm was validated on both a standard and a MALDI MSI tissue dataset.

Conclusions:

• The developed image formation model provides a comprehensive understanding of MSI resolution limitations.
• The novel computational method offers a robust approach for quantifying lateral resolution in MSI.
• This work advances the capability for high-resolution molecular imaging in complex biological samples.