Time of acquisition and high spatial resolution mass spectrometry imaging

Abstract

The field of mass spectrometry imaging (MSI) is constantly evolving to analyze a diverse array of biological systems. A common goal is the need to resolve cellular and subcellular heterogeneity with high spatial resolution. As the field continues to progress towards high spatial resolution, other parameters must be considered when developing a practical method. Here, we discuss the impacts of high spatial resolution on the time of acquisition and the associated implications they have on an MSI analysis (e.g., area of the region of interest). This work presents a brief tutorial serving to evaluate high spatial resolution MSI relative to time of acquisition and data file size.

Advances in multimodal mass spectrometry for single‐cell analysis and imaging enhancement

“…Acquisition time and data size issues are most prevalent when performing MSI on very large regions of interest (ROIs) such as entire organ slices [52]. To overcome this issue, additional imaging modalities can be used to quickly identify ROIs that can be specifically targeted via MSI.…”

“…These experiments result in long acquisition times, large dataset sizes, and instrument wear. Further, as both acquisition time and data size have an inverse squared relationship with pixel size, decreasing the pixel size to regimes necessary to analyze cellular and subcellular objects presents a major barrier [52]. To overcome these limitations, targeted MSI acquisition via multimodal imaging has been recently developed.…”

Maximized Spatial Information and Minimized Acquisition Time of Top-Hat IR-MALDESI-MSI of Zebrafish Using Nested Regions of Interest (nROIs)

“…Eq 1 describes the relative acquisition time (t r ) of imaging the same area using a larger (D o ) and smaller (D i ) step size. 11 As described, going from a 150 to 50 μm spatial resolution would result in a 9× increase in acquisition time. Due to instability of experimental conditions such as volatile matrices under vacuum and electrospray instability, longer experiments could be subject to greater variability.…”

“…With the success of achieving 50 μm spot sizes using a reflective objective that has shorter working distance, theoretically, the spatial resolution of top-hat IR-MALDESI-MSI can be improved by a combination of both optics. , However, increasing the spatial resolution will increase the acquisition time of imaging a comparable area. Eq describes the relative acquisition time ( t r ) of imaging the same area using a larger ( D o ) and smaller ( D i ) step size . As described, going from a 150 to 50 μm spatial resolution would result in a 9× increase in acquisition time.…”

“…The nested regions of interest (nROI) method arose from the concept that it is not necessary to image the entirety of biological samples at high spatial resolutions, and it draws inspiration from other fields pertaining to high-resolution imagery. 11 In contrast to MSI, the bottleneck in highresolution biological and clinical imaging does not lie in acquisition but instead in the time and computational power required for image processing. Image compression is the most ubiquitous method to solve this problem but often does not suffice for specific challenges associated with biological images.…”