  Mass spectrometry imaging by Fourier transform ion cyclotron resonance yields
hundreds of unique peaks, many of which cannot be resolved by lower performance
mass spectrometers. The high mass accuracy and high mass resolving power allow
confident identification of small molecules and lipids directly from biological
tissue sections. Here, calibration strategies for Fourier transform ion
cyclotron resonance mass spectrometry imaging were investigated. Sub
parts-per-million mass accuracy is demonstrated over an entire tissue section.
Ion abundance fluctuations are corrected for by addition of total and relative
ion abundances for a root-mean-square error of 0.158 ppm on 16,764 peaks. A new
approach for visualization of Fourier transform ion cyclotron resonance mass
spectrometry imaging data at high resolution is presented. The Mosaic Data-cube
provides a flexible means to visualize the entire mass range at a mass spectral
bin width of 0.001 Dalton. The high resolution Mosaic Data-cube resolves
spectral features not visible at lower bin widths, while retaining the high
mass accuracy from the calibration methods discussed.
