Mouse uterine and brain tissue MSI datasets used as examples in this study have been previously reported . Briefly, mouse uterine tissue was analyzed using nano-DESI MSI on a Q-Exactive HF-X Orbitrap mass spectrometer (Thermo Fisher Scientific, Waltham, MA) equipped with a custom-designed nano-DESI source . Mass spectra were acquired in the m/z range of 133-2000 in both positive and negative ion modes with a spatial resolution of 10 μm. Positive mode MSI data for mouse brain tissue was obtained from METASPACE , a community resource that provides open access to MSI data. The specific data were acquired using MALDI MSI in the m/z range of 600-1000 with a spatial resolution of 20 μm. The dimensions of the two MSI datasets are listed in Table .