A new standard of visual data representation for imaging mass spectrometry.

PURPOSE: MALDI imaging MS (IMS) is principally used for cancer diagnostics. In our own experience with publishing IMS data, we have been requested to modify our protocols with respect to the areas of the tissue that are imaged in order to comply with the wider literature. In light of this, we have determined that current methodologies lack effective controls and can potentially introduce bias by only imaging specific areas of the targeted tissue EXPERIMENTAL
DESIGN: A previously imaged sample was selected and then cropped in different ways to show the potential effect of only imaging targeted areas.
RESULTS: By using a model sample, we were able to effectively show how selective imaging of samples can misinterpret tissue features and by changing the areas that are acquired, according to our new standard, an effective internal control can be introduced. CONCLUSIONS AND CLINICAL RELEVANCE: Current IMS sampling convention relies on the assumption that sample preparation has been performed correctly. This prevents users from checking whether molecules have moved beyond borders of the tissue due to delocalization and consequentially products of improper sample preparation could be interpreted as biological features that are of critical importance when encountered in a visual diagnostic.