1222 Figure 2. MALDI FTICR IMS and LC-ESI-MS/MS identify elevated HexCer species in a GD mouse brain. (A) H&E stain of 4L/PS-NA and control brain sections analyzed by MALDI FTICR IMS. (B) A common lipid PC 32:0 + H shows comparable signal intensities across the disease and control brains; all images signal intensities were cut off at 60%, with the color scale representing intensities. The color bars in MALDI FTICR IMS images show the signal intensity: red to blue indicates high to low levels. (C) HexCer species identified by MALDI FTICR IMS (color images) and quantified by LC-ESI-MS/MS (bar graphs under each image). HexCers are elevated in 4L/PS-NA mice brains compared with the control. Different fatty acyl chain lengths were identified, including HexCer d18:1/18:0, HexCer d18:1/20:0, HexCer d18:1/24:0, and HexCer d18:1/24:1. The control mouse brains for HexCer d18:1/20:0 and HexCer d18:1/24:0 were under detection limits by MALDI FTICR IMS. Fold changes of HexCers levels in 4L/PS-NA over control determined by LC-ESI-MS/MS are shown under each bar. n = 2 mice.