Non-invasive lipid measurement in living insects using NMR microscopy

Abstract

Summary Nuclear magnetic resonance (NMR) microscopy allows to image and to quantify the distribution of NMR-active nuclei in living specimen. Using high-field NMR microscopy at 14.1 T magnetic field strength and strong gradients up to 3 T/m, we show in this study that separation of fat and water nuclear resonances in living insects can be achieved. Comparing it to destructive conventional photometric and weighing measurements, we demonstrate exemplarily in the European spruce bark beetle, that NMR can be efficiently used to quantify absolute fat and water content in living insects. Additionally, anatomic images with a spatial in-plane resolution up to 10 μm and with high soft tissue contrast were acquired. For the first time, we demonstrate, that fat distribution and fat consumption of living insects can be obtained by magnetic resonance imaging (MRI). This enables future research to address questions where single individuals have to be measured several times, which is not possible with conventional destructive methods.