Red chlorophyll: the new barium?

Imaging of gastrointestinal (GI) motility remotely through the abdominal wall has always been a tradeoff between resolution and invasiveness. Skin reflects and/or absorbs wavelengths of radiation in the ultraviolet and visible ranges, but is largely transparent to both high-energy radiation (Gamma to X-rays; <0.1-10 nm) and low-energy radiation (infrared to radio waves; 700 nm-10 m). Imaging using short wavelength radiation such as X-ray cinematography has excellent spatial and temporal resolution, but ionization can produce acute and long-term deleterious effects to the patient or animal. Other 'slice-based' imaging techniques such as ultrasound/MRI/CT minimize tissue damage, but are limited in the planar area that can be imaged in a timely fashion. This viewpoint article will summarize and explore the implications of recent advances in infrared imaging of the GI tract, in particular, an article published in this issue of NGM entitled 'In vivo dynamic imaging of intestinal motions using diet-related autofluorescence' in which the authors have used infrared imaging in combination with that most elusive ingredient, standard mouse chow, to capture the motions of the mouse GI tract.