Medical imaging
Because CT and MRI are sensitive to different tissue properties, the appearances of the images obtained with the two techniques differ markedly. In CT, X-rays must be blocked by some form of dense tissue to create an image, so the image quality when looking at soft tissues will be poor. In MRI, while any nucleus with a net nuclear spin can be used, the proton of the hydrogen atom remains the most widely used, especially in the clinical setting, because it is so ubiquitous and returns a large signal. This nucleus, present in water molecules, allows the excellent soft-tissue contrast achievable with MRI.
Cognitive genomics
Functional magnetic resonance imaging (fMRI) is a widely available imaging technique that measures changes in blood flow in imaged tissue. It’s commonly used in neurophysiological studies to determine neuron activation. Unlike a standard MRI, fMRI can be used to actively measure subject neuronal activity as the patient performs tasks. This technique isn’t used on conscious non-human primates due to the inability to restrain the primates during imaging. However, fMRI illustrates regional brain activity when performed on primates that performed tasks over an extended period of time and were then anesthetized.