What is the fine-grained topic of the following text: Alexandr Khrapichev, a professor at the University of Oxford, put together this selection of what he calls “virtually-sliced” fruit and vegetables by running them through an MRI machine and putting the slices into chronological order to create these deconstructed fruit and vegetable portraits. Only return the topic.
"Creating deconstructed fruit and vegetable portraits using MRI machine."