Practical aspects of OCT imaging in tissue engineering.

Optical coherence tomography (OCT) is a non-destructive, non-invasive imaging modality conceptually similar to ultrasound imaging but uses near-infrared radiation rather than sound. It is attracting interest throughout the medical community as a tool for ophthalmic scanning (especially of the retina) and potentially for the diagnosis of many other illnesses such as epithelial cancer, connective tissue disorders, and atherosclerosis, as well as for surgical guidance. More recently, it has begun to be explored as a tool for the real-time monitoring of the growth and development of tissue-engineered products. OCT has certain unique advantages over traditional confocal microscopy; in particular, it can image to depths measured in hundreds of microns rather than tens of microns in intact biological tissues and with working distances in excess of 1 cm. Also it possesses label-free contrast for imaging ordered collagen (via birefringence), flow velocity and local shear-rate (via Doppler shifts), and sub-cellular structure (via coherent speckle contrast). The purpose of this short review is to introduce OCT technology and also give guidelines on its practical implementation to the interested researcher.