Anne Latrive

In vivo and in situ cellular imaging full-field optical coherence tomography with a rigid endoscopic probe

Full-field OCT has proved to be a powerful high-resolution cellular imaging tool for biological tissues. However the standard bulk full-field OCT setup does not match the size requirements for most in situ and in vivo imaging applications. We adapted its principle into a rigid needle-like probe using two coupled interferometers and incoherent illumination: an external processing interferometer is used for in-depth scanning, while a distal common-path interferometer at the tip of the probe collects light backscattered from the tissue. Our experimental setup achieves an axial and transversal resolution in tissue of 1.8 µm and 3.5 µm respectively, for a sensitivity of −80 dB. We present ex vivo images of human breast tissue, and in vivo images of different areas of human skin, which reveal cellular-level structures.

Multimodal evaluation of ultra-short laser pulses treatment for skin burn injuries

Thousands of people die every year from burn injuries. The aim of this study is to evaluate the feasibility of high intensity femtosecond lasers as an auxiliary treatment of skin burns. We used an in vivo animal model and monitored the healing process using 4 different imaging modalities: histology, Optical Coherence Tomography (OCT), Second Harmonic Generation (SHG), and Fourier Transform Infrared (FTIR) spectroscopy. 3 dorsal areas of 20 anesthetized Wistar rats were burned by water vapor exposure and subsequently treated either by classical surgical debridement, by laser ablation, or left without treatment. Skin burn tissues were non-invasively characterized by OCT images and biopsied for further histopathology analysis, SHG imaging and FTIR spectroscopy at 3, 5, 7 and 14 days after burn. The laser protocol was found as efficient as the classical treatment for promoting the healing process. The study concludes to the validation of femtosecond ultra-short pulses laser treatment for skinburns, with the advantage of minimizing operatory trauma.

Real-time diagnosis of vascular lesions with OCT

Non-invasive real-time imaging of vascular lesions is performed with OCT, with 10-20 micrometers resolutions at 1mm depth. The images reveal different skin layers and blood vessels (Doppler effect), the growth of which indicates vascular tumor

Intra-Operative Ex-Situ and In-Situ Optical Biopsy Using Light-CT

The field of digital pathology is evolving very quickly: there is an increasing implication of laboratories and imaging companies in the biomedical field of histology. For our part we propose a digital imaging tool based on optical interferometry with short coherence length light sources (OCT). This instrument provides, without preparation or contrast agents , virtual sections of biological tissues with a field of view (1cm 2) and spatial resolution (approximately 1 micron in 3-D) suitable for histology. We show the relevance of this approach by comparing our images obtained in minutes during surgery with histological sections obtained after a few days. In these studies we worked on fixed tissue, fresh tissue in vivo or ex vivo. Finally, an endoscopic probe based on the same principle has been validated ex-vivo for use inside the bodies of patients.