  We present a benchmark pilot study in which high-resolution Full-Field
Optical Coherence Tomography (FF-OCT) is used to image human breast tissue and
is evaluated to assess its ability to aid the pathologist's management of
intra-operative diagnoses. Our aim included evaluating the safety of FF-OCT on
human tissue and determining the concordance between the images obtained with
routinely prepared histopathological material. The compact device used for this
study provides a 2 {\mu}m-lateral and a 1 {\mu}m-axial resolution, and is able
to scan a 1.5cm^2 specimen in about 7 minutes. 75 breast specimens obtained
from 22 patients have been imaged. Because the contrast in the images is
generated by endogenous tissue components, no biological, contrast agents or
specimen preparation is required. We characterized the major architectural
features and tissue structures of benign breast tissue, including adipocytes,
fibrous stroma, lobules and ducts. We subsequently characterized features
resulting from their pathological modification and developed a decision tree
for diagnosis. Two breast pathologists applied these criteria, resulting in a
demonstrable ability to distinguish between normal or benign tissue, in situ
and invasive carcinomas using FF-OCT images, with a sensitivity of 97% and 90%,
respectively, and specificity of 74% and 77% respectfully. FF-OCT shows great
potential for the evaluation of human tissue and its characterization as
normal/benign vs. lesional, for numerous ex-vivo clinical use-cases. Its high
imaging accuracy for in-situ and invasive carcinoma paves the way for
applications where a fast architectural assessment could improve the core
needle biopsy workflow, tumor margin assessments, and provides quality
assurance for tissue acquired for clinical care and research.
