Evaluation of breast tissue with confocal strip-mosaicking microscopy: a test approach emulating pathology-like examination

Abstract

Abstract. Confocal microscopy is an emerging technology for rapid imaging of freshly excised tissue without the need for frozen-or fixed-section processing. Initial studies have described imaging of breast tissue using fluorescence confocal microscopy with small regions of interest, typically 750 × 750 μm 2 . We present exploration with a microscope, termed confocal strip-mosaicking microscope (CSM microscope), which images an area of 2 × 2 cm 2 of tissue with cellular-level resolution in 10 min of excision. Using the CSM microscope, we imaged 34 fresh, human, large breast tissue specimens from 18 patients, blindly analyzed by a board-certified pathologist and subsequently correlated with the corresponding standard fixed histopathology. Invasive tumors and benign tissue were clearly identified in CSM strip-mosaic images. Thirty specimens were concordant for image-to-histopathology correlation while four were discordant.

Multiscale nonlinear microscopy and widefield white light imaging enables rapid histological imaging of surgical specimen margins

“…Using a 3x image averaging, a 1 mm 2 field size, and 490 nm sampling density, acquisition of one frame followed by translation and a software delay of ~500 ms requires less than 1 second. Accounting for overlapping of adjacent frames to enable seamless stitching, this is a net equivalent pixel rate of 4 MP/s and a time per area of 2.3 minutes per cm 2 , approaching some of the fastest area imaging rates reported in the literature [48].…”

“…The large area and limited imaging time during surgery pose a substantial barrier for clinical translation, and in the case of FSA, typically limits evaluation of the excised tissue to a small subset of what would normally be evaluated with post-operative FFPE histology [46]. Previous work developing high speed strip scanning confocal microscopy has demonstrated microscopic resolution and nuclear contrast with imaging rates as fast as 1.5-3 minutes per cm 2 [47,48]. However, even at this rapid imaging rate, it would still take several hours to comprehensively image the face of a large lumpectomy cut into bread loaf specimens, which would represent an unacceptable delay of surgery.…”

Raman-Encoded Molecular Imaging with Topically Applied SERS Nanoparticles for Intraoperative Guidance of Lumpectomy

“…low sensitivities of <70% have been reported (4,5)). A number of other ex vivo imaging techniques have been proposed to assess breast margins, such as confocal microscopy (6), nonlinear microscopy (95.4% sensitivity, 93.3% specificity) (7,8), optical coherence tomography (90–100% sensitivity, 75–82% specificity) (9,10), optical coherence microelastography (11), light reflectance spectroscopy (74% sensitivity, 86% specificity) (12,13), autofluorescence lifetime measurement (12) and intrinsic Raman spectroscopy (94–100% sensitivity, 96–100% specificity) (14–16). Optical-sectioning microscopy techniques, such as confocal microscopy and nonlinear microscopy, can obtain high-resolution and high-contrast images of freshly resected tissues.…”

“…However, applying these techniques for intraoperative imaging of large tissue surfaces is challenging due to the relatively slow speed of these point-by-point imaging techniques. In addition, these techniques suffer from an extremely limited depth of focus, necessitating elaborate tissue-flattening or volumetric imaging strategies to visualize a large tissue surface with topological irregularities (6,7). Spectroscopic methods (e.g.…”

Label-free optical imaging technologies for rapid translation and use during intraoperative surgical and tumor margin assessment

“…The following sections review some of the current optical imaging technologies that are being developed to address these needs. 18 demonstrated imaging of 4-cm 2 fresh breast tissue specimens within 10 min at subcellular resolution. Accurate identification of varying types of breast malignancies was demonstrated, and the study was enhanced by clinically relevant data analysis in which entire images were reviewed (rather than a selection of smaller ROIs) and compared to standard histology.…”