Content: Multiphoton microscopy (MPM) is capable of producing optical sections of resolution that can match or surpass that of wide-field microscopy with significant advantages over slide-based approaches. Avoiding the need for wax-embedding, physical cutting, and separate staining, simplifies workflow and reduces costs and labor. Digital images may become available in a shorter time frame. And the imaging is non-destructive and non-consuming, preserving tissue for ancillary studies. Optical sectioning also avoids challenges of slide imaging such as focus problems and cutting artifacts. Perceived drawbacks of MPM include long sample processing times, long data-acquisition times, high cost, and image degradation with depth. We have sought to systematically address these limitations for the practical implementation of MPM in clinical diagnostics, a technique we call Clearing Histology with MultiPhoton microscopy (CHiMP), and present preliminary data on its application to primary diagnosis of human prostate biopsies.
Technology: Samples were prepared using previously described methods of tissue processing and clearing, employing the use of benzyl alcohol/benzyl benzoate (BABB) for refractive index matching. A custom multiphoton microscope based on a polygonal (spinning) mirror was designed and built for high speed and high resolution image capture at depth. Custom software tools were developed in python for image processing and visualization of multi-level image stacks. Whole slide imaging (WSI) of traditional slides was performed on an Aperio ScanScope.
Design: Single prostate core biopsy specimens were obtained from consented individuals. Processing goals were making images available same day of biopsy. Specimens were subsequently submitted for traditional physical slides and scanning on a WSI system. Pathologists evaluated and compared image features of pseudo-colored CHiMP microscopy and WSI for primary diagnosis.
Results: All samples were successfully processed and imaged with CHiMP on the same day of biopsy. Multiphoton sections demonstrated equal or superior overall quality with only minor differences in image features. Large file sizes affected visualization performance for CHiMP images, while focus issues were noted with some WSI samples.
Conclusions: Fast image collection in a polygon-based CHiMP microscope produces timely optical sections that are amenable to primary diagnosis and present multiple advantages over traditional physical slide sections with WSI.




































