Rapid large-area tissue imaging at the cellular resolution is important for clinical diagnosis. We present a probe-based confocal microendoscope (pCM) with a field-of-view (FOV) diameter over 500 μm, lateral resolution of 1.95 μm, and outer diameter of 2.6 mm, compatible with the biopsy channel of conventional gastroscopes. Compared to a conventional pCM, our system’s FOV increased by a factor of 4 while maintaining the probe size and cellular resolution—comparable to the FOV of Zeiss Axio Observer’s 20 × / 0.8 numerical aperture objective lens. Ex vivo imaging of wide areas in healthy and diseased rat gastrointestinal tract tissues demonstrates the system’s practicality.

Adaptive optics (AO) is a powerful tool for optical microscopy to counteract the effects of optical aberrations and improve the imaging performance in biological tissues. The diversity of sample characteristics entails the use of different AO schemes to measure the underlying aberrations. Here, we present an indirect wavefront sensing method leveraging a virtual imaging scheme and a structural-similarity-based shift measurement algorithm to enable aberration measurement using intrinsic structures even with temporally varying signals. We achieved high-resolution two-photon imaging in a variety of biological samples, including fixed biological tissues and living animals, after aberration correction. We present AO-incorporated subtractive imaging to show that our method can be readily integrated with resolution enhancement techniques to obtain higher resolution in biological tissues. The robustness of our method to signal variation is demonstrated by both simulations and aberration measurement on neurons exhibiting spontaneous activity in a living larval zebrafish.