Advanced optical imaging technologies have experienced increased visibility in medical research, as they allow for a label-free and nondestructive investigation of tissue in either an excised state or living organisms. In addition to a multitude of ex vivo studies proving the applicability of these optical imaging approaches, a transfer of various modalities toward in vivo diagnosis is currently in progress as well. Furthermore, combining optical imaging techniques, referred to as multimodal imaging, allows for an improved diagnostic reliability due to the complementary nature of retrieved information. In this review, we provide a summary of ongoing multifold efforts in multimodal tissue imaging and focus in particular on in vivo applications for medical diagnosis. We also discuss the advantages and potential limitations of the imaging methods and outline opportunities for future developments.
Keywords: Raman spectroscopy; coherent anti-Stokes Raman scattering; confocal laser scanning microscopy; endoscopy; fluorescence lifetime imaging; in vivo; multimodal imaging; optical coherence tomography; photoacoustic imaging; reflectance laser scanning microscopy; second-harmonic generation; spectroscopy; stimulated Raman scattering; tissue; tomography; two-photon excited fluorescence.