A protocol for rapid, label-free histochemical imaging of fibrotic liver

Mid-infrared microscopy is a non-destructive, quantitative and label-free spectroscopic imaging technique that, as a result of recent instrument advancements, is now at the point of enabling high-throughput automated biochemical screening of whole histology samples. Currently the mid-infrared field is undergoing a paradigm shift that has not been seen since the introduction of scanning Fourier Transform interferometric spectrometers. The latest mid-infrared microscopes are powered by tunable quantum cascade laser (QCL) sources which offer a number of advantages including measurement protocol flexibility, ease-of-use and a greatly enhanced data acquisition speed at high spectral and spatial resolution. In this study we use a wide-field QCL infrared microscope to develop and validate a fast four-frequency protocol for imaging fibrosis in unstained liver tissue. We compare our results to the gold standard Masson's trichrome histochemical staining protocol.