Self-Calibrated Stimulated Raman Scattering Spectroscopy for Rapid Cholangiocarcinoma Diagnosis

Cholangiocarcinoma (CCA) is an aggressive malignancy with poor clinical outcomes. The current "gold standard" diagnostic approach, endoscopic retrograde cholangiopancreatography (ERCP)-obtained biopsy, has a relatively low sensitivity (i.e., ∼50%). Here, we developed a bile-based diagnostic system using transient stimulated Raman scattering (T-SRS). Except for the tolerance to autofluorescence inherited from traditional SRS spectroscopy, T-SRS features quantum-limit spectral line shapes and is further improved with self-calibration ability in this research. These advantages make the acquired Raman spectra insensitive to the drifting of the excitation parameters, facilitating long-term reliability. Based on the T-SRS spectra in the C-H stretching region from 76 bile samples accumulated over more than 1 year, we demonstrated high accuracy (i.e., 85 ± 3%) and sensitivity (i.e., 87 ± 9%) for classification between CCA and benign diseases. The T-SRS acquisition only requires ∼9-μL bile samples and features a drastically improved time cost. This study suggests that the self-calibrated T-SRS analysis of the bile sample offers a promising approach for rapid CCA diagnosis.