Doppler optical coherence tomography and co-registered autofluorescence imaging of peripheral lung cancer

Diagnosis of peripheral lung nodules is challenging because they are rarely visualized endobronchially. Imaging techniques such as endobronchial ultrasound (EBUS) are employed to improve tumor localization. The current EBUS probe provides limited nodule characterization and has an outer diameter of 1.4 mm that restricts access to small peripheral airways. We report a novel co-registered autofluoresence Doppler optical coherence tomography (AF/DOCT) system with a 0.9 mm diameter probe to characterize peripheral lung nodules prior to biopsy in vivo. Method: Patients referred for evaluation of peripheral lung nodules underwent bronchoscopy with examination of standard EBUS and the novel AF/DOCT system. The lesion of interest was first identified with EBUS and then imaged with the AF/DOCT system. The abnormal area was biopsied. AF/DOCT images of pathology proved lung malignancies were reviewed by a panel of a pathologist, respirologists, and AF/DOCT experts. Results: Eleven patients with biopsy proven lung cancer underwent examination with AF/DOCT. The majority of the cancers were adenocarcinoma. AF/DOCT images were obtained in all patients. There were no complications to the procedures. Lung abnormalities visualized in AF/OCT images were observed in 11 cases. In one case large blood vessels were identified and biopsy was avoided. Conclusion: In this pilot study, AF/DOCT obtained high quality images of peripheral pulmonary nodules. The present study supports the safety and feasibility of AF/DOCT for the evaluation of lung cancer. The addition of Doppler information may improve biopsy site selection and reduce hemorrhage.