Transvaginal fast-scanning optical-resolution photoacoustic endoscopy imaging of cervical vascular morphology (Conference Presentation)

Vasculatures enable nutrient transportation, waste disposal, and immune surveillance. Due to these diverse functions, abnormal changes in vascular morphology are commonly associated with the development of various diseases, including tumor growth and metastasis, inflammatory disorders, and pulmonary hypertension. Many models linking vascular morphogenesis to the development of a particular disease have been developed for prognosis, diagnosis, or disease management. To apply these models in clinical assessment, however, a tissue biopsy of the lesion is needed. This procedure is invasive and occasionally clinically infeasible. Photoacoustic endoscopy offers in vivo label-free examination of visceral vascular morphology, but its volumetric imaging process is vulnerable to breathing movement and peristalsis, because its typical B-scan rate is ~ 10 Hz, restricted by the speed of the scanning unit and the laser pulse repetition rate. Here, we present a transvaginal fast-scanning optical-resolution photoacoustic endoscope with a 250 Hz B-scan rate over a 3 mm scanning range. After demonstrating its imaging capability and safety, we not only illustrate the morphological differences in the vasculatures of the human ectocervix, uterine body, and sublingual mucosa, but also show the longitudinal and cross-sectional differences in the cervical vasculatures of pregnant women. This technology is promising for screening the visceral pathological changes associated with angiogenesis.