Optical parameters of blood flow measured by optical coherence tomography to assess the microcirculatory changes in urethral tissues
Elena B. Kiseleva1, Olga S.Streltsova1,2, Alexander A. Sovetsky3, Anton S. Kuyarov1,2, Svetlana Yu. Zubova2, Vladimir Y. Zaitsev3, Peter A. Chizhov3, Grigory V. Gelikonov3, Natalia A. Konova1,4, Natalia D. Gladkova1; 1Privolzhsky Research Medical University, Nizhny Novgorod, Russia; 2Nizhny Novgorod Regional Clinical Hospital named after N.A. Semashko, Nizhny Novgorod, Russia; 3Institute of Applied Physics of the RAS, Nizhny Novgorod, Russia; 4Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
Abstract
It is generally accepted that in various diseases, disruption of normal blood vessel function can lead to tissue hypoxia and maintain chronic inflammation, potentially provoking the occurrence of pain signals and contributing to the pain symptoms. However, in urethral pain syndrome (UPS), circulatory disorders in the pelvic organs and tissues surrounding the urethra have not been shown to date. In our study, using Doppler ultrasound we revealed blood stasis in the veins of the small pelvis in 19% of UPS patients and all of them had an increased vascular resistance index compared to the norm (0.70[0.69; 0.74] vs 0.83[0.78; 0.84], p=0.0015). Moreover, we observed microcirculation directly in the urethral wall, which no one had studied before. Using time-domain optical coherence tomography (TD-OCT) with endoscopic probe we visualize vessels in 2D structural images of the urethral wall in patients with UPS and compared them with the normal urethra. To identify correct blood and lymphatic vessels, a series of experiments were performed, including modeling the movement of a scattering fluid at different speeds through a small diameter tube (500 μm) simulating arteriole/small artery. It was found that OCT visualization of blood vessels depends on the speed of scatterers: speckle-contrast parameter is affected, which allows for vessel cross-section delineation. Segmentation by this criterion and other optical parameters allowed us to identify a high frequency of occurrence of dilated blood and lymphatic vessels in the tissues of the urethra with a finer speckle pattern inside the blood vessels, which confirms the presence of microcirculatory disorders within the urethral tissues in UPS. The study was funded by RSF #25-15-00530 (clinical part) and RSF #22-12-00295 (physical part).
Speaker
Elena Kiseleva
Privolzhsky Research Medical University, Nizhny Novgorod
Russia
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