Novel Method of Noninvasive Detection and Assessment of Gas Emboli and DCS

摘要

Noninvasive functional imaging, monitoring and quantification of microbubbles forming in blood and tissues upon rapid changes in barometric pressure are extremely important for effective therapy and diagnostics of several diseases as well as for imaging and drug delivery projects. However, current techniques are unable of imaging and efficient detection of bubbles with diameter less than 50 micrometers. The goal of this proposal was to develop novel Phase- Sensitive Swept Source Optical Coherence Tomography (PhS- SSOCT) technique capable of real-time, sensitive, accurate, and noninvasive imaging, monitoring, and quantification of microbubbles in tissues. During these studies, a novel phase resolved system based on Swept Source Optical Coherence Tomography (SSOCT) has been developed. The system has an axial resolution of 10 micrometers phase sensitivity of 0.03 radians, imaging depth of up to 6 mm in air, and in-depth scanning speed of 20 kHz for a single A- line. The performance of the sensing system was carefully evaluated in optical phantoms containing gas microbubbles with different diameter. Obtained results demonstrate that bubbles with diameter greater than 10 micrometers could be detected by both structural imaging and phase response whereas bubbles with diameters less than 10 micrometers could be detected by the phase response of the SSOCT with high sensitivity. The accuracy for measurement of the diameter of gas microbubbles is limited to 10 micrometers in structural imaging and 0.01 micrometers in phase-sensitive monitoring. Preliminary studies were also performed in animals in vivo for the rapid assessment of the circulating microbubbles.