دانلود رایگان مقاله انگلیسی تصویر سازی جریان خون و وضعیت اکسیژن با اشعه فراصوتی آپتو آکوستیک - الزویر 2018

ABSTRACT

Changes in hemodynamic parameters are directly linked to biological function and physiological activity. Characterization of hemodynamics is commonly performed by Doppler ultrasound, which provides accurate measurements of blood flow velocity. Multi-spectral optoacoustic tomography is rapidly undergoing clinical translation fostered by its unique and complementary capacity for label-free mapping of the blood volume and the distribution of oxy- and deoxy-hemoglobin in blood. Here we report on a hybrid optoacoustic and ultrasound imaging approach that enables multi-modal imaging of blood flow and oxygen state using a multi-segment detector array. We further demonstrate rendering of multi-modal pulse-echo ultrasound, multi-spectral optoacoustic tomography, and color Doppler images from carotid artery of a healthy subject.

4. Discussion

Availability of new non-invasive and cost-effective imaging methods is crucial for facilitating accurate diagnosis and prevention of cardiovascular diseases. The showcased capability of mapping blood flow and oxygen state by means of the multisegment detector array may provide a complementary diagnostic value to the existing functional imaging capacities of the standalone optoacoustic and ultrasound technologies. In our experiments, it was possible to clearly distinguish between the oxygenation status of structures located at depths of at least 1– 2 cm, such as the carotid artery, the sternocleidomastoid muscles, the thyroid lobe and the jugular vein. The relevant imaging depth may yet vary among different individuals. The good imaging performance in the color Doppler measurements was made possible by the multi-segment probe design featuring a linear array segment compatible with standard implementations of Doppler technology used in the clinics [37,38].

Multi-modal functional imaging of the carotid artery bifurcation is of importance in the characterization of plaque development and stenosis, which are responsible for up to 25% of the ischemic strokes [36]. In combination with the rendered Dopplerbased blood velocity measurements, the MSOT-based metrics may contribute to a more reliable assessment of the severity of carotid artery disease. Hemodynamic measurements are commonly done in patients undergoing surgery or in critical condition. In such cases, monitoring of multiple hemodynamic parameters may help in guiding treatments in a time frame that permits intervention to prevent organ failure [39]. The capacity for simultaneous mapping of multiple hemodynamic parameters is of utmost importance in the field of neuroimaging [40] where the complex mechanisms of neurovascular coupling cannot be fully characterized using functional magnetic resonance imaging (fMRI) [41,42] or Doppler US [43]. In addition to pure hemodynamic measurements, functional optoacoustic neuro-tomography has been recently shown capable of direct mapping of neuronal activity using calcium indicators [44].