laser mouse heart ultrasound-photoacoustic imaging systems

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Working groups of cardiological, cardio-surgical and oncological specialization at themedical faculty of the Martin-Luther-University Halle-Wittenberg are working onprojects that require modern, highly sensitive ultrasound imaging with functionallyin-depth analysis methods. The small animal high-frequency echocardiographicultrasound device-combination with a photoacoustic laser module must inherently co-registrate both signals from mouse hearts at their physiologically high beating rate (400-600 beats per minute) and other deep organs in high resolution. For the purpose of anatomical and functional analyses of hearts/neoplasiae and small vessels in the mouse model (weight between 15 and 45g), a high temporal and spatial resolution is necessary, as well as real-time imaging (e.g. for the evaluation of cardiovascular active therapeutics). An ECG-triggered digital reconstruction and reconnection of images from different cardiac cycles is expected to result in image densities of up to 10,000 frames per second. Standard echographic imaging methods, as well as functional analysis methods such as cardiac functional parameters, color Doppler, Pulse-wave Doppler, Power Doppler, Tissue Doppler, and tissue vector analyses must be feasible. Structural volumetry must be available to determine organs, infarct sizes and circumferential enlargements, as well as the three-dimensional measurement of these objects over time. Here, the signals must be normalized via the respiratory and ECG signal so that motion artifacts can be avoided. By means of contrast markers, tissue perfusions can be visualized.By combining the classical ultrasound device with a photoacoustic system, molecular analyses will be performed, such as tissue oxygenation and perfusion (via detection of oxy- and deoxyhemoglobin) and spectroscopic measurements of photoactive substances or molecular markers. Thus, (re)vascularizing and oncogenic processes can be quantified. Other wavelength ranges are used to detect contrast agents, and the spectral separation of these photoacoustic signals should make the use of several markers possible, exclusively non-radioactive. The mice will be monitored at an isoflurane anesthesia system to monitor the physiological functions such as ECG for later evaluation of intervention experiments, separately analyzable. To avoid movement artifacts by the investigator, the device should operable by voice control.