METHOD OF DETERMINING AND DIFFERENTIATION MICROEMBOLUSES IN BRAIN BLOOD STRAM BY MEANS OF ULTRASONIC DOPPLER SYSTEM Russian patent published in 2016 - IPC A61B8/06 

FIELD: medicine.

SUBSTANCE: invention refers to medicine, namely to functional diagnostics, and can be used in neurology, cardiovascular surgery, neurosurgery. Ultrasonic Doppler system transmitter emits ultrasonic high-frequency signals, having pre-set frequency. Reflected Doppler signals are registered by receiving unit. One performs preliminary analogue processing of received signals with different power and containing background blood flow signals and high intensity transient signals. Reflected Doppler signals are converted in ultrasonic Doppler system analogue-to-digital converter. Background blood flow signals are recorded and background power of Doppler signals and current power of Doppler signals blood flow are calculated. High intensity transient signals are recorded in case of current power exceeding over background power by value of given power detection threshold. For detection of microembolus signal reflected Doppler signals are recieved from two main probing depths, main depth at which analysed vessel is located, and auxiliary depth. For each depth high intensity transient signals are recorded. Current high-intensity transitory signal is marked as a microembolus signal if said signal is fixed only on main depth, and it is absent on auxiliary one and its duration is within preset limits. In all other cases it is marked as an artifact signal. Calculating microembolus signal duration, minimum and maximum frequencies and frequency modulation index by formula: FMI=(Fmax-Fmin)/Thits,

where FMI is dimensional frequency modulation index, Hz/s;

Fmax is maximum microembolus signal frequency, Hz;

Fmin is minimum microembolus signal frequency, Hz;

Thits is microembolus signal duration, s.

Microembolus is classified as material, if frequency modulation index is less than preset minimum differentiation threshold, as gas, if frequency modulation index is greater than preset maximum differentiation threshold and indeterminate, if frequency modulation index is between preset maximum and minimum differentiation thresholds.

EFFECT: method provides high sensitivity in detecting microemboluses and high specificity of determining their composition due to obtaining reflected beams data with different depths of one frequency beam.

1 cl, 3 ex