FIELD: medicine.
SUBSTANCE: method refers to medicine, namely to radiation diagnostics, and can be used for determination of shear modulus for blood vessel wall on the basis of intravascular optical coherence tomography. Obtaining structural images of optical coherence tomography (OCT) for the analysed section of the wall of the blood vessel. Three-dimensional segment analysis of OCT structural images is performed. Examined on segmented layers of structural image of OCT examined wall of blood vessel and structures included in its composition. Shear wave propagation is tracked in segmented layers corresponding to structures of blood vessel wall. Shear modulus is determined for the blood vessel wall. Only deforming effect on the analysed wall of the blood vessel is a pulse wave; surface area on which the deforming effect is found is considered equal to the scanning area of the used OCT intravascular probe; shearing force with which the pulse wave acts on the analysed wall of the blood vessel is calculated based on the systolic and diastolic pressure values, which in turn are obtained by means of a blood pressure sensor built into the intravascular probe of the used optical coherent tomograph. From the set of structural images of OCT of the analysed blood vessel wall, the first structural image corresponding to the absence of shear deformation, which is characteristic for the moment of detecting diastolic pressure on the blood pressure sensor, is selected. Second structural image corresponds to the maximum value of the averaged displacement for all structures of the analysed blood vessel wall. For selecting a second structural image from a sequence of structural images of the analysed blood vessel wall, removing the first structural image, averaged displacements of the structures of the analysed blood vessel wall for each structural image of the truncated sequence are calculated as the arithmetic mean of the shifts of the centres of gravity on each of the segmented layers relative to the centres of gravity of similar segmented layers of the first structural image, thickness of the deformable blood vessel wall is calculated as the arithmetic mean between the sum of the thicknesses of all segmented layers on the first structural image and the similar sum of thicknesses on the second structural image. Shift modulus value for the analysed blood vessel wall is calculated as the quotient of the product of shearing force and the thickness of the deformable blood vessel wall by the product of the area of the deforming effect and the maximum value of the averaged displacement for all structures of the analysed blood vessel wall.
EFFECT: method provides higher accuracy of determination of shear modulus for blood vessel wall due to use of pulse wave as deforming effect.
1 cl, 1 dwg
