Estimation of arterial nonlinear compliance using ultrasound images/Arterijos netiesinio standumo ivertinimas naudojant ultragarsinius vaizdus

In order to better detect the early stage of disease nonlinear compliance of artery is considered. Algorithm and MATLAB program analysis M and D mode ultrasound images is created. Program applied for the calculation internal radius of artery and blood flow during the cardiac cycle. Nonlinear Windkessel artery model and by sphygmomanometer calibrated typical blood pressure waveform used for calculation parameters a and b, characterizing exponential dependence compliance with pressure. Experiment "in vivo" with local carotid artery show, that a vary in the range (2,52 ... 3,29) ml/mmHg, b--(0,014 ... 0,021) [mmHg.sup.-1], volume compliance--(0,2 ... 1,2) ml/mmHg. These values match with data, presented in the literature. Direct real time ultrasound measurements of local arterial radius, intima-media thickness and blood velocity allow to increase the plausibility of estimation. Ill. 7, bibl. 6, tabl. 1 (in English; abstracts in English and Lithuanian). Siekiant sudaryti ankstyvujy pokyciu diagnozavimo metodika, nagrinejamas netiesinis arterijos standumas. Sukurti ultragarsiniu M ir D rezimo vaizdu apdorojimo algoritmai ir MATLAB programos arteriju vidiniu sieneliu storiui bei kraujo debitui sirdies pulso metu skaiciuoti. Naudojant netiesini Vindkeselio arterijos modeli ir su sfigmomanometru kalibruota tipine kraujo slegio laiko funkcija gautos parametru a ir b reiksmes, apibudinancios eksponentine standumo priklausomybe nuo slegio. Nustatyta, kad karotidines arterijos parametras a keitesi nuo 2,52 iki 3,29 ml/mmHg, b--nuo 0,014 iki 0,021 mmHg-1, turinis standumas--nuo 0,2 iki 1,2 ml/mmHg. Gauti in vivo iverciai atitinka literaturoje pateikiamus duomenis. Tiesioginiai arterijos lokalinio spindulio ir intima-media storio ir kraujo srauto matavimai igalina padidinti arterijos ivertinimo patikimuma. Il. 7, bibl. 6, lent. 1 (anglu kalba; santraukos anglu ir lietuviu k.).