Online Journal
IF値: 1.878(2021年)→1.8(2022年)


Journal of Medical Ultrasonics

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1991 - Vol.18

Vol.18 No.06

Original Article(原著)

(0603 - 0611)

臍帯動脈血流速度波形に影響する因子に関する研究 -数理モデルをもちいたコンピュータ・シミュレーション-

Factors Influencing Umbilical Artery Velocity Waveform -Computer Simulation of Mathematical Model-

名取 道也1, 大矢 晃久2, 吉田 丈児1, 境田 通泰1, 田中 守1, 河野 八朗1, 石本 人士1, 小林 俊文1, 野沢 志朗1

Michiya NATORI1, Akihisa OHYA2, Joji YOSHIDA1, Michiyasu SAKAIDA1, Mamoru TANAKA1, Hachiro KONO1, Hitoshi ISHIMOTO1, Toshibumi KOBAYASHI1, Shiro NOZAWA1

1慶応義塾大学医学部産婦人科学教室, 2慶応義塾大学理工学部電気工学科

1Dept. of Obstetrics and Gynecology, School of Medicine, Keio University, 2Dept. of Electrical Engineering, Faculty of Science and Technology, Keio University

キーワード : Simulation, Mathematical model, Umbilical artery, Velocity waveform, Pulsatility index

Researchers have discussed the idea of increasing peripheral resistance and elevating values of the umbilical artery waveform indices. This study aimed to reveal the factors influencing these waveform indices. The electrical circuit model of umbilical artery to placenta circulation was converted into a mathematical one.
The computer simulations revealed that blood pressure elevation lowered these indices and that decreases in the umbilical arterial diameter elevated the indices. Increased placental resistance elevated the indices, but the relationship was not linear. In this non-linear relationship, a 2 SD increase in the pulsatility index (PI) , corresponding to a 30% increase in the mean value, resulted in a 50% obstruction of the placental unit. An increase in the index of greater than 100% is feasible, but placental obstruction of more than 70% is not feasible in live fetuses. This suggests that more factors, besides resistance, cause index elevation. In recent reports using animal models, resistance elevation induced by angiotensin II was shown to be irrelevant to the index. However, this simulation has suggested its relevance in terms of the blood pressure elevation.
Simultaneous simulation of pressure elevation and resistance increase showed small changes to the indices when unit obstruction is below 60%. This simulation also revealed that a single index value corresponded to multiple values for pressure and resistance. Simulation revealed that at least three factors may influence a waveform index and different circulatory conditions may indicate the same indices.