PROBLEM TO BE SOLVED: To provide an apparatus for measuring intravascular diameter which measures the intravascular diameter d accurately.SOLUTION: An apparatus for examining the intravascular endothelial function (the apparatus for measuring the intravascular diameter) 30 has an intraluminal diameter calculation means 100. When an ultrasonic wave is emitted from an ultrasonic probe 12 and reflection signals SR from an arterial blood vessel 20 are detected, the intraluminal diameter calculation means calculates the intravascular diameter d on the basis of the interval between two groups of reflection signal waves SR1 and SR2 among the reflection signals SR which correspond to two groups of reflection wave signals SR1 and SR2 reflected from the wall of the blood vessel 20 and contained in the reflection signals SR. Because the reflection signals SR contain all strong or weak minute amplitudes, the intravascular diameter d is calculated on the basis of the interval between two groups of minute reflection waves from the inner membrane of an arterial blood vessel which are likely to be eliminated by an envelope processing for displaying an ultrasonic image. With such a configuration, the intravascular diameter d is measured accurately by the intraluminal diameter calculation means 100.COPYRIGHT: (C)2007,JPO&INPIT【課題】血管内腔径dを正確に測定することができる血管内腔径測定装置を提供する。【解決手段】血管内皮機能検査装置(血管内腔径測定装置)30では、超音波プローブ12から超音波を放射したときの動脈血管20からの反射信号SRが検出されると、その反射信号SRに含まれる血管20の管壁からの2群の反射波信号SR1およびSR2に対応する、反射信号SRのうちの2群の反射信号波SR1およびSR2の間の間隔に基づいて血管内腔径dを算出する内腔径算出手段100が備えられている。反射信号SRには微細な強弱の振幅がすべて含まれており、超音波断面画像を表示させるための包絡線処理により消されてしまうような微細な動脈血管の内膜からの2群の反射波の間の間隔に基づいて血管内腔径dが算出されるため、上記内腔径算出手段100により血管内腔径dが正確に測定される。【選択図】 図4
