蜂屋 弘之

Hiroyuki HACHIYA

東京工業大学工学院システム制御系

School of Engineering, Department of Systems and Control Engineering, Tokyo Institute of Technology

キーワード : Rayleigh distribution, liver fibrosis, numerical simulation, quantitative diagnosis, speckle pattern

超音波Bモード画像は，組織中の散乱体分布変化の影響を受ける．病変組織の連続的な変化，特に初期病変の情報を臨床的に取得することが困難なため，超音波画像と組織構造の関係を評価するのは簡単ではない．本総説では，組織の音響的構造を考慮した散乱波シミュレーションの手法について述べる．ここで述べるモデル化手法は，正常およびびまん性肝疾患の散乱体分布を結節や線維構造を含め表現できる．この散乱体分布を用いて得られるBモード画像を用いて，生体組織の変化とBモード画像の変化の関係について解析することができる．

Ultrasonic B-mode images are affected by changes in scatterer distribution in tissue. It is hard to estimate the relationship between the ultrasonic image and the tissue structure quantitatively because we cannot observe the continuous stages of diseased tissue clinically, particularly the beginning stage. In this review, a simulation method of scattering echo that takes into account tissue acoustic structure is presented. The modeling method of scatterer distribution for normal and diffuse diseased livers can determine the expansion of nodules and fibers. Using B-mode images obtained from these scatterer distributions, we can analyze the relationship between the changes in the form of biological tissue and changes in the B-mode images during progressive liver cirrhosis.