剖検試料を用いた病変肝エコー特性解析法の評価(医用超音波)  [in Japanese] Estimation of Tissue Characterization Method by Echo Information using Autopsy Specimen of Cirrhotic Liver  [in Japanese]

本研究では,エコー信号の振幅特性を用いた組織性状診断法を確立するために,生体組織の音響特性と組織の物理的・化学的構造変化の関係を考慮し,複数のアプローチで検証を行っている。生体から摘出した6例の硬変肝剖検試料を対象とし,水槽実験において収集した200枚のエコー信号において非レイリー分布となる情報のみを抽出し,3次元構造を構築した結果,複数の線状の構造物が確認された。また,エコー信号を収集後に組織切片を作成し,超音波顕微鏡を用いて生体音響特性(音速・減衰)を計測した結果,正常肝及び結節組織に比較して線描組織では分散が大きいことが確認された。生体組織構造を詳細に把握するために,剖検試料から複数の病理組織写真を作成し,染色情報を元に線維組織構造を3次元で再構築し,エコー信号の処理結果及び生体音響特性の計測結果と比較したところ,エコー信号から得られた線状の構造物及び減衰が大きい部位が繊維部であることが確認された。

This paper presents tissue characterization method for cirrhotic human liver tissue using acoustical and biological characteristics. The first approach is a statistical processing technique of echo amplitude. RF echo signals from 6 in vitro samples of human cirrhotic liver were obtained using ultrasonic (US) diagnostic equipment. Our processing technique extracts the echo information that does not obey a Rayleigh distribution. In the 3D image of each liver which were constructed with extracted echo information from 200 tomograms, many thin structures can be seen clearly. The second approach is measurement of the attenuation and US velocity. Estimated Attenuation and US velocity of normal and necrotic tissues had small dispersion, however, results of fiber tissues distributed widely. We inspected in detail about above results using stained pathological tissue sections. A particular color component was extracted from each stained paraffin section, and the 3D fiber structure constructed from extracted color information. The volumetric structures of fibrotic tissues can be confirmed clearly, and they agreed with the extracted echo information using statistical processing and the regions which have the especially large attenuation.