消化管病変に対する3D-EUS診断

Three-Dimensional Endoscopic Ultrasonography in the Diagnosis of Gastorointestinal Diseases

要旨　3D-EUSでは病変を空間的に解析可能である．3D走査は技術の習得，的確な診断，教育面でも効果的である．的確な病変最深部の指摘，リンパ節の同定，有茎性病変の評価が可能となった．消化管病変に対する体腔内3D超音波検査では細径超音波プローブが活用されているが，深達度とリニア方向の走査距離が限定されている．深達度不足に対し3D硬性超音波プローブが試作されているが，専用機による3D-EUSを実現する必要がある．完全摘除生検に対する評価に対してEUSは断層像を内視鏡医自ら確認できる点で有用であり，さらには治療過程の確実性，安全性を高めることが可能と考える．音源情報を3D化し，いかに活用していくかが重要である．

　Three-dimensional（3D）image reconstruction in EUS（endoscopic ultrasonography）enables us to evaluate gastrointestinal diseases spatially. Automatic 3D helical scanning is effective for mastering EUS techniques. The advantage of data obtained by 3D-EUS is that it provides the capability of the accurate diagnosis of lesions. Also 3D-EUS is usefull for education in the use of EUS. 3D manifestation is valuable visually to explore the deepest point of cancer invasion and to distinguish lymph nodes from blood vessels. Arbitrary cross-sectional images in any chosen plane make it possible to observe the junction of the head and stalk of a pedunculated polyp. EUS is useful for determining the indication for endoscopic resection as a total biopsy, and it enhances reliability of diagnosis and safety of treatment for gastrointestinal diseases.

　In 3D intracorporeal ultrasonography for the gastrointestinal tract, 3D-EUS using slim ultrasonic probes is widely used for assessing gastrointestinal diseases. Nevertheless, several existing limitations regarding penetration and scanning stroke in this system must be solved. To resolve limited penetration, a new rectal 3D rigid probe with a 7.5MHz transducer has been developed, which is available for the anorectal region. However, 3D-EUS by means of a conventional echoendscope with an electric scanning transducer, which is fully compatible with 3D functions of conventional ultrasound systems, should be developed to take full advantage of EUS technology.

　Further investigation of clinical practice while demonstrate the potential abilities of 3D-EUS. It is important to make the most of 3D sono-information.