NBIによる大腸内視鏡スクリーニング

Screening Colonoscopy Using Narrow Band Imaging System

要旨　NBI（narrow band imaging）の特徴は，内視鏡の観察光の分光特性を狭帯域特性へ変更し（短波長側にシフト），病変の視認性や表面微細構造，微細血管観察の向上を可能にしたことにある．現時点でNBIが大腸内視鏡スクリーニング検査における有用性が検討されているのは以下の3項目である．（1）発見率の向上（報告がcontroversialでありさらなる検討が必要）．（2）腫瘍/非腫瘍の鑑別（optical/digital chromoendoscopyとして色素を使用せずに可能）．（3）大腸腫瘍の腺腫/癌の質的診断（深達度に関する量的診断に関しては今後の課題）．今後は微細血管（構造）分類のvalidation study，inter-intra observer variability，learning curveなどの関係を明らかにする必要があろう．

　NBI（narrow band imaging）is a technique that modifies endoscopic observational spectroscopy to a narrow band range（shift to shorter wavelength）, which permits enhancement of lesions and allows visualization of the fine structure of the mucosal surface or microvessels. NBI is useful for colonoscopic screening examination as it has a higher lesion detection rate than traditional methods ; however, further studies are required because contrary results have also been reported. NBI can distinguish between neoplasia and non-neoplasia（optical/digital chromoendoscopy without the use of dyes）. In addition, this method showed superior ability to discriminate between colonic cancer and adenoma（Further studies are required for determination of the depth of the lesions）. Further investigations are required to verify the correlation with classification for capillaries（structures）and validation study, inter-and intraobserver variability, and learning curve should be examined in future.