通常内視鏡下pit観察による大腸腫瘍・非腫瘍鑑別能の検討―5mm以下の病変を対象として

Differential Diagnosis of Colonic Neoplasm from Non-neoplasm (＝5 mm) in Pit Pattern Observation by Conventional Colonoscopy

要旨　通常内視鏡下pit観察による大腸病変の腫瘍・非腫瘍鑑別（質診断）能の評価を目的として，5mm以下の411病変を対象に内視鏡の機種，色素撒布の有無，肉眼形態別の質診断能の検討を行い，以下の結果を得た．①通常内視鏡（CF-Q240I，CF-230I）ではコントラスト法による正診率（82.2％，87.7％）が色素撒布なしの通常観察による正診率（59.0％，60.3％）より有意に高かった（p＜0.0001，p＜0.0005）．また，2機種間に正診率の有意差は認めなかった．②腫瘍性病変の正診率が非腫瘍性病変の正診率より高かった．③隆起型病変のpit pattern判定不能率が表面型病変のpit pattern判定不能率より低かった．④拡大内視鏡（CF-Q240Z）と通常内視鏡の正診率に有意差は認められず，拡大観察での質診断能を高めるためにはピオクタニンなどによる染色法の必要性が示唆された．

　Colonic pit pattern observation by conventional colonoscopy was performed on 411 lesions, sized less than 5 mm, to study its diagnostic ability to differentiate colonic neoplasm from non-neoplasm. Type of endoscope, dye-spray method and macroscopic type of lesion were also investigated for their effect on qualitative diagnostic accuracy.

　The following results were obtained: 　1) Accurate diagnostic rates by CF-Q240I and CF-230I with the dye-spray contrast method were 82.2％ and 87.7％ respectively, while these rates were 59.0％ and 60.3％ without the dye-spray contrast method. Dye-spray contrast method was significantly effective (p＜0.0001 and p＜0.0005) in the differential diagnosis of neoplasms from non-neoplasms. However, no significant difference was noted between the results of the two types of endoscope.

　2) Accurate diagnostic rate was higher in neoplastic lesions than that in non-neoplastic lesions.

　3) Pit pattern on elevated type lesions was less well diagnosed than that on superficial type lesion.

　4) No significant difference in diagnostic accuracy was noticed between a magnifying colonoscope (CF-Q240Z) and a conventional colonoscope. To raise the diagnostic accuracy of the magnifying endoscope, dye-spray stain method (ex. pioctanine) was regarded as mandatory.