Ⅰp・Ⅰsp型大腸癌の深達度診断―超音波内視鏡を中心として

Effectiveness of High-frequency Ultrasound Probes for Diagnosis of Invasion Depth of Pedunculate or Subpedunculate Types of Colorectal Cancers

要旨　高周波超音波細径プローブ（HFUP）を施行した166病変を対象として，Ⅰp・Ⅰsp型大腸癌におけるHFUPの深達度診断能について検討した．①Ⅰp・Ⅰsp型大腸癌におけるHFUPの深達度正診率は71.9％，判定不能例を除けば79.3％であり，表面型に比べ低率であった．②HFUPの深達度誤診の主な原因は超音波の深部減衰であった．③Ⅰp・Ⅰsp型大腸癌におけるHFUPの深達度正診率は，内視鏡検査（75％），X線検査（78.3％）の正診率と同等であった．④内視鏡検査と比較してHFUPでは，sm_2,3癌に対する深達度診断精度が高く，特に粘膜内病変が残存するsm浸潤癌の診断に有用であった．

　To elucidate the usefulness of high-frequency ultrasound probes (HFUP) in diagnosis of invasion depth of pedunculate or subpedunculate types of colorectal cancers, 166 lesions were analyzed. The results were as follows : 1) Diagnostic accuracy of invasion depth by HFUP was 71.9% in pedunculate or subpedunculate lesions, 67.6% in sessile lesions and 88.0% in superficial lesions. 2) In many of the misdiagnosed cases of pedunculate or subpedunclate type of colorectal cancers, advanced parts of invasion were poorly visualized by HFUP due to the attenuation of ultrasound. 3) Diagnostic accuracy of invasion depth by colonoscopy or radiography was the same as that by HFUP and 4) Diagnostic accuracy by HFUP in moderately or massively extended submucosal cancers is higher than that detained by colonoscopy. HFUP was especially useful for the invasion-depth diagnosis of submucosal cancers without mucosal lesions. In conclusion, HFUP is useful for the diagnosis of invasion depth of pedunculate or subpedunculate types of colorectal cancers which haven't been diagnosed with centainty by colonoscopy.