대한대장항문학회

Transrectal ultrasonography(TRUS) has been well-recognized as an useful method to<br>assess the preoperative staging for rectal carcinoma by measuring the depth of tumor<br>invasion through the rectal wall layers and the status of pararectal lymph node<br>involvement. Authors conducted a comparative study between TRUS and CT scan for<br>the preoperative staging of rectal carcinoma. Eighty-two patients were examined by<br>TRUS and 56 by CT scan. The depth of tumor invasion was divided into<br>four<br>ultrasonographic levels(T<sub>1</sub>∼T<sub>4</sub>) according to UICC<br>T<br>classification, and into two CT scan findings(confined or beyond rectal wall) according<br>to Astler-Coller classification. The results of these preoperative assessments were<br>confirmed by the postoperative histopathologic findings.<br>Depth of the tumor invasion was correctly diagnosed in 73 of 82 cases(89.0% ) by<br>TRUS and 42 of 56 cases(75.0%) by CT scan. TRUS predicted perirectal tumor growth<br>with a sensitivity of 90.5%, specificity of 94.7%, positive predicted value(PPV) of 98.3%<br>and NPV of 75.0%, whereas the corresponding figures for CT scan were 77.3%, 66.7%,<br>89.5% and 44.4%. Perirectal lymph node metastasis of the tumor was correctly diagnosed<br>in 53 of 75 cases(70.7% ) by TRUS and 38 of 51(74.5%) by CT scan. TRUS predicted<br>perirectal lymph node metastases with a sensitivity of 68.9%, Specificity Df 73.3%, PPV<br>Of 79.5% anti NPV Of 61.1%, Whereas the Corresponding fixtures for CT scan were<br>86.2%,59.1%,73.5% and 76.5%.<br>Authors concluded that TRUS was more effective staging method than CT scan in<br>the assessment of the local tumor growth through the rectal wall(P<0.01).<br>TRUS and CT scan could detect perirectal lymph-node enlargement but could not be<br>exactly assessed perirectal lymph-node metastasis.<br>