CT及MRI在直肠癌术前局部分期的临床诊断价值

目的：探讨CT及MRI成像在直肠癌术前分期诊断中的价值．方法对40例直肠癌患者手术前CT及MRI的T、N分期与手术后病理T、N分期结果相对照．结果 CT T分期总的诊断符合率57.5%（31/40），其中 T1～2为87.5%（35/40）， T3为83.25%（33/40）， T4为70%（28/40）， MRI T分期总的诊断符合率77.5%（31/40），其中T1～2为92.5%（37/40），T3为77.5%（31/40），T4为85%（34/40），经检验，CT与MRI在直肠癌各T分期诊断符合率差异无统计学意义（P＞0.05）．CT对各T分期的敏感度T1～2为77.78%（7/9）；T3为75%（12/16）；T4为93.33%（14/15），MRI对各T分期的敏感度T1-2为66.67%（6/9），T3为81.25%（13/16）， T4为80%（12/15），经检验，CT与MRI在直肠癌各T分期诊断敏感性差异无统计学意义（P＞0.05）；CT对各T分期的特异度T1～2为90.32%（28/31），T3为45.83%（11/24），T4为96%（24/25），MRI对各T分期的特异度T1～2为100%（31/31），T3为75%（18/24），T4为88%（22/25），经检验，CT与MRI在直肠癌T3期诊断特异度差异有统计学意义（P＜0.05）；CT N分期总的诊断符合率82.5%（33/40），其中N-为82.5%（33/40）、N＋82.5%（33/40）， MRI N分期总的诊断符合率62.5%（25/40），其中N-为62.5%（25/40）、N＋62.5%（25/40），经检验，CT与MRI在诊断直肠癌盆腔淋巴结有无转移差异有统计学意义（P＜0.05）；CT对N-敏感度83.33%（20/24）、N＋敏感度81.25%（13/16），MRI对N-敏感度75.00%（18/24）、N＋敏感度43.75%（7/16），经检验， CT与MRI在诊断淋巴结阳性敏感度方面差异有统计学意义（＜0.05）；CT对N-特异度81.25%（13/16）、N＋特异度83.33%（20/24），MRI对N-特异度43.75%（7/16）、N＋特异度75.%（18/24），经检验，CT与MRI在诊断淋巴结阴性特异度方面差异有统计学意义（P＜0.05）．结论 MRI在排除肿瘤是否穿透固有肌层达浆膜层的诊断有较高的可靠性；CT在诊断直肠癌淋巴结转移方面更有优势．

A Comparative Study on Diagnostic Value of CT and MRI in Preoperative Local Staging for Rectal Cancer

Objective The purpose of this article was to investigate the diagnostic value of CT and MRI in preoperative local staging for rectal cancer patients. Methods Forty rectal cancer patients were enrolled,and their preoperative CT and MRI staging and pathological staging in T and N were compared. Results The total diagnostic accordance rate of CT staging in T was 57.5%（31/40）,among which the accordance rate of T1-2,T3 and T4 was 87.5%（35/40）,83.25%（33/40） and 70%（28/40）,respectively. The total diagnostic accordance rate of MRI staging in T was 77.5%（31/40）, among which the accordance rate of T1-2, T3 and T4 was 92.5%（37/40）, 77.5%（31/40） and 85%（34/40）,respectively. The differences were tested by Chi-square test,and there were no significant differences between the two groups in T staging. The sensitivity of T staging by CT was 77.78%（7/9） for T1-2, 75% （12/16） for T3 and 93.33% （14/15） for T4. Compared with CT, the sensitivity of MRI was 66.67%（6/9） for T1-2, 81.25%（13/16） for T3 and 80%（12/15） for T4, and there were no significant＆amp;nbsp;differences between the two groups. The specificity of T staging by CT was 90.32% （28/31） for T1-2, 45.83%（11/24） for T3 and 96%（24/25） for T4. Compared with CT, the specificity of MRI was 100% （31/31） for T1-2, 75% （18/24） for T3 and 88%（22/25） for T4, and there was a significant difference in T3 specificity （P 〈0.05） . The total diagnostic accordance rate of CT staging in N was 82.5% （33/40）,among which the rate of N- and N＋was 82.5%（33/40） and 82.5%（33/40）, respectively. The total diagnostic accordance rate of MRI staging in N was 62.5%（25/40）,among which the rate of N- and N＋was 62.5% （25/40） and 62.5%（25/40）, respectively. There were significant differences between the two groups in pelvic N staging （ 〈 0.05） . The sensitivity of N staging by CT was 75.00%for N- （18/24） and 81.25%（13/16） for N＋. Compared with CT,the sensitivity of MRI was 75.00%（18/24） for N- and 43.75%（7/16） for N＋,and there were significant differences between the two groups （ 〈0.05） . The specificity of N staging by CT was 81.25% （13/16） for N- and 83.33%（20/24） for N＋. Compared with CT, the specificity of MRI was 43.75% （7/16） for N- and 75.00%（18/24） for N＋, and there were significant differences between the two groups （ P〈0.05） . Conclusion MRI has a high reliability in diagnosing rectal cancer with penetrating through the muscularis propria into the placenta percreta or not, but CT is superior in diagnosing the lymphonodus metastasis.