前列腺MR动态增强扫描感兴趣区的选择方法的探讨

Discussion on method selection of region of interest during prostate dynamic contrast-enhanced MR imaging

目的：探讨感兴趣区（ROI）不同对MR动态增强扫描（DCE-MRI）时间-信号强度曲线（TIC）的影响及价值。材料与方法：99例病人均行前列腺动态增强扫描,共118个前列腺周围带病灶,其中良性病变63个,前列腺癌55个。在动态增强扫描图像上,分别获取病灶中心层面1个大ROI（20~150 mm^2）及分散在病灶内13个小ROI（6.6 mm^2）的TIC,比较大、小ROI的TIC在良恶性前列腺病灶中的差异。采用两种方案分类病灶TIC类型并分别进行DCE-MRI的PI-RADS评分：方案1：病灶曲线类型为大ROI曲线类型;方案2：病灶小ROI中有3型曲线者,病灶曲线类型归为3型,没有者归为大ROI曲线类型。结果：病灶中,具有大ROI曲线类型的小ROI数的中位数,良性病变12,前列腺癌10,中位数检验P=0.003。两种方案诊断前列腺癌,方案1敏感性76.36%,特异性90.48%,方案2敏感性87.27%,特异性85.71%,敏感性比较P=0.031,特异性比较P=0.250。结论：前列腺癌灶各处强化方式多不完全一致,采用小ROI寻找3型曲线区域,有助于周围带前列腺癌的诊断。

Objective： To discuss the influence of different regions of interest （ROI） on the time-intensity curve （TIC） and its value during dynamic contrast-enhanced MRI （DCE-MRI）. Method： Prostate DCE-MRI was performed on all the 99 pa- tients. There were 118 lesions in the peripheral zone, including 55 benign lesions and 63 prostate cancers. On dynamic con- trast-enhanced MRI, the TIC of a large ROI（20~150 mm2） on the central layers of the foci and 13 small ROIs（6.6 mm2） scat- tering inside the foci were obtained. The difference between the TICs of the large and small ROIs in the benign and malig- nant prostate foci was compared. Two protocols were adopted to classify the TIC of the foci, and then PI-RADS score to DCE-MRI was carried out respectively. Protocol 1： The type of curve was big ROI curve. Protocol 2： The type of curve was type 3 curve if there was such a curve in any .small ROI. Otherwise, it was regarded as a large ROI curve. Result： The me- dian number of small ROIs with the type of big ROI curve in the foci was 12 for the benign lesions and 10 for the prostate cancer. The median test result was P=0.003. For diagnosis of prostate cancer, the sensibility and specificity of Protocol 1 were 76.36% and 90.48%, while the sensibility and specificity of Protocol 2 were 87.27% and 85.71%（P=0.031 and P=0.250 re- spectively）. Conclusion： Enhancement at different ROIs of the foci of prostate cancer did not go all the same way. It is help- ful for the diagnosis of prostate cancer in the peripheral zone to adopt small ROIs to seek type 3 curve.