MRI在急性单纯性阑尾炎中的诊断价值

MRI Diagnosis of Simple Acute Appendicitis

目的:探讨MRI在急性单纯性阑尾炎中的诊断价值。方法:16只经手术和病理证实为急性单纯性阑尾炎及18只经手术和病理证实为正常阑尾的新西兰大白兔先后进行MSCT和MRI检查。在MSCT及MRI图像上分别测量阑尾腔内液体的最大直径(MDIAF)。以b值为800 s/mm^2的扩散加权成像(DWI)图像上阑尾壁信号最高的部位为参考,在ADC图像上相应的感兴趣区(ROI)部位测量ADC值。绘制MDIAF、阑尾壁ADC值诊断急性单纯性阑尾炎的ROC曲线,计算敏感度、特异度、准确度和曲线下面积。MSCT与MRI采用MDIAF诊断急性单纯性阑尾炎ROC曲线下面积的比较采用卡方检验。结果:MSCT采用MDIAF诊断急性单纯性阑尾炎的敏感度、特异度、准确度分别为87.50%(14/16)、83.33%(15/18)、85.29%(29/34),ROC曲线下面积为0.85。MRI采用MDIAF诊断急性单纯性阑尾炎的敏感度、特异度、准确度分别为87.50%(14/16)、77.78%(14/18)、82.35%(28/34),ROC曲线下面积为0.87。MSCT与MRI采用MDIAF诊断急性单纯性阑尾炎ROC曲线下面积的比较无统计学差异(χ2=0.17,P=0.68)。当阑尾壁ADC值为0.97×10-3mm^2/s时,诊断急性单纯性阑尾炎的敏感度、特异度、准确度分别为81.25%(13/16)、83.33%(15/18)、82.35%(28/34),ROC曲线下面积为0.84。结论:MRI在诊断急性单纯性阑尾炎方面具有较高的诊断价值,可以广泛用于腹痛疾病的鉴别诊断,尤其是孕妇及儿童群体。

Purpose： To investigate the value of magnetic resonance imaging （MRI） in diagnosing simple acute appendicitis （SAA）. Methods： Sixteen New Zealand white rabbits, which were confirmed with SAA by pathology results and surgery, and 18 New Zealand white rabbits, which were confirmed with normal appendix by pathology results and surgery were undergone multi-slice CT （MSCT） and MRI examination in order. Maximum depth of the intraluminal appendiceal fluid （MDIAF） was measured respectively on MSCT and MRI . Using the highest intensity area of appendiceal wall as reference on diffusion weighted imaging （DWI）, whose b value was set as 800 s/mm^2, a region of interest （ROI） was placed at the same localization on the ADC map. Based on the data of MDIAF and ADC value of the appendiceal wall, receiver operating characteristic （ROC） curves were constructed and used to obtain cutoff values that best differentiated SAA from normal appendix. The sensitivity, specificity, accuracy and area under ROC curves were calculated respectively. For the area under ROC curves of MDIAF between MSCT and MRI for diagnosing SAA, the Chi-square test was performed. Results： Based on the data of MDIAF, the sensitivity, specificity, accuracy and area under ROC curves of MSCT for diagnosing SAA were 87.50%（14/16）, 83.33%（15/18）, 85.29%（29/34） and 0.85, respectively; the sensitivity, specificity, accuracy and area under ROC curves of MRI for diagnosing SAA were 87.50%（14/16）, 77.78%（14/18）, 82.35%（28/34） and 0.87, respectively. No statistical significant difference was found in area under ROC curves of MDIAF between MSCT and MRI （X^2=0.17, P=0.68）. Using the ADC value of 0.97 × 10^3mm^2/ s of appendiceal wall as the cutoff value for SAA, the sensitivity, specificity, accuracy and area under ROC curves for diagnosing SAA were 81.25%（13/16）, 83.33%（15/18）, 82.35%（28/34） and 0.84, respectively. Conclusions： MRI is very useful for the diagnosis of SAA. MRI can be widely used in the differential diagnosis of abdominal pain, especially in oremaant women and children.