MR磁敏感技术对囊性肾癌与复杂性肾囊肿鉴别诊断的价值

目的：探讨MR磁敏感技术对囊性肾癌(cystic renal cell carcinoma， CRCC)与复杂性肾囊肿(complex renal cysts，CRC)鉴别诊断的价值。材料与方法回顾性分析经病理证实的CRCC14例、CRC13例资料，观察两组病变的T1WI、T2WI、增强T2*加权血管成像(enhanced T2 star weighted angiography， ESWAN)序列后处理得到的幅度图中病灶信号变化，应用卡方检验比较两组病变各序列信号变化的差异；由两位观察者分别对两组病变相位图中磁敏感信号(intratumoral susceptibility signal intensity，ITSS)显示情况进行评分，以Kappa检验比较两位观察者评分一致性，以Mann-Whitney U检验比较两组病变相位图ITSS显示的差异；由两位观察者分别测量两组病变相位值、R2*值，使用组内相关系数(intra-class correlation coefficients，ICC)检验两位观察者测量数据的一致性，并应用Mann-Whitney U检验比较两组病变各参数间差异，根据受试者工作特征曲线(receiver operator characteristic curve，ROC)下面积评估相位值、R2*值对CRCC与CRC鉴别的效能，找出相应界值。结果 CRCC与CRC在T1WI、T2WI、幅度图上信号变化的差异无统计学意义(P＞0.05)；两位观察者对两组病变相位图ITSS显示情况评分结果一致性均较好(Kappa＞0.70)，ITSS评分结果CRCC(1.93±1.14)分＞CRC(0.77±1.01)分，差异具有统计学意义(P=0.01)；两位观察者获得两组图像的相位值及R2*值数据结果一致性良好(ICC＞0.75)，CRCC与CRC的相位值及R2*值分别为(－0.030±0.052)与(0.041±0.085)、(28.14±8.26) Hz与(15.99±6.29) Hz，差异均有统计学意义(P＜0.05)；其ROC曲线下面积为分别为0.786、0.885，相位值≤0.010、R2*值≥17.81 Hz为诊断CRCC的界值，两者敏感度、特异度分别为85.7%、69.2%和100.0%、69.2%。结论对常规MR序列难以鉴别的CRCC和CRC，在相位图上CRCC较CRC有更多的ITSS出现；相位值及R2*值可以作为定量指标对两者进行鉴别，且R2*值更具价值。

The value of MR magnetic sensitive technology to identify the cystic renal cell carcinoma and complex renal cysts

Objective: To explore the value of MR magnetic sensitive technology to identify the cystic renal cell carcinoma (CRCC) and complex renal cysts (CRC). Materials and Methods:Fourteen cases of CRCC and thirteen cases of CRC conifrmed by pathology were retrospectively analyzed. The signal performance on T1WI, T2WI, and on magnitude which were generated from enhanced T2 star weighted angiography (ESWAN) data were observed, the Chi-square test was used to compare the difference between each sequence of two groups. The appearance of intratumoral susceptibility signal intensity (ITSS) on the phase map of two groups were observed and scored by two observers,the Kappa test was used to evaluate the consistency of two observers, and the Mann-Whitney U test was used to compare the score difference appearance of ITSS on the phase map of two groups. The values of phase and R2* of two groups were measured by two observers, the data continuity of two groups were measured by the intra-class correlation coefifcients (ICC), and usedthe Mann-Whitney U test to compare various parameters of two groups whether they have statistical difference. Receiver operator characteristic (ROC) curve was used to calculate the cut-off value of phase, R2* and performance of phase, R2* value for distinguishing the CRCC and CRC.Results:The signal performance of CRCC and CRC had no difference on T1WI, T2WI, magnitude map (P>0.05). The consistency of two observers was good (Kappa>0.70), and the score of the appearance of ITSS on the phase map on CRCC (1.93±1.14) was higher than that on CRC (0.77±1.01) (P=0.01). The phase values and R2* values of the two groups obtained from the two observers were in good consistency (ICC>0.70), and the score of the appearance of ITSS on the phase map on CRCC (1.93±1.14) was higher than that on CRC (0.77±1.01) 0.75), the phase and R2* values of CRCC and CRC were -0.030±0.052 and 0.041±0.085, (28.14±8.26) Hz and (15.99±6.29) Hz respectively, the result was statistically signiifcant (P< 0.05). The AUC of phase and R2* values were 0.786, 0.885, the best cut-off values for phase and R2* in characterizing the CRCC from CRC were 0.010 and 17.81 Hz. The sensitivity, specificity were 85.7%, 69.2% and 100.0%, 69.2% respectively.Conclusion:The CRCC and CRC which conventional MR sequences have dififculty to identify, CRCC had more ITSS on phase map. Phase and R2* values can be used as a quantitative index to identify CRCC and CRC, and R2* value is more valuable.