子宫内膜癌和正常子宫扩散加权成像信号强度与ADC值关系的研究

Relationship between apparent diffusion coefficient and signal intensity in normal uterus and endometrial carcinoma

目的分析正常子宫MR图像三层结构(内膜、结合带、外带)在扩散成像上的各自特点,探讨子宫正常结构的扩散信号强度与表观弥散系数(ADC)值关系,以及扩散成像是否有助于区别子宫内膜癌(EC)病灶与正常子宫内膜。方法正常子宫组16例,EC组14例,进行常规MRI扫描及横断面扩散成像扫描(b=1000s/mm2)。测量正常子宫三层结构和子宫内膜癌病灶的扩散信号强度,分别计算ADC值,进行比较。结果正常子宫三层结构的扩散图像信号强度有差异,内膜信号最高,外带最低,结合带与外带的差异肉眼不能分辨。三者ADC值有显著性差异,外带[(1.67±0.187)×10-3mm2/s]>内膜[(1.36±0.210)×10-3mm2/s)]>结合带[(1.13±0.128)×10-3mm2/s)]。扩散图像正常子宫内膜与EC病灶信号强度无明显差异,ADC值差异有显著性,内膜[(1.36±0.210)×10-3mm2/s]高于EC病灶[(0.89±0.137)×10-3mm2/s]。结论正常子宫三层结构MR扩散能力存在较明显差异,内膜扩散信号强度最高,结合带ADC值最低。扩散加权图像有利于突出显示子宫内膜癌病灶。ADC值测量对于扩散图像信号与正常子宫内膜相仿的子宫内膜癌病灶有一定鉴别价值。

Objective To investigate the relationship between apparent diffusion coefficient （ADC） value and signal intensity in diffusion-weighted imaging （DWI） of normal uterus, and to evaluate the application of DWI in endometrial carcinoma （EC）. Methods Routine MRI sequences and axial diffusion weighted sequences （b= 1000 s/mm^2） were performed in 14 patients with EC and 16 female with normal uterine as control. The signal intensity and ADC values were measured and ana- lyzed. The differences in three layers of normal uterine and ECs were compared. Results There was statistically significant difference in signal intensity of the three layers of normal uterus in diffusion-weighted images, with endometrium the highest, outer myometrium the lowest. The difference between junctional zone （JZ） and outer myometrium could not be identi- fied by naked eyes. ADC values also had statistically significant difference, with outer myometrium the highest, JZ the lowest. Though the signal intensity between normal endometrium and loci of EC showed no difference, ADC values of endome- trium was much higher than that of EC. Conclusion The three layers of normal uterus have different diffusion characteristics. DWI take the advantages of easily identifying loci of endometrial carcinoma, and ADC values provide certain help in differentiating between endometrial carcinoma and normal endometrium.