眼眶肿块的MR扩散加权成像研究

Investigation of Orbital Masses with Diffusion-Weighted MR Imaging

目的评价表现扩散系数(ADC)值对眼眶不同类型肿块的诊断与鉴别诊断价值。资料与方法65例眶内肿块病例行常规MRI及扩散加权成像(DWI)扫描。分别测量病变兴趣区及对侧颞叶脑白质ADC值,比较不同类型眼眶病变ADC差别。结果65例眶内肿块的ADCM为(1.38±0.55)×10-3mm2/s,ADCw为(0.85±0.07)×10-3mm2/s。其中淋巴造血系肿瘤ADCM为(0.76±0.12)×10-3mm2/s;癌ADCM为(1.36±0.39)×10-3mm2/s;良性实性肿块ADCM为(1.35±0.54)×10-3mm2/s;脉管性肿块ADCM为(1.50±0.30)×10-3mm2/s;囊性肿块ADCM为(1.92±0.99)×10-3mm2/s。不同组间眼眶肿块ADCM差异有统计学意义(P<0.05),其中淋巴造血系肿瘤ADCM显著低于癌、良性实性肿块、脉管性肿块、囊性肿块(P<0.01);癌、良性实性肿块ADCM显著低于囊性肿块(P<0.05);癌、良性实性肿块与脉管性肿块之间ADCM差异无统计学意义(P>0.05),脉管性肿块与囊性肿块ADCM差异无统计学意义(P>0.05)。结论DWI可反映眼眶肿块的扩散特征,不同类型眶内肿块ADC值之间具有差异,有助于病变的鉴别诊断。

Objective To evaluate the diagnostic value of apparent diffusion coefficient in various orbital lesions. Materials and Methods Sixty-five cases with orbital masses who underwent conventional MRI and diffusion imaging were studied by using 1.5T magnetic resonance system. All cases were divided into five groups according to their histopathologic results. Quantitative ADC of masses（ADCM ） and of the white matter of contralateral temporal lobe （ADCW） were measured. All cases were proved by histopathology. Results The mean ADCM of 65 cases was （ 1.38 ±0.55） ×10^-3mm^2/s and the mean ADCw was （0.85 ±0.07） ×10^-3mm^2/s. The mean ADCM of lymph-hematopoiesis tumor,carcinomas,benign solid tumors, benign vascular anomalies and benign cystic masses were （0.76 ± 0. 12） ×10^-3mm^2/s, （ 1.36 ± 0.39 ） ×10^-3mm^2/s, （1.35 ± 0.54）×10^-3mm^2/s, （1.50 ±0.30） ×10^-3mm^2/s and （1.92 ±0.99 ） ×10^-3mm^2/s. The mean ADCM of lymph-hematopoiesis tumor was smaller （P 〈 0.01 ） than that of carcinomas, benign solid tumors, benign vascular anomalies and benign cystic masses. The mean ADCM of carcinomas and benign solid tumors was smaller （ P 〈 0.05 ） than that of benign cystic masses. However no significant difference was seen （P 〉 0.05 ） among the mean ADCM of carcinomas, benign solid tumors and benign vascular anomalies. There was no significant difference （P 〉 0.05 ） between ADCM of benign vascular anomalies and of benign cystic masses. Conclusion Diffusion MR imaging and ADC value could reveal the diffusion characteristic of orbital masses and provide additional information for conventional magnetic resonance imaging in distinguishing different orbital masses.