ADC在脊索样脑膜瘤鉴别诊断中的价值

Apparent Diffusion Coefficient in Differential Diagnosis of Chordoid Meningiomas

目的探讨扩散加权成像(DWI)、表观扩散系数(ADC)值在脊索样脑膜瘤(CM)和其他亚型脑膜瘤鉴别诊断中的价值。方法搜集本院经手术病理证实的45例脑膜瘤患者(其中CM 10例,WHOⅠ级脑膜瘤患者22例,WHOⅡ级非典型脑膜瘤9例,WHOⅢ级横纹肌样脑膜瘤3例和乳头样脑膜瘤1例)的常规MRI平扫、增强及DWI资料,然后测量肿瘤实质区的ADC、r ADC值,比较CM与其他亚型脑膜瘤的ADC、r ADC值差异,并运用受试者工作特征曲线(ROC)评价ADC、r ADC值的诊断价值。分别对CM和其他3个级别脑膜瘤的平均ADC值和r ADC值进行独立样本t检验。结果 10例CM、22例WHOⅠ级脑膜瘤、9例WHOⅡ级非典型脑膜瘤、4例WHOⅢ级脑膜瘤(横纹肌样脑膜瘤3例,乳头状脑膜瘤1例)的平均ADC值分别为(1.20±0.35)×10^(-3)mm^2/s、(0.83±0.11)×10^(-3)mm^2/s、(0.73±0.16)×10^(-3)mm^2/s、(0.69±0.13)×10^(-3)mm^2/s,平均r ADC值分别为1.57±0.48、1.12±0.18、1.03±0.10、0.98±0.23,其差异均有统计学意义(P<0.01)。ADC值和r ADC值诊断CM的ROC曲线下面积(AUC)分别为0.914±0.055和0.889±0.600,以0.903×10^(-3)mm^2/s和1.32为阈值时,诊断CM的灵敏度和特异度分别为90%与88.6%、80%与94.3%。结论 CM的ADC值和r ADC值高于其他亚型的脑膜瘤,有助于CM和其他亚型脑膜瘤的鉴别诊断,提高CM术前诊断的准确率。

Objective To explore the value of conventional MRI and apparent diffusion coefficient（ADC） value in differential diagnosis of chordoid meningiomas （CM） and other meningioma subtypes. Methods 45 MR images of meningiomas（ CM for 10 cases, atypical meningioma of WHO grade Ⅱ for 9 cases, Rhabdoid meningioma and papillary meningioma of WHO grade Ⅲ for 3 cases and 1 cases , respectively. ） confirmed by pathology were retrospectively analyzed in this study. Conventional, post-contrast and diffusion weighted MR scans were performed in all patients . The average ADC value and relative ADC （rADC） were calculated in the solid component of the tumors. The ADC values and rADC values between CM and other meningioma subtypes were compared separately. The receiver operating characteristic curves （ROC）were constructed to assess the diagnostic value of ADC and rADC. Two sample t-test were used to analyze average ADC values and rADC ratios between CM and other meningioma subtypes. Results The ADC value and rADC ratio were, respectively, 1.20 ± 0.35 ） × 10^-3 mm2/s and 1.57 ± 0.48 in CM, （0.73± 0.16） ×10^-3 mm2/s and 1.03 ± 0.10 in WHO grade II atypical meningioma, （0.83 ±0.11） ×l0^-3mm2/s and 1.12 ±0.18 in benign WHO grade I meningiomas, （0.69 ±0.13） × 10^-3 mm2/s and 0.98 ± 0.23 in WHO grade III meningiomas. Statistical analyses of the average ADC values and relative ADC （rADC） ratios revealed a statistically significant difference between CM and all other WHO grade Ⅰ , Ⅱ , and Ⅲsubtypes （ P 〈 0.01 ）. The areas under the ROC curves of ADC and rADC diagnosing CM were 0. 914 ± 0. 055 and 0. 889 ± 0. 600, and by using optimal cut point of 0.903 × 10^-3 mm2/s and 1.32 for ADC and rADC of the lesion, the sensitivity and specificity were 90% and 88.6% ,80% and 94.3 %, respectively. Conclusion CM have statistically significant elevations of ADC and rADC values compared with all other WHO grade Ⅰ , Ⅱ , and m subtypes, which increases reliable preoperative prediction of CM and helps make reasonable surgical planning.