表观扩散系数在中脑脚间区扩散高信号与急性脑梗死中的鉴别诊断价值

Apparent Diffusion Coefficient Value in the Differentiation of Interpeduncle Region(IPR) of Normal Midbrain with High Signal from IPR with Acute Infarction on Diffusion-Weighted Imaging

目的探讨表观扩散系数(ADC)在中脑脚间区扩散高信号与急性脑梗死鉴别诊断中的价值。方法回顾性分析经临床证实的中脑脚间区急性脑梗死31例(病例组)、健康受检者31例(对照组,中脑脚间区在DWI上呈高信号)。均行常规MRI及DWI。由两名医师先采用双盲法独立对图像进行评估,并采用组内相关系数(ICC)值分析两名医师测量ADC值的一致性。计算两名医师测量ADC值的平均值,并采用独立样本t检验比较病例组与对照组ADC值的差异。以临床结果为金标准绘制ADC值诊断中脑脚间区急性脑梗死的ROC曲线,判断最佳诊断界值点,计算ADC值诊断中脑脚间区急性脑梗死的敏感性、特异性和准确性。结果两名医师测量ADC值的一致性好(ICC=0.926,P<0.001)。对照组ADC值为(635.69±54.16)×10^(-6)mm^2/s(95%可信区间为615.83~655.56×10^(-6)mm^2/s),病例组ADC值为(472.08±87.65)×10^(-6)mm^2/s(95%可信区间为439.93~504.23×10^(-6)mm^2/s),差异有统计学意义(t=8.842,P=0.000)。ADC值诊断中脑脚间区急性脑梗死的ROC曲线下面积为0.935,最佳诊断界值为546×10^(-6)mm^2/s,诊断中脑脚间区急性脑梗死的敏感性为87.1%(27/31),特异性为93.5%(29/31)淮确性为90.3%(56/62)。结论 ADC值有助于中脑脚间区扩散高信号与急性脑梗死的鉴别。

Objective To explore the value of apparent diffusion coefficient（ADC） in the differentiation of interpeduncle region（IPR） of normal midbrain with high signal from IPR with acute infarction on diffusion-weighted imaging（DWI）.Methods Patients with clinical proven acute infarction in the IPR（n = 31） and an aged matched control group（n = 31）were retrospectively analyzed.Conventional MRI and diffusion-weighted imaging were performed.Two radiologists who were blinded to the clinical data quantitatively analyzed the ADC values of suspicious lesions independently.Inter-reader agreement for ADC values was assessed with intra-class correlation coefficient（ICC）.Difference of ADC values in two groups was assessed by students t-test.Receiver operating characteristic curve（ROC） was used to determine the best predictor and cutoff value.Based on optimal cut-offs,the sensitivity,specificity,accuracy were calculated.Results The ICC was high（ICC= 0.926）.The mean ADC value of normal IPR with high signal was higher than IPR with acute infarction on DWI（t = 8.842,P =0.000）,（635.69±54.16）×10-3 mm2/s and（472.08 ±87.65）×10-3mm2/s,respectively.Diagnostic cutoff point was 546 × 10-3 mm2/s,areas under the curves（AUC） 0.935,diagnostic sensitivity 87.1%（27/31）,specificity 93.5%（29/31）,accuracy 90.3%（56/62）.Conclusion ADC value is valuable in the differential diagnosis of normal IPR with high signal from IPR with acute infarction on DWI.