扩散加权成像中表观弥散系数和相对表观弥散系数对乳腺恶性肿瘤的诊断价值

目的 探讨扩散加权成像(DWI)中表观弥散系数(ADC)和相对表观弥散系数(rADC)对乳腺恶性肿瘤的诊断价值.方法 对53例进行乳腺疾病初诊的女性患者的66个病灶,应用单次激发自旋回波-平面回波序列(SE-EPI)进行扫描,在相同的感兴趣区(ROI)下,分别于扩散敏感系数(b)为500和800 s/mm~2.时,测量病灶及同侧远隔部位正常乳腺腺体的ADC值,并计算rADC值.根据受试者工作特性曲线(ROC),确定鉴别乳腺良、恶性病变的最佳ADC和rADC阈值,评价不同b值下,各阈值鉴别诊断乳腺良、恶性病变的敏感度、特异度和准确率.结果 当b值为500 s/mm~2时.良、恶性病灶对应的ADC值分别为(1.71±0.31)×10~(-3)mm~2/s和(1.31±0.38)×10~(-3) mm~2/s,诊断乳腺恶性肿瘤的最佳ADC阈值为1.435×10~(-3)mm~2/s,其诊断的敏感度为82.1%,特异度为81.5%;最佳rADC阈值为0.62,其诊断的敏感度为76.9%,特异度为100%.当b值为800 s/mm.时,良、恶性病灶的ADC值分别为(1.55士0.29)×10~(-3)mm~2/s和(1.14±0.29)×10~(-3)mm~2/s,诊断乳腺恶性肿瘤的最佳ADC阈值为1.295×10~(-3)mm~2/s,其诊断的敏感度为79.5%,特异度为81.5%;最佳rADC阈值为0.71时,诊断的敏感度为89.7%,特异度为88.9%.当b值为800 s/mm~2、rADC的诊断阈值为0.71时,ROC曲线下面积最大.结论 DWI扫描时间短,无需对比剂.ADC和rADC作为诊断指标,其敏感度、特异度均较高,尤其是rADC,对乳腺恶性肿瘤的诊断具有较高的临床应用价值.

Diagnostic value of ADC and rADC of diffusion weighted imaging in malignant breast lesions

Objective The aim of this study was to evaluate the value of diffusion weighten imaging (DWI)in the diagnosis of patients with breast diseases.Methods Fifry-three conecutive patients were scanned with GE signa HDx 1.5 T magmetic resonance system equipped with 8-channel breast coil.DWI was scanned by SE-EPI sequence in b values of 500 s/mm~2 and 800 s/mm~2,respectively.The apparent diffusion coeffcients(ADC)of these lesions were measured.The mean apparent diffusion coefficients(ADC)of these lesions were calculated in b values of 500 s/mm~2 and 800 s/mm~2.respectively.These lesions'ADC value(rAOC)was counted respectively and the result of the rADC was equal to the lesion's ADC divided by the ADC of the ipsilateral normal breast tissue.Threshold of ADC and rADC for differential diagnosis was acquired by ROC(receiver operating characteristic curve) analysis.Different imaging teehnologies were evaluated emphasizing their sensitivity,specificity and accuracy.Results Sixty-six lesions of 53 cases were confirmed by pathology,including 39 malignant lesions and 27 benign lesions.(1)b=500 s/mm~2,the threshold of ADC value was 1.435×10~(-3)mm~2/s,with a sensitivity of 82.1% and a speeificity of 81.5%.The threshold of rADC value was 0.62,with a sensitivity of 76.9% and a specificity of 100%.(2)b= 800 s/mm~2,the threshold of ADC value waft 1.295 × 10~(-3)mm~2/s,with a sensitivity of 79.5%and a specificity of 81.5%.The threshold of rADC value was 0.71,with a sensitivity of 89.7% and specificity of 88.9%.(3)The area under the ROC cirve was increased for the four diagnostic indicators(ADC_(500),ADC_(800),rADC_(500),rADC_(800)).Condusion DWI spends short time,and it doesn't need contrast material.ADC value and rADC value have a high sensitivity and specificity as a diagnostic indicator.DWI is helpfulin improving the specificity of MR and may become one of valuable conventional procedures for breast tumor diagnosis.