体素内不相干运动双指数模型评价乳腺肿块样病变

目的 应用体素内不相干运动(IVIM)双指数模型探讨真性弥散系数(D)、与灌注相关的假性弥散系数(D^*),灌注分数(f)在诊断乳腺肿块样病变诊断中的应用价值。方法 收集经病理证实的乳腺恶性肿块48例(恶性组)、良性肿块26例(良性组)及正常体检者19名(对照组),均行常规MRI检查及多b值的弥散加权成像检查。比较3组间D值、f值、D^*值及ADC值的差异,采用ROC曲线评估各个指标对乳腺良恶性肿块样病变的诊断效能。结果 对照组、良性组及恶性组间D、f、D^*及ADC值的差异均有统计学意义(P均<0.01)。良性组D值低于对照组、且高于恶性组(P均<0.01);恶性组f值高于对照组及良性组(P均<0.01),而对照组与良性组间差异无统计学意义(P=0.14);良性组D^*值低于对照组、高于恶性组(P均<0.01);良性组ADC值低于对照组、高于恶性组(P均<0.01)。恶性组的D值显著低于ADC值(P<0.01)。分析采用各DWI参数鉴别诊断乳腺恶性肿块样变的ROC曲线,D值具有较高的诊断效能,其次依次为ADC值,f值及D^*值,曲线下面积(AUC)依次为0.95、0.90、0.87、0.75。结论 IVIM双指数模型能够真实反映乳腺肿块样病变水分子的弥散情况,尤其是D值对乳腺病变良恶性的鉴别诊断具有重要的参考意义。

Biexponential model of intravoxel incoherent motion in diagnosis of breast mass

Objective To explore the value of diffusion coefficient (D), pseudo diffusion coefficient(D^*), perfusion fraction (f) with biexponential model of intravoxel incoherent motion (IVIM) in diagnosis of breast mass. Methods Totally 48 cases of malignant breast tumors (malignant group), 26 cases of benign tumors (benign group) and 19 normal subjects (control group) underwent conventional MRI and DWI with multi-b values. The D, D^*, f and ADC value were compared among 3 groups, and the efficiency in diagnosis of benign and malignant breast neoplasms were analyzed by ROC curve. Results There were statistical differences among the control group, benign and malignant groups in D, f, D^* and ADC values (all P<0.01). D values in benign group lower than that in control group, and higher than that in malignant group (both P<0.01). The f values in the malignant group were the highest (both P<0.01), and between the control group and the benign group, the difference was not statistically significance (P=0.14). D^* values in benign group lower than that in control group, and higher than the maligant group (both P<0.01). ADC values in benign group lower than that in control group, and higher than that in maligant group (both P<0.01). The D values was significantly lower than ADC values in malignant tumor (P<0.01). Comparison of ROC curve, the diagnosis efficiency is highest using the D values, followed by the ADC value, f value and D^* value, and area under the curve were 0.95, 0.90. 0.87 and 0.75. Conclusion Biexponential model of IVIM can reflect the true water diffusion motion. The values of D is important reference for the differential diagnosis of benign and malignant breast masses.