Department of Radiology, Guangdong Academy of Medical Sciences/Guangdong General Hospital, GuangZhou, Guangdong Province, PR China; Southern Medical University, GuangZhou, Guangdong Province, PR China.
Eur J Radiol. 2013 Dec;82(12):e782-9. doi: 10.1016/j.ejrad.2013.08.006. Epub 2013 Aug 13.
To obtain perfusion as well as diffusion information in normal breast tissues and breast lesions from intravoxel incoherent motion (IVIM) imaging with biexponential analysis of multiple b-value diffusion-weighted imaging (DWI) and compare these parameters to apparent diffusion coefficient (ADC) obtained with monoexponential analysis in their ability to discriminate benign lesions and malignant tumors.
In this prospective study, informed consent was acquired from all patients. Eighty-four patients with 40 malignant tumors, 41 benign lesions, 30 simple cysts and 39 normal breast tissues were imaged at 1.5 T utilizing contrast-enhanced magnetic resonance imaging (MRI) and DWI using 12 b values (range: 0-1000 s/mm(2)). Tissue diffusivity (D), perfusion fraction (f) and pseudo-diffusion coefficient (D*) were calculated using segmented biexponential analysis. ADC (b = 0 and 1000 s/mm(2)) was calculated with monoexponential fitting of the DWI data. D, f, D* and ADC values were obtained for normal breast tissues, simple cysts, benign lesions and malignant tumors. Receiver operating characteristic analysis was performed for all DWI parameters.
There was good interobserver agreement on the measurements between the 2 observers. D values were significantly different among malignant tumors, benign lesions, simple cysts and normal breast tissues (P = 0.000) and it was the same result for f, D* and ADC values. Further comparisons of these 4 parameters between every single pair were as the following. D and ADC values of malignant tumors were significantly smaller than those of benign lesions, simple cysts and normal tissues (P = 0.000, respectively). The f value of malignant tumors was significantly higher than that of benign lesions, simple cysts and normal breast tissues (P = 0.001, P = 0.000, and P = 0.000). D and ADC values demonstrated higher sensitivity and specificity in differentiating benign lesions and malignant tumors, with area under the curve (AUC) of 0.952 and 0.945, respectively, while f and D* with the lower AUC of 0.723 and 0.630, respectively. Combining f and D values had a sensitivity up to 98.75%.
DWI response curves in malignant tumors, benign lesions and normal fibroglandular tissues are found to be biexponential fit in comparison with the monoexponential fit for simple cysts. IVIM provides separate quantitative measurement of D for cellularity and f and D* for vascularity and is helpful for differentiation between benign and malignant breast lesions.
利用双指数分析多 b 值扩散加权成像（DWI）获得体素内不相干运动（IVIM）成像中的灌注和弥散信息，并比较这些参数与单指数分析获得的表观扩散系数（ADC）在鉴别良性病变和恶性肿瘤方面的能力。
本前瞻性研究获得了所有患者的知情同意。在 1.5T 上利用对比增强磁共振成像（MRI）和 DWI 对 84 例患者的 40 例恶性肿瘤、41 例良性病变、30 例单纯囊肿和 39 例正常乳腺组织进行成像，共使用 12 个 b 值（范围：0-1000s/mm2）。利用分段双指数分析计算组织弥散度（D）、灌注分数（f）和假性弥散系数（D*）。利用 DWI 数据的单指数拟合计算 ADC（b=0 和 1000s/mm2）。获得正常乳腺组织、单纯囊肿、良性病变和恶性肿瘤的 D、f、D*和 ADC 值。对所有 DWI 参数进行受试者工作特征分析。
两位观察者之间的测量值具有良好的观察者间一致性。恶性肿瘤、良性病变、单纯囊肿和正常乳腺组织之间的 D 值存在显著差异（P=0.000），f、D和 ADC 值也是如此。对这 4 个参数的进一步两两比较结果如下。恶性肿瘤的 D 和 ADC 值明显小于良性病变、单纯囊肿和正常组织（P=0.000）。恶性肿瘤的 f 值明显高于良性病变、单纯囊肿和正常乳腺组织（P=0.001、P=0.000 和 P=0.000）。D 和 ADC 值在鉴别良性病变和恶性肿瘤方面具有更高的敏感性和特异性，曲线下面积（AUC）分别为 0.952 和 0.945，而 f 和 D的 AUC 较低，分别为 0.723 和 0.630。f 和 D 值的组合敏感性高达 98.75%。
与单纯囊肿的单指数拟合相比，恶性肿瘤、良性病变和正常纤维腺体组织的 DWI 反应曲线呈双指数拟合。IVIM 提供了对细胞密度的 D 的单独定量测量和对血管生成的 f 和 D*的定量测量，有助于鉴别良性和恶性乳腺病变。
