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MRI是诊断乳腺肿瘤的重要方法,其价值已得到公认[1]。常规MRI诊断乳腺肿瘤有较高的灵敏度,但缺乏特异性,月经周期、激素治疗、增生性病变等因素均可能导致假阳性的发生,导致部分病例在传统MRI成像上难以定性[2-4]。弥散加权成像(diffusion-weighted imaging,DWI)可以反映组织的生物学特征,对鉴别乳腺肿瘤性质具有较高的灵敏度和特异度[5-6]。DWI通常在注射钆对比剂前采集,鲜有给药后进行的报道,本研究旨在探讨1.5 T MRI中乳腺肿瘤患者使用钆对比剂是否对DWI有显著性影响,并分析增强前后表观弥散系数(apparent diffusion coefficient,ADC)及指数表观弥散系数(exponent apparent diffusion coefficient,eADC)值的变化情况及其在乳腺良恶性病变鉴别中的价值。
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表 1为b=0及800时增强前后正常乳腺腺体弥散图像SNR、乳腺病灶弥散图像SNR及CNR。配对t检验结果表明正常乳腺腺体及乳腺病灶弥散图像SNR及CNR在注射钆剂前后差异无统计学意义。
时间点 正常乳腺腺体SNR 乳腺病灶SNR CNR b=0 b=800 b=0 b=800 b=0 b=800 增强前 34.75±3.93 22.71±3.14 53.30±5.26 32.47±4.64 18.55±4.84 9.76±4.04 增强后 35.13±4.00 23.12±3.19 53.97±5.53 32.88±5.41 18.84±5.39 9.76±5.35 t值 0.657 1.360 1.534 0.913 0.480 -0.002 P值 0.515 0.181 0.132 0.366 0.633 0.998 注:表中,SNR:信噪比;CNR:对比噪声比。 表 1 正常乳腺腺体和乳腺病灶MRI弥散加权成像图像增强前后SNR及CNR比较(x±s,n=44)
Table 1. SNR and CNR of the normal breast and the lesions before and after contrast enhancement(x±s, n=44)
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增强前后病灶ADC值及eADC值见表 2。乳腺癌增强后ADC值较增强前降低(图 1),平均降幅10.3%;增强后eADC值明显升高,平均升幅11.3%;配对t检验结果显示两者增强前后差异均有统计学意义。良性肿瘤增强后的ADC值平均降低1.9%;增强后的eADC值平均升高2.0%;配对t检验结果显示两者差异无统计学意义。
图 1 乳腺浸润性导管癌患者磁共振图像和组织病理图。
Figure 1. MRI images and pathological image of patient with invasive ductal carcinoma of breast
时间点 乳腺癌(n=21) 乳腺良性肿瘤(n=23) ADC值 eADC值 ADC值 eADC值 增强前 1.11±0.25 0.40±0.09 1.47±0.27 0.30±0.07 增强后 0.99±0.26 0.44±0.10 1.43±0.24 0.31±0.06 t值 -4.023 4.082 -1.700 1.341 P值 0.001 0.001 0.103 0.194 注:表中,ADC:表观弥散系数;eADC:指数表观弥散系数。 表 2 40例乳腺肿瘤患者MRI弥散加权成像图像增强前后ADC值及eADC值比较(x±s)
Table 2. ADC and eADC value of 40 patients with breast tumors before and after contrast enhancement(x±s)
注射钆剂后弥散加权成像对乳腺肿瘤诊断的影响
Evaluation of the diffusion-weighted imaging after contrast for the characterization of breast tumors
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摘要: 目的评估1.5 T MRI中乳腺肿瘤患者使用钆对比剂是否对弥散加权成像(DWI)有显著性影响。方法行乳腺MRI检查的女性患者40例(共计44个病灶),分别测量增强前后DWI图像信噪比(SNR)和对比噪声比(CNR)、病灶增强前后的表观扩散系数(ADC)及指数表观扩散系数(eADC)。结果给药前后DWI图像的SNR及CNR差异无统计学意义。乳腺癌给药前后的ADC值(t=-4.023, P=0.001)及eADC值(t=4.082, P=0.001)差异有统计学意义,良性肿瘤给药前后的ADC值(t=-1.700, P=0.103)及eADC值(t=1.341, P=0.194)差异无统计学意义。结论增强后行DWI是可行的,并且有助于提高其鉴别乳腺良恶性肿瘤的能力。Abstract: Objective To evaluate the effects of intravenous gadolinium-DTPA on the diffusion-weighted imaging(DWI) of the breast. Methods A total of 40 women with 44 mass-like breast lesions were examined using 1.5-T MRI. The signal-to-noise ratios(SNRs) of the normal breast and the lesions, the contrast-to-noise ratios(CNRs), apparent diffusion coefficient(ADC), and exponent apparent diffusion coefficient(eADC) values of each lesion were measured from the DWI images before and after contrast enhancement. Results The SNRs and CNRs of the DWI images before and after contrast enhancement were not significantly different. In addition, no significant difference between the ADC and eADC values before and after contrast enhancement was observed in the benign lesions, whereas the opposite was observed in the malignant lesions. Conclusions The application of DWI after contrast enhancement is feasible in characterizing lesions in the breast. After contrast enhancement, the ADC values were significantly lower, and the eADC values were significantly higher in breast carcinomas. DWI after contrast media may improve the diagnosis of malignant breast lesions.
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Key words:
- Breast neoplasms /
- magnetic resonance imaging /
- Diffusion /
- Gadolinium DTPA
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表 1 正常乳腺腺体和乳腺病灶MRI弥散加权成像图像增强前后SNR及CNR比较(x±s,n=44)
Table 1. SNR and CNR of the normal breast and the lesions before and after contrast enhancement(x±s, n=44)
时间点 正常乳腺腺体SNR 乳腺病灶SNR CNR b=0 b=800 b=0 b=800 b=0 b=800 增强前 34.75±3.93 22.71±3.14 53.30±5.26 32.47±4.64 18.55±4.84 9.76±4.04 增强后 35.13±4.00 23.12±3.19 53.97±5.53 32.88±5.41 18.84±5.39 9.76±5.35 t值 0.657 1.360 1.534 0.913 0.480 -0.002 P值 0.515 0.181 0.132 0.366 0.633 0.998 注:表中,SNR:信噪比;CNR:对比噪声比。 表 2 40例乳腺肿瘤患者MRI弥散加权成像图像增强前后ADC值及eADC值比较(x±s)
Table 2. ADC and eADC value of 40 patients with breast tumors before and after contrast enhancement(x±s)
时间点 乳腺癌(n=21) 乳腺良性肿瘤(n=23) ADC值 eADC值 ADC值 eADC值 增强前 1.11±0.25 0.40±0.09 1.47±0.27 0.30±0.07 增强后 0.99±0.26 0.44±0.10 1.43±0.24 0.31±0.06 t值 -4.023 4.082 -1.700 1.341 P值 0.001 0.001 0.103 0.194 注:表中,ADC:表观弥散系数;eADC:指数表观弥散系数。 -
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