摘要
目的探讨乳腺动态增强MRI时间分辨率对乳腺良、恶性病变药代动力学定量参数及诊断效能的影响。方法回顾性分析经穿刺活检或手术病理证实的乳腺病变患者，其中良性病灶26个、恶性病灶29个。患者均行动态增强乳腺MRI检查，采用结合并行采集、水脂分离Dixon方法及随机轨迹时间分辨成像技术的容积内插值法屏气检查序列（简称CDT—VIBE序列）。原始序列为时间分辨率12s的动态序列，通过移除采样点的方法分别模拟时间分辨率为24、36、48、60s的动态序列。测量不同时间分辨率乳腺良、恶性病变的定量参数值，包括容量转移常数（Ktrans）、速率常数（Kep）、血管外细胞外间隙容积分数（Ve）和注射对比剂后60s内对比剂浓度．时间曲线下面积（iAUC）。采用重复测量方差分析比较乳腺良、恶性病变不同时间分辨率条件下各定量参数值的差异；以病理结果为金标准，对不同分辨率下各动态参数的诊断效能进行ROE分析，评价各参数的诊断效能。结果随着时间分辨率从12～60S变化，良性病变的K～和K值逐渐升高[Ktrans值为（0．147＋0．084）／min～（0．170＋0．085）／min，k值为（0．321＋0．176）／min～（0．433＋0．175）／mini，恶性病变的Ktrans和Kep值逐渐降低[ktrans值为（0．373＋0．210）／min～（0．259＋0．122）／min，k值为（0．929＋0．402）／min～（0．581±0．143）／min]；良、恶性病变Ve值的变化幅度较小且无明显规律；良、恶性病变的iAUC值呈下降趋势[良性病变为（9．192＋4．660）～（7．388＋3．065），恶性病变为（20．221＋9．876）-（12．850＋5．194）]。不同时间分辨率下，乳腺良、恶性病变的Ktrans、kep、ve和iAUC差异均有统计学意义（P均〈0．05），其中12S、24s与36S间Ktrans值差异有统计学意义（P均〈0．05），12S与其他各时间分辨率间Kep值差异均有统计学意义（P均〈0．01），24S与其他各时间分辨率间Ve值差异均有统计学意义（P均〈0．01），除12S与24S间iAUC值差异无统计学意义外（P=1．000），其余时间分辨率间的iAUC值差异均有统计学意义（P均〈0．05）。Ktrans和Kep在12s动态序列下的曲线下面积最大（分别为0．887、0．939），iAUC在24s动态序列下的曲线下面积最大（0．877），Ve的曲线下面积为0．511～0．601，低于其他参数。结论时间分辨率在24s以上能基本保证药代动力学定量参数计算值相对稳定并具有较好的诊断效能。
Objective To evaluate the effect of temporal resolution of breast dynamic contrast-enhancing （DCE）-MRI on pharmacokinetic parameters and diagnostic performance in benign and malignant breast lesions.Methods Retrospective review was performed on 26 benign and 29 malignant breast lesions which were proven pathologically by surgery or biopsy. Dynamic contrast enhanced breast MRI using a new volume-interpolated-breath-hold examination sequence combining parallel acquisition,Dixon fat separation and time-resolved imaging with interleaved stochastic trajectories （CDT-VIBE） was performed in all patients. The original time resolution of this sequence was 12 s and based on which, dynamic sequences with different temporal resolutions of 24 s, 36 s, 48 s and 60 s were simulated by a sample-removing method and were used for the calculation of pharmacokinetic parameters, including volume transfer constant （Ktrans）, constant flux rate （Kep,）, volume of extravascular extracellular space （Ve） and area under the curve at initial 60 s （iAUC）, to observe their changes with different temporal resolution. The repeated measurement of analysis of variance was used to explore significant changes in pharmacokinetics parameters with different temporal resolution. To evaluate the diagnostic efficiency of parameters with different temporal resolution, ROC analysis was performed in accordance with pathological findings. Results With decrease of temporal resolution from 12 to 60 s, there was a significant increase in Ktrans and Kep, of benign lesions [Ktrans： （0.147 ±0.084）/min to （0.170 ± 0.085）/min, Kep： （0.321 -± 0.176）/min to （0.433± 0.175）/mini and steady decrease in Ktrans and Kep of malignant lesions [Ktrans： （0.373 ±0.210）/rain to （0.259± 0.122）/min, Kep： （0.929± 0.402）/min to （0.581 ± 0.143）/min]; the changes of Vo were less significant and irregular; the values of iAUC decreased both in benign [（9.192 ±4.660） to （7.388± 3.065）] and malignant [（20.221±9.876） to （12.850±5.194）] lesions.The changes in all parameters with different time resolution were statistically significant in benign and malignant lesions （all P〈0.05）. By pair-wise comparison between different time resolution, the changes of Ktrans among 12 s, 24 s and 36 s （all P〈0.05）, the changes of Kep between 12 s and others （all P〈0.01）, the changes of Vo between 24 s and others （all P〈0.01）, and the changes among all pairs of iAUC were significant （all P〈0.05） except for 12 s and 24 s （P=1.000）. The best AUC value of Ktrans and Kep between benign and malignant lesions were achieved with 12 s dynamic sequences （0.887, 0.939）, and the best AUC value of iAUC was with 24 s sequences （0.877）. The AUC values of V. were between 0.511 to 0.601, which was lower than that of other three parameters. Conclusion A 24 s or higher temporal resolution of DCE-MRI should be able to provide consistent differentiation of pharmacokinetic parameters in benign and malignant breast lesions.
出处
《中华放射学杂志》
CAS
CSCD
北大核心
2015年第11期823-827,共5页
Chinese Journal of Radiology
基金
国家自然科学基金（81371525）
山东省科技发展计划（2008GG30002041）
关键词
乳腺肿瘤
磁共振成像
时间分辨率
Breast neoplasm
Magnetic resonance imaging
Temporal resolution
