1 Department of Diagnostic Radiology, The University of Texas MD Anderson Cancer Center, Houston, TX.
2 Department of Diagnostic Radiology, UT Southwestern Medical Center, 2201 Inwood Rd, Dallas, TX 75390-8585.
AJR Am J Roentgenol. 2018 Jan;210(1):214-221. doi: 10.2214/AJR.17.18267. Epub 2017 Nov 1.
The purpose of this study was to assess the feasibility of a short protocol for screening breast MRI that is noninferior to standard-of-care (SOC) MRI in image quality that complies with American College of Radiology accreditation requirements.
In a prospective feasibility trial, 23 women at high risk underwent both an initial SOC MRI examination that included axial iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) and T1-weighted volume imaging for breast assessment (VIBRANT) dynamic contrast-enhanced sequences and a separate short breast MRI protocol comprising a fast spin-echo (FSE) triple-echo Dixon T2 sequence for T2-weighted imaging and a 3D dual-echo fast spoiled gradient-echo two-point Dixon sequence for dynamic contrast-enhanced imaging from October 1, 2015, through May 2, 2016. Image quality assessment was performed by three radiologists, who scored the images for fat saturation, artifact severity, and quality of normal anatomic structures. Enhancing lesions were evaluated according to BI-RADS MRI features. Quantitative analysis was performed by measuring the signal intensity of anatomic areas in each patient.
The mean acquisition time for short-protocol breast MRI was 9.42 minutes and for SOC MRI was 22.09 minutes (p < 0.0001). The mean table times were 13.92 and 35.87 minutes (p < 0.0001). Compared with the FSE triple-echo Dixon T2 short-protocol breast MRI sequence, the IDEAL SOC MRI sequence had significantly worse motion artifact (p < 0.01) and fat saturation (p = 0.04). The other parameters did not differ significantly. Quantitative analysis showed that the FSE triple-echo Dixon T2 sequence had more effective fat saturation and higher tissue contrast. All five lesions were given the same assessments by the readers, and at BI-RADS lesion morphologic ranking, identical high image quality scores were assigned to both the VIBRANT and 3D dual-echo fast spoiled gradient-echo 2-point Dixon sequences.
Short-protocol breast MRI comprising a T2-weighted sequence and a fast dynamic sequence with less than 10-minute acquisition time is feasible and has image quality at least equivalent to that of an SOC MRI protocol with a > 20-minute mean acquisition time. Larger studies comparing the cancer detection rate, sensitivity, and specificity of each imaging protocol are needed to determine whether short-protocol breast MRI can replace SOC MRI to screen patients at high breast cancer risk.
本研究旨在评估一种用于乳腺 MRI 筛查的短方案的可行性，该方案在符合美国放射学院认证要求的图像质量方面不劣于标准护理（SOC）MRI。
在一项前瞻性可行性试验中，23 名高危女性同时接受了初始 SOC MRI 检查，该检查包括轴向迭代分解水和脂肪，采用回声不对称和最小二乘法估计（IDEAL）以及 T1 加权容积成像用于乳腺评估（VIBRANT）动态对比增强序列，以及单独的短乳腺 MRI 方案，包括用于 T2 加权成像的快速自旋回波（FSE）三回波 Dixon T2 序列和用于动态对比增强成像的 3D 双回波快速扰相梯度回波两点 Dixon 序列，从 2015 年 10 月 1 日至 2016 年 5 月 2 日。三位放射科医生对图像的脂肪饱和度、伪影严重程度和正常解剖结构的质量进行了评分，对增强病变根据 BI-RADS MRI 特征进行了评估。通过测量每位患者的解剖区域的信号强度进行定量分析。
短方案乳腺 MRI 的平均采集时间为 9.42 分钟，SOC MRI 的平均采集时间为 22.09 分钟（p < 0.0001）。平均台面时间分别为 13.92 分钟和 35.87 分钟（p < 0.0001）。与 FSE 三回波 Dixon T2 短方案乳腺 MRI 序列相比，IDEAL SOC MRI 序列的运动伪影明显更差（p < 0.01），脂肪饱和度也较差（p = 0.04）。其他参数没有显著差异。定量分析显示，FSE 三回波 Dixon T2 序列的脂肪饱和效果更好，组织对比度更高。所有 5 个病变均被读者进行了相同的评估，在 BI-RADS 病变形态学分级中，VIBRANT 和 3D 双回波快速扰相梯度回波两点 Dixon 序列均被赋予相同的高图像质量评分。
包括 T2 加权序列和快速动态序列在内的采集时间少于 10 分钟的短方案乳腺 MRI 是可行的，其图像质量至少与采集时间超过 20 分钟的 SOC MRI 方案相当。需要更大规模的研究来比较每种成像方案的癌症检出率、灵敏度和特异性，以确定短方案乳腺 MRI 是否可以替代 SOC MRI 来筛查高危乳腺癌患者。
