利用水脂分解 MRI 实现无电离辐射的可重复自动化乳腺密度测量。
Reproducible automated breast density measure with no ionizing radiation using fat-water decomposition MRI.
机构信息
Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York, USA.
Department of Hematology and Oncology, Stony Brook Medicine, Stony Brook, New York, USA.
出版信息
J Magn Reson Imaging. 2018 Oct;48(4):971-981. doi: 10.1002/jmri.26041. Epub 2018 Apr 6.
BACKGROUND
Increased breast density is a significant independent risk factor for breast cancer, and recent studies show that this risk is modifiable. Hence, breast density measures sensitive to small changes are desired.
PURPOSE
Utilizing fat-water decomposition MRI, we propose an automated, reproducible breast density measurement, which is nonionizing and directly comparable to mammographic density (MD).
STUDY TYPE
Retrospective study.
POPULATION
The study included two sample sets of breast cancer patients enrolled in a clinical trial, for concordance analysis with MD (40 patients) and reproducibility analysis (10 patients).
FIELD STRENGTH/SEQUENCE: The majority of MRI scans (59 scans) were performed with a 1.5T GE Signa scanner using radial IDEAL-GRASE sequence, while the remaining (seven scans) were performed with a 3T Siemens Skyra using 3D Cartesian 6-echo GRE sequence with a similar fat-water separation technique.
ASSESSMENT
After automated breast segmentation, breast density was calculated using FraGW, a new measure developed to reliably reflect the amount of fibroglandular tissue and total water content in the entire breast. Based on its concordance with MD, FraGW was calibrated to MR-based breast density (MRD) to be comparable to MD. A previous breast density measurement, Fra80-the ratio of breast voxels with <80% fat fraction-was also calculated for comparison with FraGW.
STATISTICAL TESTS
Pearson correlation was performed between MD (reference standard) and FraGW (and Fra80). Test-retest reproducibility of MRD was evaluated using the difference between test-retest measures (Δ ) and intraclass correlation coefficient (ICC).
RESULTS
Both FraGW and Fra80 were strongly correlated with MD (Pearson ρ: 0.96 vs. 0.90, both P < 0.0001). MRD converted from FraGW showed higher test-retest reproducibility (Δ variation: 1.1% ± 1.2%; ICC: 0.99) compared to MD itself (literature intrareader ICC ≤0.96) and Fra80.
DATA CONCLUSION
The proposed MRD is directly comparable with MD and highly reproducible, which enables the early detection of small breast density changes and treatment response.
LEVEL OF EVIDENCE
3 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;48:971-981.
背景
乳腺密度增加是乳腺癌的一个重要独立危险因素，最近的研究表明，这种风险是可以改变的。因此，需要一种对微小变化敏感的乳腺密度测量方法。
目的
利用水脂分解 MRI，我们提出了一种自动化、可重复的乳腺密度测量方法，该方法是非电离的，并且可以直接与乳腺 X 线摄影密度（MD）相比较。
研究类型
回顾性研究。
人群
本研究包括两组入组临床试验的乳腺癌患者，用于与 MD（40 例）和可重复性分析（10 例）进行一致性分析。
磁场强度/序列：大多数 MRI 扫描（59 次扫描）是在 1.5T GE Signa 扫描仪上使用径向 IDEAL-GRASE 序列进行的，而其余（7 次扫描）是在 3T Siemens Skyra 上使用类似的水脂分离技术的 3D 笛卡尔 6 回波 GRE 序列进行的。
评估
在自动乳腺分割后，使用新开发的测量方法 FraGW 计算乳腺密度，该方法可可靠地反映整个乳腺中的纤维腺体组织和总含水量。基于与 MD 的一致性，FraGW 被校准为基于 MRI 的乳腺密度（MRD），以与 MD 相比较。还计算了之前的乳腺密度测量方法 Fra80（乳腺体素中脂肪分数小于 80%的比例），以与 FraGW 进行比较。
统计学检验
对 MD（参考标准）和 FraGW（和 Fra80）进行 Pearson 相关性分析。使用测试-复测测量值之间的差异（Δ）和组内相关系数（ICC）评估 MRD 的测试-复测可重复性。
结果
FraGW 和 Fra80 与 MD 均呈强相关性（Pearson ρ：0.96 对 0.90，均 P<0.0001）。从 FraGW 转换而来的 MRD 具有更高的测试-复测可重复性（Δ 变化：1.1%±1.2%；ICC：0.99），与 MD 本身（文献中读者内 ICC≤0.96）和 Fra80 相比。
数据结论
所提出的 MRD 与 MD 直接可比，且具有高度可重复性，这使得能够早期检测到微小的乳腺密度变化和治疗反应。
证据水平
3 级 技术功效：1 期 J. Magn. Reson. Imaging 2018；48：971-981.
Zotero 插件