Boone J, Chen L, Nosratieh A, Abbey C, Lindfors K, Aminololama-Shakeri S, Seibert J
UC Davis Medical Center, Sacramento, CA.
University of California, Davis, Sacramento, California.
Med Phys. 2012 Jun;39(6Part24):3914. doi: 10.1118/1.4735975.
The role of breast density in cancer detection has been well characterized, and newer modalities such as breast tomosynthesis and breast CT (bCT) were developed to improve cancer detection in the dense breast by reducing anatomical complexity. Anatomical noise was characterized on a small cohort of patient images and compared across digital mammography, tomosynthesis, and bCT images.
An IRB-approved and HIPPA-compliant clinical study was performed on women undergoing breast biopsy, and mammography, tomosynthesis, and bCT were performed on both breasts immediately prior to biopsy. A total of 23 women participated in this study, and the unaffected breast (no lesion) was evaluated. A total of 1000 regions of interest were sampled on each image data set, and the 2D noise power spectrum (NPS) was evaluated. This was radially averaged to produce a 1D NPS, and the NPS was fit to a power law: ln{NPS(f)} = alpha+betaxln(f), over an anatomically-relevant range of spatial frequencies. The slope, beta, was averaged across patients and compared between modalities and projections.
The value of beta was determined for bCT data sets, and they were 1.75 (0.424), 1.83 (0.352), and 1.79 (0.397), for the coronal, sagittal and axial views, respectively. For tomosynthesis, beta was 3.06 (0.361) and 3.10 (0.315) for the CC and MLO views, respectively. For mammography, these values were 3.17 (0.226) and 3.30 (0.236), for the CC and MLO views, respectively. The values of beta for breast CT were significantly different than those for tomosynthesis and mammography (p<0.001, all 12 comparisons).
The results of this investigation demonstrate that the anatomical complexity of the breast, as characterized by the parameter beta, is statistically similar between mammography and tomosynthesis, a somewhat surprising finding. The breast CT image data, however, demonstrate a statistically-significant reduction in beta across all projections. Funded in part by Hologic Corporation and by a grant from the National Institute of Biomedical Imaging and Bioengineering, EB002138.
乳腺密度在癌症检测中的作用已得到充分表征，为通过降低解剖结构复杂性来提高致密型乳腺中的癌症检测率，开发了乳腺断层合成成像和乳腺CT（bCT）等更新的成像方式。对一小群患者图像的解剖噪声进行了表征，并在数字乳腺X线摄影、断层合成成像和bCT图像之间进行了比较。
对接受乳腺活检的女性进行了一项经机构审查委员会批准且符合健康保险流通与责任法案的临床研究，在活检前立即对双侧乳房进行乳腺X线摄影、断层合成成像和bCT检查。共有23名女性参与了本研究，并对未受影响的乳房（无病变）进行了评估。在每个图像数据集上共采样1000个感兴趣区域，并评估二维噪声功率谱（NPS）。将其进行径向平均以生成一维NPS，并在与解剖结构相关的空间频率范围内将NPS拟合为幂律：ln{NPS(f)} = α + β×ln(f)。斜率β在患者之间进行平均，并在不同成像方式和投照之间进行比较。
确定了bCT数据集的β值，冠状面、矢状面和横断面视图的β值分别为1.75（0.424）、1.83（0.352）和1.79（0.397）。对于断层合成成像，CC位和MLO位视图的β值分别为3.06（0.361）和3.10（0.315）。对于乳腺X线摄影，CC位和MLO位视图的这些值分别为3.17（0.226）和3.30（0.236）。乳腺CT的β值与断层合成成像和乳腺X线摄影的β值显著不同（所有12项比较，p<0.001）。
本研究结果表明，以β参数表征的乳腺解剖结构复杂性在乳腺X线摄影和断层合成成像之间在统计学上相似，这是一个有点令人惊讶的发现。然而，乳腺CT图像数据在所有投照中均显示β值在统计学上显著降低。部分由Hologic公司以及美国国立生物医学成像和生物工程研究所的EB002138资助。
