Department of Radiology, Carl E. Ravin Advanced Imaging Laboratories, Duke University, Durham, North Carolina 27705, USA.
Med Phys. 2010 Jun;37(6):2627-37. doi: 10.1118/1.3429025.
This work investigates a framework for modeling volumetric breast imaging to compare detection and estimation task performance and optimize quantitative breast imaging.
Volumetric reconstructions of a breast phantom, which incorporated electronic, quantum, and anatomical noise with embedded spherical lesions, were simulated over a range of acquisition angles varying from 4 degrees to 204 degrees with a constant total acquisition dose of 1.5 mGy. A maximum likelihood estimator was derived in terms of the noise power spectrum, which yielded figures of merit for quantitative imaging performance in terms of accuracy and precision. These metrics were computed for estimation of lesion area, volume, and location. Estimation task performance was optimized as a function of acquisition angle and compared to the performance of a more conventional lesion detection task.
Results revealed tradeoffs between electronic, quantum, and anatomical noise. The detection of a 4 mm sphere was optimal at an acquisition angle of 84 degrees, where reconstructed images using a smaller acquisition angle exhibited increased anatomical noise and reconstructed images using a larger acquisition angle exhibited increased quantum and electronic noise. For all estimation tasks, accuracy was found to be fairly constant as a function acquisition angle indicating adequate system calibration, whereas a more significant dependence on acquisition angle was observed for precision performance. Precision for the 2D area estimation task was optimal at approximately 104 degrees, while precision of the 3D volume estimation task was optimal at larger angles (approximately 124 degrees). Precision for the localization task showed orientation dependence where localization was significantly inferior in the depth direction. Overall, precision for localization was optimal at larger angles (i.e., > 125 degrees) compared to the size estimation tasks. Results suggested that for quantitative imaging tasks, the acquisition angle should be larger than currently used in conventional breast tomosynthesis for lesion detection.
Analysis of quantitative imaging performance using Fourier-based metrics highlights the difference between estimation and detection task in volumetric breast imaging and provides a meaningful framework for optimizing the performance of breast imaging systems for quantitative imaging applications.
本研究旨在构建一种容积乳腺成像模型，以比较检测和估计任务的性能，并优化定量乳腺成像。
在总剂量为 1.5 mGy 的情况下，对一个乳腺体模进行了容积重建，该体模结合了电子、量子和解剖噪声，并嵌入了球形病变。模拟了从 4 度到 204 度的一系列采集角度，采用最大似然估计器，根据噪声功率谱推导出了定量成像性能的优劣标准，以评估病变面积、体积和位置的估计准确性和精度。这些指标是针对病变面积、体积和位置的估计任务计算的。作为采集角度的函数，优化了估计任务的性能，并将其与更传统的病变检测任务的性能进行了比较。
结果揭示了电子、量子和解剖噪声之间的权衡。4mm 球体的检测效果在采集角度为 84 度时最佳，较小采集角度的重建图像显示出增加的解剖噪声，较大采集角度的重建图像则显示出增加的量子和电子噪声。对于所有的估计任务，随着采集角度的增加，准确性相当稳定，表明系统校准良好，而精度性能则对采集角度的依赖性更大。2D 面积估计任务的精度在大约 104 度时最佳，而 3D 体积估计任务的精度在更大的角度（约 124 度）时最佳。定位任务的精度表现出方向依赖性，在深度方向上定位明显较差。总的来说，与尺寸估计任务相比，定位任务的精度在更大的角度（即 >125 度）时最佳。结果表明，对于定量成像任务，采集角度应大于传统乳腺断层合成术用于检测病变的角度。
基于傅里叶的定量成像性能分析突出了容积乳腺成像中检测和估计任务之间的差异，并为优化定量乳腺成像应用的乳腺成像系统性能提供了有意义的框架。
