Barufaldi Bruno, Vent Trevor L, Acciavatti Raymond J, Bakic Predrag R, Noël Peter B, Conant Emily F, Maidment Andrew D A
Department of Radiology, University of Pennsylvania, Philadelphia, United States.
Proc SPIE Int Soc Opt Eng. 2020 Feb;11312. doi: 10.1117/12.2549600. Epub 2020 Mar 16.
The limited angle and limited number of projections in digital breast tomosynthesis (DBT) produce under-sampled datasets that may compromise calcification detection. Small breast lesions, such as microcalcifications, may not be discernible without sufficient sampling in the reconstructed DBT images. We propose a virtual clinical trial (VCT) method to evaluate the calcification detection in DBT using computer simulations of breast phantoms, images, and virtual readers. We used multiple-reader multiple-case (MRMC) receiver operating characteristic (ROC) analyses to evaluate the performance of channelized Hotelling observers (CHOs) in calcification detection. The angular motion path of the x-ray source was varied to simulate different DBT acquisition geometries. We simulated continuous and step-and-shoot x-ray source motion and three angular motion paths: ±7.5°, ±15°, and ±25°. The detection of calcifications is affected by the angular motion path, particularly for the ±25° angular range, combined with continuous tube motion, larger detector element sizes (0.14 mm) and larger reconstructed voxel sizes (0.10 mm). When an angular range of ±25° is compared to ±7.5°, the difference in the area under the curve (AUC) is -0.030 (' ratio=0.633) and -0.067 (' ratio=0.584), for one- and two-voxel calcifications (0.1 mm and 0.2 mm), respectively. There is no significant difference in calcification detection using images acquired with ±7.5° and ±15°. The results provide insight on the impact of angular range for calcification detection, an ongoing limitation of tomosynthesis.
数字乳腺断层合成（DBT）中有限的投影角度和数量会产生欠采样数据集，这可能会影响钙化检测。如果在重建的DBT图像中没有足够的采样，微小的乳腺病变，如微钙化，可能无法被识别。我们提出了一种虚拟临床试验（VCT）方法，通过乳腺体模、图像和虚拟阅片者的计算机模拟来评估DBT中的钙化检测。我们使用多阅片者多病例（MRMC）接收器操作特性（ROC）分析来评估通道化霍特林观察者（CHO）在钙化检测中的性能。改变X射线源的角运动路径以模拟不同的DBT采集几何形状。我们模拟了连续和步进式X射线源运动以及三种角运动路径：±7.5°、±15°和±25°。钙化的检测受角运动路径的影响，特别是对于±25°的角范围，再结合连续的管运动、更大的探测器元件尺寸（0.14毫米）和更大的重建体素尺寸（0.10毫米）。当将±25°的角范围与±7.5°进行比较时，对于单像素和双像素钙化（0.1毫米和0.2毫米），曲线下面积（AUC）的差异分别为-0.030（'比率=0.633）和-0.067（'比率=0.584）。使用±7.5°和±15°采集的图像进行钙化检测没有显著差异。这些结果为角范围对钙化检测的影响提供了见解，而角范围是断层合成目前存在的一个限制。
