From the Department of Radiology, University of Michigan Medical Center, 1500 E Medical Center Dr, Ann Arbor, MI 48109-5842 (H.P.C., M.M.G., M.A.H., M.N., C.P., M.A.R., A.V.N., C.H.N., P.C., Y.L., L.H., J.W.); and GE Global Research, Niskayuna, NY (S.Z., A.S.).
Radiology. 2014 Dec;273(3):675-85. doi: 10.1148/radiol.14132722. Epub 2014 Jul 7.
To investigate the dependence of microcalcification cluster detectability on tomographic scan angle, angular increment, and number of projection views acquired at digital breast tomosynthesis ( DBT digital breast tomosynthesis ).
A prototype DBT digital breast tomosynthesis system operated in step-and-shoot mode was used to image breast phantoms. Four 5-cm-thick phantoms embedded with 81 simulated microcalcification clusters of three speck sizes (subtle, medium, and obvious) were imaged by using a rhodium target and rhodium filter with 29 kV, 50 mAs, and seven acquisition protocols. Fixed angular increments were used in four protocols (denoted as scan angle, angular increment, and number of projection views, respectively: 16°, 1°, and 17; 24°, 3°, and nine; 30°, 3°, and 11; and 60°, 3°, and 21), and variable increments were used in three (40°, variable, and 13; 40°, variable, and 15; and 60°, variable, and 21). The reconstructed DBT digital breast tomosynthesis images were interpreted by six radiologists who located the microcalcification clusters and rated their conspicuity.
The mean sensitivity for detection of subtle clusters ranged from 80% (22.5 of 28) to 96% (26.8 of 28) for the seven DBT digital breast tomosynthesis protocols; the highest sensitivity was achieved with the 16°, 1°, and 17 protocol (96%), but the difference was significant only for the 60°, 3°, and 21 protocol (80%, P < .002) and did not reach significance for the other five protocols (P = .01-.15). The mean sensitivity for detection of medium and obvious clusters ranged from 97% (28.2 of 29) to 100% (24 of 24), but the differences fell short of significance (P = .08 to >.99). The conspicuity of subtle and medium clusters with the 16°, 1°, and 17 protocol was rated higher than those with other protocols; the differences were significant for subtle clusters with the 24°, 3°, and nine protocol and for medium clusters with 24°, 3°, and nine; 30°, 3°, and 11; 60°, 3° and 21; and 60°, variable, and 21 protocols (P < .002).
With imaging that did not include x-ray source motion or patient motion during acquisition of the projection views, narrow-angle DBT digital breast tomosynthesis provided higher sensitivity and conspicuity than wide-angle DBT digital breast tomosynthesis for subtle microcalcification clusters.
研究微钙化簇检测能力对断层扫描角度、角度增量和数字乳腺断层合成术（DBT）采集的投影视图数量的依赖性。
使用处于步进和拍摄模式的原型 DBT 数字乳腺断层合成系统对乳腺体模进行成像。四个 5cm 厚的体模中嵌入了 81 个模拟微钙化簇，具有三种粒度（细微、中等和明显），使用铑靶和铑滤光片，以 29kV、50mA 和 7 种采集方案进行成像。在四个方案中使用固定的角度增量（分别表示为扫描角度、角度增量和投影视图数量：16°、1°和 17；24°、3°和 9；30°、3°和 11；60°、3°和 21），在三个方案中使用可变增量（40°、可变和 13；40°、可变和 15；和 60°、可变和 21）。六位放射科医生对重建的 DBT 数字乳腺断层合成图像进行了解读，他们定位了微钙化簇并对其显影度进行了评级。
在七种 DBT 数字乳腺断层合成方案中，检测细微簇的平均灵敏度范围为 80%（28 个中的 22.5 个）至 96%（28 个中的 26.8 个）；16°、1°和 17°方案的灵敏度最高（96%），但仅在 60°、3°和 21°方案（80%，P<.002）中差异显著，而在其他五个方案中（P=.01-.15）则未达到显著水平。检测中等和明显大小的簇的平均灵敏度范围为 97%（29 个中的 28.2 个）至 100%（24 个中的 24 个），但差异无统计学意义（P=.08 至>.99）。16°、1°和 17°方案中细微和中等簇的显影度评分高于其他方案；24°、3°和 9°方案中细微簇和 24°、3°和 9°方案中中等簇的差异具有统计学意义；30°、3°和 11°；60°、3°和 21°；和 60°、变量和 21°方案（P<.002）。
在不包括 X 射线源运动或采集投影视图期间患者运动的情况下，窄角 DBT 数字乳腺断层合成术为细微微钙化簇提供了比广角 DBT 数字乳腺断层合成术更高的灵敏度和显影度。
