Eppenberger Patrick, Marcon Magda, Ho Michael, Del Grande Filippo, Frauenfelder Thomas, Andreisek Gustav
From the *Polyclinic Crossline, Medical Services of the City of Zurich; and †Institute for Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Switzerland; and ‡Department of Radiology, Ospedale Regionale di Lugano, Lugano, Switzerland.
J Comput Assist Tomogr. 2016 Jul-Aug;40(4):658-62. doi: 10.1097/RCT.0000000000000413.
The aim of this study was to evaluate the feasibility of applying the high dynamic range (HDR) technique to radiographic imaging to expand the dynamic range of conventional radiographic images using a colored multiexposure approach.
An appropriate study object was repeatedly imaged using a range of different imaging parameters using a standard clinical x-ray unit. An underexposed image (acquired at 80 keV), an intermediate exposed image (110 keV), and an overexposed image (140 keV) were chosen and combined to a 32-bit colored HDR image. To display the resulting HDR image on a regular color display with typically 8 bits per channel, the Reinhard tone mapping algorithm was applied. The source images and the resulting HDR image were qualitatively evaluated by 5 independent radiologists with regard to the visibility of the different anatomic structures using a Likert scale (1, not visible, to 5, excellent visibility). Data were presented descriptively.
High dynamic range postprocessing was possible without malalignment or image distortion. Application of the Reinhardt algorithm did not cause visible artifacts. Overall, postprocessing time was 7 minutes 10 seconds for the whole process. Visibility of anatomic structure was rated between 1 and 5, depending on the anatomic structure of interest. Most authors rated the HDR image best before individual source images.
This experimental trial showed the feasibility of applying the HDR technique to radiographic imaging to expand the dynamic range of conventional radiographic images using a colored multiexposure approach.
本研究的目的是评估将高动态范围（HDR）技术应用于放射成像的可行性，以使用彩色多曝光方法扩展传统放射图像的动态范围。
使用标准临床X射线设备，采用一系列不同的成像参数对合适的研究对象进行重复成像。选择一张曝光不足的图像（在80keV下采集）、一张中等曝光的图像（110keV）和一张过度曝光的图像（140keV），并将它们组合成一张32位彩色HDR图像。为了在通常每个通道8位的普通彩色显示器上显示生成的HDR图像，应用了Reinhard色调映射算法。5名独立的放射科医生使用李克特量表（1表示不可见，5表示可见性极佳）对源图像和生成的HDR图像中不同解剖结构的可见性进行了定性评估。数据以描述性方式呈现。
高动态范围后处理是可行的，不会出现错位或图像失真。应用Reinhardt算法不会产生可见伪影。总体而言，整个过程的后处理时间为7分10秒。解剖结构的可见性根据感兴趣的解剖结构在1至5之间评级。大多数作者将HDR图像的评级高于单个源图像。
该实验表明，使用彩色多曝光方法将HDR技术应用于放射成像以扩展传统放射图像的动态范围是可行的。
