Maximizing Iodine Contrast-to-Noise Ratios in Abdominal CT Imaging through Use of Energy Domain Noise Reduction and Virtual Monoenergetic Dual-Energy CT.
Maximizing Iodine Contrast-to-Noise Ratios in Abdominal CT Imaging through Use of Energy Domain Noise Reduction and Virtual Monoenergetic Dual-Energy CT.
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DOI：
10.1148/radiol.2015140857
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发表时间：
2015-08
期刊：
影响因子：
19.7
通讯作者：
McCollough CH
中科院分区：
文献类型：
--
作者：
Leng S;Yu L;Fletcher JG;McCollough CH
确定使用能量域降噪和虚拟单能双能（DE）CT图像时腹部计算机断层扫描（CT）的碘对比噪声比（CNR），并将CNR与80、100、120和140 kV下单能CT获得的CNR进行比较。该符合HIPAA的研究获得了机构审查委员会的批准，豁免了知情同意。将装有稀释碘造影剂的注射器放入30 cm、35 cm和45 cm宽的水模型中，并用双源CT扫描仪在DE和单能量模式下进行扫描，扫描仪输出匹配。生成虚拟单能图像，能量范围为40至110 keV，步进10 keV。应用先前开发的能量域降噪算法，通过利用能量域中的信息冗余来降低图像噪声。计算图像噪声和碘CNR。为了显示该技术的潜在临床受益，将其回顾性应用于一名59岁男性患者的肝脏临床DE CT研究，该研究使用传统和迭代重建技术。通过配对t检验，比较了在每个虚拟单能能量（单位：千电子伏）和体模尺寸下，有和没有能量域降噪的虚拟单能图像的图像噪声和CNR。还将虚拟单能量图像的CNR与用80、100、120和140 kV采集的单能量图像的CNR进行了比较。通过使用能量域降噪技术，DE虚拟单能图像的降噪率高达59%（28.7/65.7）。对于商业虚拟单能图像，最大碘CNR在70 keV时达到，对于30、35和45 cm体模分别为18.6、16.6和10.8。能量域噪声降低后，在40 keV时达到最大碘CNR，并增加到30.6、25.4和16.5。这些CNR表示使用能量域降噪技术的改善高达64%（12.0/18.6）。对于最佳管电位下的单能量CT，碘CNR为29.1（80 kV）、21.2（80 kV）和11.5（100 kV）。对于患者图像，与标准滤波反投影图像相比，使用能量域降噪技术观察到39%（24/61）的降噪和67%（0.74/1.10）的CNR改善。通过能量域降噪和虚拟单能DE CT，可使成人腹部CT的碘CNR最大化。
To determine the iodine contrast-to-noise ratio (CNR) for abdominal computed tomography (CT) when using energy domain noise reduction and virtual monoenergetic dual-energy (DE) CT images and to compare the CNR to that attained with single-energy CT at 80, 100, 120, and 140 kV. This HIPAA-compliant study was approved by the institutional review board with waiver of informed consent. A syringe filled with diluted iodine contrast material was placed into 30-, 35-, and 45-cm-wide water phantoms and scanned with a dual-source CT scanner in both DE and single-energy modes with matched scanner output. Virtual monoenergetic images were generated, with energies ranging from 40 to 110 keV in 10-keV steps. A previously developed energy domain noise reduction algorithm was applied to reduce image noise by exploiting information redundancies in the energy domain. Image noise and iodine CNR were calculated. To show the potential clinical benefit of this technique, it was retrospectively applied to a clinical DE CT study of the liver in a 59-year-old male patient by using conventional and iterative reconstruction techniques. Image noise and CNR were compared for virtual monoenergetic images with and without energy domain noise reduction at each virtual monoenergetic energy (in kiloelectron volts) and phantom size by using a paired t test. CNR of virtual monoenergetic images was also compared with that of single-energy images acquired with 80, 100, 120, and 140 kV. Noise reduction of up to 59% (28.7/65.7) was achieved for DE virtual monoenergetic images by using an energy domain noise reduction technique. For the commercial virtual monoenergetic images, the maximum iodine CNR was achieved at 70 keV and was 18.6, 16.6, and 10.8 for the 30-, 35-, and 45-cm phantoms. After energy domain noise reduction, maximum iodine CNR was achieved at 40 keV and increased to 30.6, 25.4, and 16.5. These CNRs represented improvement of up to 64% (12.0/18.6) with the energy domain noise reduction technique. For single-energy CT at the optimal tube potential, iodine CNR was 29.1 (80 kV), 21.2 (80 kV), and 11.5 (100 kV). For patient images, 39% (24/61) noise reduction and 67% (0.74/1.10) CNR improvement were observed with the energy domain noise reduction technique when compared with standard filtered back-projection images. Iodine CNR for adult abdominal CT may be maximized with energy domain noise reduction and virtual monoenergetic DE CT.