From the Department of Radiology (A.M., R.C.N., T.A.J., E.K.P., A.B., D.M.) and Carl E. Ravin Advanced Imaging Laboratories (E.S., K.R.C., J.M.W.), Duke University Medical Center, Box 3808 Erwin Rd, Durham, NC 27710.
Radiology. 2014 Sep;272(3):767-76. doi: 10.1148/radiol.14132856. Epub 2014 May 15.
To investigate whether dual-energy multi-detector row computed tomography (CT) with virtual monochromatic imaging can overcome renal cyst pseudoenhancement in a phantom experiment and a clinical study.
This retrospective single-center HIPAA-compliant study was approved by the institutional review board, with waiver of informed consent. Four renal compartments inserted into torso phantoms were filled with saline to simulate the unenhanced state and with iodinated solutions to simulate the three levels of renal parenchyma enhancement (140, 180, and 240 HU). Saline-filled spheres simulating renal cysts (15 and 18 mm in diameter) were serially suspended in the renal compartments and imaged with dual-energy and single-energy multi-detector row CT at four different energy levels (80, 100, 120, and 140 kVp). In addition, 28 patients (mean age, 66 years ± 10; mean body mass index, 31.3 kg/m(2) ± 6.2) with 34 intrarenal cysts were included. Virtual monochromatic images were reconstructed in 10-keV increments at energy levels ranging from 40 to 140 keV. Phantom and clinical data were analyzed by using multivariate regression analysis.
In the phantom experiment, all polychromatic image data sets showed pseudoenhancement (postcontrast attenuation increase >10 HU) in all investigated conditions, with a significant effect on cyst size (P <.001), location (P <.001), and renal background attenuation level (P <.001). Virtual monochromatic images at energy levels ranging from 80 to 140 keV did not show pseudoenhancement, with the minimum attenuation increase (mean, 6.1 HU ± 1.6; range, 1.6-7.7 HU) on 80-keV images. In patients, pseudoenhancement never occurred on virtual monochromatic images at energy levels ranging from 90 to 140 keV. Patient body size had a significant effect (P = .007) on selection of the optimal monochromatic energy level.
Dual-energy multi-detector row CT with reconstruction of virtual monochromatic images at an optimal energy level can overcome renal cyst pseudoenhancement.
在一项体模实验和临床研究中，探讨双能多排 CT 虚拟单能量成像是否能克服肾囊肿的假性增强。
本回顾性单中心 HIPAA 合规研究获得了机构审查委员会的批准，并豁免了知情同意。将四个插入体模躯干的肾腔用盐水填充以模拟未增强状态，并用含碘溶液模拟三种肾实质增强水平（140、180 和 240HU）。用盐水填充的模拟肾囊肿（直径 15 和 18mm）的球体被连续悬挂在肾腔内，并用双能和单能多排 CT 在四个不同的能量水平（80、100、120 和 140kVp）进行扫描。此外，还纳入了 28 例（平均年龄 66 岁±10 岁；平均体重指数 31.3kg/m2±6.2）患者共 34 个肾内囊肿。在 40-140keV 的能量水平上，以 10keV 为增量重建虚拟单能量图像。通过多元回归分析对体模和临床数据进行分析。
在体模实验中，所有多光谱图像数据集在所有研究条件下均显示假性增强（增强后衰减增加>10HU），且与囊肿大小（P<.001）、位置（P<.001）和肾背景衰减水平（P<.001）有显著关系。在 80-140keV 的能量水平上，虚拟单能量图像没有显示假性增强，80keV 图像的衰减增加最小（平均值 6.1HU±1.6；范围 1.6-7.7HU）。在患者中，90-140keV 的虚拟单能量图像从未出现过假性增强。患者体型对最佳单能量水平的选择有显著影响（P=.007）。
双能多排 CT 重建虚拟单能量图像可在最佳能量水平上克服肾囊肿的假性增强。
