Fuchs Tobias A, Stehli Julia, Dougoud Svetlana, Sah Bert-Ram, Bull Sacha, Clerc Olivier F, Possner Mathias, Buechel Ronny R, Gaemperli Oliver, Kaufmann Philipp A
Cardiac Imaging, Nuclear Medicine, University Hospital Zurich, Ramistrasse 100, NUK C 42, 8091, Zurich, Switzerland.
Int J Cardiovasc Imaging. 2014 Oct;30(7):1399-405. doi: 10.1007/s10554-014-0474-0. Epub 2014 Jul 4.
To explore the feasibility of coronary artery calcium (CAC) measurement from low-dose contrast enhanced coronary CT angiography (CCTA) as this may obviate the need for an unenhanced CT scan. 52 patients underwent unenhanced cardiac CT and prospectively ECG triggered contrast enhanced CCTA (Discovery HD 750, GE Healthcare, Milwaukee, WI, USA). The latter was acquired in single-source dual-energy mode [gemstone spectral imaging (GSI)]. Virtual unenhanced images were generated from GSI CCTA by monochromatic image reconstruction of 70 keV allowing selective iodine material suppression. CAC scores from virtual unenhanced CT were compared to standard unenhanced CT including a linear regression model. After iodine subtraction from the contrast enhanced CCTA the attenuation in the ascending aorta decreased significantly from 359 ± 61 to 54 ± 8 HU (P < 0.001), the latter comparing well to the value of 64 ± 55 HU found in the standard unenhanced CT (P = ns) confirming successful iodine subtraction. After introducing linear regression formula the mean values for Agatston, Volume and Mass scores of virtual unenhanced CT were 187 ± 321, 72 ± 114 mm(3), and 27 ± 46 mg/cm(3), comparing well to the values from standard unenhanced CT (187 ± 309, 72 ± 110 mm(3), and 27 ± 45 mg/cm(3)) yielding an excellent correlation (r = 0.96, r = 0.96, r = 0.92; P < 0.001). Mean estimated radiation dose revealed 0.83 ± 0.02 mSv from the unenhanced CT and 1.70 ± 0.53 mSv from the contrast enhanced CCTA. Single-source dual-energy scanning with GSI allows CAC quantification from low dose contrast enhanced CCTA by virtual iodine contrast subtraction.
为探讨从低剂量对比增强冠状动脉CT血管造影（CCTA）测量冠状动脉钙化（CAC）的可行性，因为这可能无需进行非增强CT扫描。52例患者接受了非增强心脏CT检查，并前瞻性地进行了心电图触发的对比增强CCTA（Discovery HD 750，通用电气医疗集团，美国威斯康星州密尔沃基）。后者以单源双能量模式[宝石光谱成像（GSI）]采集。通过70keV的单色图像重建从GSI CCTA生成虚拟非增强图像，从而实现选择性碘物质抑制。将虚拟非增强CT的CAC评分与标准非增强CT进行比较，包括线性回归模型。从对比增强CCTA中减去碘后，升主动脉的衰减从359±61显著降低至54±8HU（P<0.001），后者与标准非增强CT中发现的64±55HU的值相当（P=无显著性差异），证实碘减法成功。引入线性回归公式后，虚拟非增强CT的阿加斯顿、体积和质量评分的平均值分别为187±321、72±114mm³和27±46mg/cm³，与标准非增强CT的值（187±309、72±110mm³和27±45mg/cm³）相当，相关性极佳（r=0.96、r=0.96、r=0.92；P<0.001）。平均估计辐射剂量显示，非增强CT为0.83±0.02mSv，对比增强CCTA为1.70±0.53mSv。采用GSI的单源双能量扫描允许通过虚拟碘对比剂减法从低剂量对比增强CCTA中进行CAC定量。
