Kashani Hany, Wright Graham, Ursani Ali, Liu Garry, Hashemi Masoud, Paul Narinder S
J Comput Assist Tomogr. 2018 Mar/Apr;42(2):240-247. doi: 10.1097/RCT.0000000000000663.
The study aims to optimize visualization of the coronary wall during computed tomography coronary angiography.
A coronary plaque phantom was scanned on a wide-volume computed tomography scanner. Spatial resolution, contrast resolution, and vessel wall thickness were measured at different x-ray tube currents and voltages.
Spatial resolution ranged from 0.385 to 0.625 mm and was significantly lower at higher currents. Contrast-to-noise ratio was significantly higher at higher currents. The most accurate wall thickness measurements were quantified at 300 and 400 mA for 80 and 100 kVp and 300 mA for 120 and 135 kVp.
Lower spatial resolution at higher currents was due to added blur from increased focal spot size. Contrast-to-noise ratio was higher at higher currents owing to decreased quantum noise. Wall thickness was measured more accurately at intermediate currents with midrange contrast-to-noise ratio but optimal spatial resolution. For accurate coronary wall thickness measurement, contrast-to-noise ratio is compromised to achieve optimal spatial resolution.
本研究旨在优化计算机断层扫描冠状动脉造影期间冠状动脉壁的可视化。
在宽容积计算机断层扫描仪上对冠状动脉斑块模型进行扫描。在不同的X射线管电流和电压下测量空间分辨率、对比分辨率和血管壁厚度。
空间分辨率范围为0.385至0.625毫米，在较高电流下显著降低。在较高电流下，对比噪声比显著更高。对于80和100千伏峰值电压，在300和400毫安时以及对于120和135千伏峰值电压在300毫安时，壁厚度测量最为准确。
较高电流下空间分辨率较低是由于焦点尺寸增加导致的模糊增加。由于量子噪声降低，较高电流下对比噪声比更高。在具有中等对比噪声比但最佳空间分辨率的中等电流下，壁厚度测量更准确。为了准确测量冠状动脉壁厚度，要在牺牲对比噪声比的情况下实现最佳空间分辨率。
