Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 388-1 Pungnap-2-dong, Songpa-gu, Seoul, 138-736, Republic of Korea.
Int J Cardiovasc Imaging. 2010 Feb;26 Suppl 1:103-9. doi: 10.1007/s10554-010-9586-3. Epub 2010 Jan 30.
Interpolation artifact is known to occur when the heart rate is decreased lower than the critical value for the specific pitch. The purpose of our study is to determine the minimum heart rate (minHR) for the specific pitch that provides images without interpolation artifact when using dual-source computed tomography (DSCT). We scanned the 'thin slice thickness block' of the CT performance phantom provided by the American Association of Physicists in Medicine using DSCT for variable pitches. Change in heart rate was simulated through ECG editing by changing R-R interval. Axial, sagittal, and coronal image sets were reconstructed and assessed for the presence and extent of interpolation artifact. MinHR at which no interpolation artifact was detected for each pitch value was determined. Length of interpolation artifact (LOA) on sagittal view was also measured when the heart rate was simulated at 10 bpm lower than the minHR on each pitch setting. MinHRs for each pitch value were 9-10 bpm from the estimated heart rate. However, minHR for the lowest pitch value 0.2, estimated heart value 40 bpm was 37 bpm. LOA was larger in the low heart rate condition. Measured values of minHR were correlated exactly with the calculated values. MinHRs that provide images without interpolation artifact for each pitch value when using DSCT were determined. The concept of minHR is important for obtaining high quality images of cardiac CT angiography when using DSCT.
当心率低于特定音高的临界值时，已知会出现内插伪影。我们研究的目的是确定在使用双源计算机断层扫描 (DSCT) 时，提供无内插伪影图像的特定音高的最小心率 (minHR)。我们使用 DSCT 对美国医学物理学家协会提供的 CT 性能体模的“薄切片厚度块”进行扫描，使用不同的音高。通过改变 R-R 间隔来编辑 ECG 来模拟心率变化。重建轴、矢状和冠状图像集，并评估是否存在和程度的内插伪影。确定了在每个音高值下检测到无内插伪影的最小心率 (minHR)。当心率在每个音高设置下模拟比 minHR 低 10 bpm 时，测量矢状视图上的内插伪影长度 (LOA)。每个音高值的 minHR 比估计心率低 9-10 bpm。然而，最低音高值 0.2 的 minHR 为 37 bpm，估计心率为 40 bpm。在低心率条件下，LOA 更大。测量的 minHR 值与计算值完全相关。确定了在使用 DSCT 时，每个音高值提供无内插伪影图像的 minHR。在使用 DSCT 进行心脏 CT 血管造影时，minHR 的概念对于获得高质量的图像非常重要。
