Groen Jaap M, Greuter Marcel J W, van Ooijen Peter M A, Willems Tineke P, Oudkerk Matthijs
Department of Radiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
J Comput Assist Tomogr. 2006 Sep-Oct;30(5):812-7. doi: 10.1097/01.rct.0000226398.43235.6f.
Evaluation of the image quality of coronary artery stents at various heart rates using Multi Detector Computed Tomography (MDCT).
Nine different coronary stents were attached to a moving heart phantom and scanned using a 64-MDCT with a rotation time of 330 milliseconds (ms). The heart rate of the phantom was varied between 0 and 115 beats per minute (bpm). Two independent methods were used to investigate image quality. After reconstruction the average Houndsfield Unit (HU) value in the stent lumen was measured in the longitudinal and the cross-sectional plane. The stent images were then presented to two radiologists. The radiologists were asked to rank the images from good to bad based on lumen visibility and overall image quality. A second ranking was obtained using the CT density values. Finally two rankings were compared.
Compared to the value for air, the HU-values measured in the lumen increased by 50 to 700 HU. Average slope value in the longitudinal plane was 1.7 +/- 0.6 HU/bpm, and the average slope value in the cross-sectional plane was 1.7 +/- 0.8 HU/bpm. This shows increased attenuation with increasing heart rate and thus a negative correlation between image quality and heart rate in both planes for all stents. The ranking acquired from the radiologists resembled the measured results as they also showed a negative correlation between the two variables. Using the results of the CT density measurements an analysis was done on multi-segment reconstruction (MSR).
A negative correlation between the heart rate and image quality of coronary stents was found by two independent methods. MSR showed no benefit for image quality in this study.
使用多排螺旋计算机断层扫描（MDCT）评估不同心率下冠状动脉支架的图像质量。
将九个不同的冠状动脉支架附着在一个运动的心脏模型上，使用旋转时间为330毫秒（ms）的64排MDCT进行扫描。模型的心率在每分钟0至115次心跳（bpm）之间变化。使用两种独立的方法来研究图像质量。重建后，在支架管腔的纵向和横截面上测量平均亨氏单位（HU）值。然后将支架图像呈现给两位放射科医生。要求放射科医生根据管腔可见性和整体图像质量将图像从好到差进行排序。使用CT密度值获得第二个排序。最后比较两个排序结果。
与空气值相比，管腔内测量的HU值增加了50至700 HU。纵向平面的平均斜率值为1.7 +/- 0.6 HU/bpm，横截面上的平均斜率值为1.7 +/- 0.8 HU/bpm。这表明随着心率增加衰减增加，因此所有支架在两个平面上图像质量与心率之间呈负相关。放射科医生获得的排序与测量结果相似，因为它们也显示了这两个变量之间的负相关。使用CT密度测量结果对多段重建（MSR）进行了分析。
通过两种独立的方法发现心率与冠状动脉支架图像质量之间存在负相关。在本研究中，多段重建（MSR）对图像质量没有益处。
