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目的比较不同重建时相间隔及重建层厚对左心室舒张末期容积(EDV)、收缩末期容积(ESV)及射血分数(EF)的影响,优化重建方案。方法回顾性分析20例冠状动脉CTA检查的患者资料,将患者原始CT数据分别重建为层厚0.625、1.25、2.5mm的横断面图像,并以心动周期的10%和5%为间隔拆分为10和20个时相。利用图像工作站中基于CT值的容积分割算法计算舒张末期及收缩末期左心室容积以及左心室射血分数(LVEF),比较不同重建时相间隔和不同重建层厚左心室容积测量值的差异。结果 2.5mm获得的左心室容积测量值为,EDV(142.4±24.8)ml,ESV(48.9±16.9)ml;小于0.625mm[EDV(152.5±26.6)ml,ESV(56.9±19.5)ml]及1.25mm的值[EDV(152.3±26.3)ml,ESV(56.6±21.3)ml,P<0.001]。LVEF2.5mm的测量值大于0.625及1.25mm的值[(66.4±6.5)%vs.(63.3±7.5)%,(63.7±8.7)%,P<0.001]。不同重建时相间隔获得的左心室收缩末期容积存在差异,以间隔5%的心动周期时相获得的结果小于间隔10%重建的结果(P<0.01)。左心室舒张末期容积两者之间无显著性差异。两种重建方法获得的LVEF存在差异,间隔5%重建获得的LVEF值大于间隔10%重建的结果(P<0.01)。结论 64排螺旋CT能够以不同重建时相间隔和图像层厚获得左心室容积数据。较大的重建层厚和较少重建时相间隔可减少后处理图像数量,但导致低估或高估左心室容积。
Objective To compare the effects of interval and remodeling thickness on left ventricular end-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (EF) at different reconstruction and to optimize the reconstruction plan. Methods The data of 20 patients with coronary artery CTA were retrospectively analyzed. The original CT data of the patients were reconstructed to 0.625, 1.25 and 2.5 mm thick slice images, respectively, and divided into 10% and 5% intervals of cardiac cycle 10 and 20 phases. The left ventricular volume and left ventricular ejection fraction (LVEF) at end-diastole and end-systole were calculated by volume fractionation algorithm based on CT value in image workstation. The differences of LV volume measurements at different reconstruction intervals and different reconstruction thickness were compared. Results Left ventricular volume measurements obtained at 2.5 mm were EDV (142.4 ± 24.8) ml, ESV (48.9 ± 16.9) ml, less than 0.625 mm [EDV (152.5 ± 26.6) ml, ESV mm [EDV (152.3 ± 26.3) ml, ESV (56.6 ± 21.3) ml, P <0.001]. The measurement of LVEF 2.5 mm was greater than the values 0.625 and 1.25 mm [(66.4 ± 6.5)% vs (63.3 ± 7.5%, (63.7 ± 8.7)%, P <0.001). There was a difference in LV end-systolic volumes obtained at intervals of reconstructions, with results obtained at 5% intervals in the cardiac phase less than those at 10% intervals reconstructed (P <0.01). There was no significant difference between left ventricular end-diastolic volumes. There was a difference in LVEF between the two reconstructions, with LVEF obtained at 5% interval reconstruction being greater than at 10% interval reconstruction (P <0.01). Conclusion 64-slice spiral CT can obtain the left ventricular volume data at different reconstruction interval and image thickness. Larger reconstructed layer thicknesses with less reconstruction interval reduce the number of post-processing images, but result in underestimation or overestimation of left ventricular volume.