64层螺旋CT冠状动脉成像对左心室心肌密度差异的分析

目的 分析64层螺旋CT(MSCT)冠状动脉CT血管成像(CTA)检查中,左心室心肌密度的特征性差异.方法 行64层MSCT冠状动脉CTA检查的连续病例1130例中冠状动脉正常或狭窄程度＜25%的患者共119例.回顾性分析其CT增强扫描重建层厚3mm的横断面图像,选取主动脉瓣下缘平面左心室心肌为测量评价目标,在室间隔后部、前部、心尖、左心室游离壁前部及游离壁后部划5个兴趣区,分别测量其平均CT值,用配对t检验统计方法比较其差异.结果 主动脉瓣下横断面图像中正常人左心室心肌密度值:室间隔后部、前部分别为(93.8±14.8)和(91.9±15.1)HU,心尖部为(69.9±15.5)HU,左心室侧壁前部、后部平均CT值分别为(79.7±16.9)和(88.0±14.3)HU,平均密度呈现为"U"字型.上述5个测量部位中,室间隔前部、后部测量值之间差异无统计学意义(t=0.968,P=0.3339),室间隔前部与心尖部、心尖部与左心室游离壁前部心肌密度差异具有统计学意义(t值分别为11.060和4.639,P值均＜0.01).结论 冠状动脉CTA检查中左心室心肌密度有差异,以心尖部最低,因此,依靠心肌低密度判断心肌梗死时要引起注意.

Spatial heterogeneity of left ventricular myocardium attenuation during 64 multi-slice CT coronary artery angiography

Objeetive To analyze the attenuation differences of left yentricular myocardium on 64-slice CT coronary artery angiography in adults.Methods of 1130 consecutive patients,119 patients (65 males,54 females,ranged from 27 to 83 years with mean age of 52 years)with no stenosis or stenosis less than 25% in the left anterior descending arteries were enrolled.The standard axial image with 3mm slice thickness just below the aorta valve was selected for measttrement.The regions of interest(0.1 cm× 0.1 cm)in posterior interventricular septum(septal P),anterior interventricular septum(septal A),apex,anterior free wall and posterior free wall of the left ventricle were selected within the myocardium and the mean CT value wag measured.A paired Student t test was used for the comparison of CT values in different areas,P value under 0.05 was considered statistically significant.Results The megn attenuafion of the apical region(69.9±15.5)HU was lower than that of septal A(91.9±15.1)HU(t=11.060,P＜0.01)and anterior free wall(79.7±16.9)HU(t=4.639,P＜0.01),the mean attenuation in septal(93.8±14.8)HU and posterior free wall(88.0±14.3)HU showed relatively higher values.The myocardial intensity attenuation presented as a U-shape in the left ventricular myoeardium. Conclusions The mean attenuation in the left ventrieular myoeardium demonstrates as U-shape during the coronary artery angiography examination in normal adults.This can be helpful for iudging the extent of myocardial infarctiotr.