CAJ | 학술논문

目的：采用 MR 动态电影、首过灌注及延迟增强方法,探讨冠状动脉微栓塞动物模型的 MR 特征、分析其演变过程。方法通过心导管介入操作,往家猪左前降支内注射12万个微球(直径42μm),建立家猪冠状动脉微栓塞模型(共11头)。冠状动脉造影术的时间点为基础状态和微栓塞后即刻,MRI 扫描的时间点为基础状态、微栓塞后6 h 和1周。之后,行病理分析,包括 NBT染色和 HE 染色。结果冠状动脉造影术示微栓塞后心外膜大血管无异常。MRI 动态电影示微栓塞心肌节段收缩功能下降,基础状态的室壁收缩增厚率为(42.6±2.0)%,微栓塞后6 h 为(20.3±2.3)%(P <0.001)、微栓塞后1周为(31.5±2.1)%(P <0.001)。MRI首过灌注显示,微栓塞后6 h,微栓塞心肌节段出现低灌注改变,1周后范围缩小。MRI 延迟增强扫描显示,微栓塞后6 h,微栓塞心肌节段出现淡片状异常强化,1周后复查,延迟强化现象消失。大体标本 NBT 染色无肉眼可见的梗死灶,HE 染色显微镜下可见微梗死灶形成。结论冠状动脉微栓塞可造成心肌收缩功能受损,不同阶段的 MR 特征有所不同,联合心脏 MRI 多技术扫描及随访,对于评价冠状动脉微栓塞病变具有一定价值。
목적：채용 MR 동태전영、수과관주급연지증강방법,탐토관상동맥미전새동물모형적 MR 특정、분석기연변과정。방법통과심도관개입조작,왕가저좌전강지내주사12만개미구(직경42μm),건립가저관상동맥미전새모형(공11두)。관상동맥조영술적시간점위기출상태화미전새후즉각,MRI 소묘적시간점위기출상태、미전새후6 h 화1주。지후,행병리분석,포괄 NBT염색화 HE 염색。결과관상동맥조영술시미전새후심외막대혈관무이상。MRI 동태전영시미전새심기절단수축공능하강,기출상태적실벽수축증후솔위(42.6±2.0)%,미전새후6 h 위(20.3±2.3)%(P <0.001)、미전새후1주위(31.5±2.1)%(P <0.001)。MRI수과관주현시,미전새후6 h,미전새심기절단출현저관주개변,1주후범위축소。MRI 연지증강소묘현시,미전새후6 h,미전새심기절단출현담편상이상강화,1주후복사,연지강화현상소실。대체표본 NBT 염색무육안가견적경사조,HE 염색현미경하가견미경사조형성。결론관상동맥미전새가조성심기수축공능수손,불동계단적 MR 특정유소불동,연합심장 MRI 다기술소묘급수방,대우평개관상동맥미전새병변구유일정개치。
Objective To assess the MR characterization of coronary microembolization (CME)in an animal model as well as the evolution using MR cardiac cine,first-pass perfusion,and delay enhancement imaging.Methods Coronary microembolization models were established through intracoronary infusion of 120 000 microspheres (42 μm)into the left anterior descending artery in 1 1 pigs. Coronary angiography was performed at baseline and immediately after the injection of microspheres.MR imaging was carried out at baseline,6 hours,and 1 week after microembolization.Then,postmortem evaluation was performed using NBT and HE staining.Re-sults Coronary angiography after the injection of microspheres showed normal-appearing epicardial arteries in all animals.Coronary microembolization caused a significant decline in systolic wall thickening of the microembolized myocardial segments on cine MR ima-ges [from (42.6±2.0)% at baseline to (20.3±2.3)% at 6 hours and (31.5±2.1)% at 1 week after CME;P < 0.001 for both]. First-pass perfusion deficit was visualized at 6 hours after microembolization,and was less pronounced at 1 week.Hyperenhanced myocardium was found on delay enhancement MRI at 6 hours after microembolization in microembolized segments,but was not shown at 1 week. The microinfarcts were detectable microscopically through HE staining but invisible for the naked eye on gross NBT specimen.Con-clusion Coronary microembolization may cause a persistent decline in myocardial contraction and its MR characterization may vary with different stages.A combined use of different cardiac MRI techniques and follow-up examinations may be helpful for evaluating myocardial impairment due to coronary microembolization.