左冠状动脉异常起源于肺动脉的CT诊断

Computed Tomography Imaging in Anomalous Origin of the Left Coronary Artery from the Pulmonary Artery

目的探讨左冠状动脉异常起源于肺动脉(ALCAPA)的CT表现特征。方法回顾性分析CT诊断为ALCAPA并经手术矫正治疗的29例患者的临床和影像资料,着重观察左冠状动脉开口位置、冠状动脉管腔扩张、侧支血管的建立及分布、以及左房室大小、心肌灌注情况。结果 CT对29例ALCAPA均做出明确诊断,清晰显示左冠状动脉起源于主肺动脉,其中21例起源于肺动脉左后窦,2例起源于肺动脉右后窦,1例起源于肺动脉前窦,5例起源于主肺动脉右侧壁;19例可见左冠状动脉向肺动脉内供血,其中13例呈喷射样改变;右冠状动脉迂曲扩张27例,单纯扩张1例,1例管径无扩张,左冠状动脉迂曲扩张13例,单纯扩张14例,2例管径无扩张;10例无明确侧支血管或仅少量侧支血管,19例侧支血管丰富,分布于室间隔、圆锥前、右室侧壁及心脏膈面;心外侧支13例,均为支气管动脉侧支,12例与回旋支相通,1例与前降支相通;13例左室壁心内膜下灌注减低;2例室壁变薄;左心室扩大26例,左心房增大20例;12例左心室乳头肌或腱索钙化;16例肺动脉增宽。结论 CT能够直观显示ALCAPA异常起源的部位,并能够显示出肺动脉内对比剂的喷射征像及染色样改变等提示左向右分流的特征性征象,同时可显示冠状动脉扩张、心内外侧支血管、心肌缺血及左房室增大等伴随的间接改变。

Objective To summarize the CT imaging manifestations of anomalous origin of the left coronary artery from the pulmonary artery（ ALCAPA） in order to make a further understanding of this disease. Methods A retrospective analysis of CT images,clinical data was performed in 29 patients with ALCAPA,who had undergone CTA before some form of surgical correction during their clinical course at Fuwai hospital between January 2009 and August 2014. Results All the29 patients with ALCAPA were directly visualized that the left coronary artery（ LCA） is arising from the main pulmonary artery by CTA,LCA originating from the left posterior sinus of the main pulmonary artery was seen in 21 cases,2 cases from right posterior sinus and one case from the anterior sinus,5 cases from the right lateral aspect of main pulmonary artery above the pulmonary sinus. The blood flow from LCA to the main pulmonary artery was demonstrated in 19 cases,of which,13 cases appeared as a jet entering the main pulmonary. Right coronary artery（ RCA） was dilated and tortuous in 27 cases,single dilated in one case,LCA was dilated and tortuous in 13 cases,single dilated in 14 cases. There was little or no coronary collateral development in 10 cases,19 cases had well-established collateral vessels,distributed in the epicardial surface of the heart or within the interventricular septum. Meanwhile,systemic collateral supply to LCA was seen in 13 cases,all of which were bronchial arteries,12 cases supply to left circumflex branch（ LCX） and one case supply to LAD.During the first pass of contrast material through the left ventricle,myocardial segments with diminished perfusion were seen in 13 cases,wall thinned in 2 cases,left ventricular hypertrophy or dilatation in 26 cases and left atrium dilatation in 20 cases. Chordae or papillary muscles of the left ventricle calcification were detected in 12cases; pulmonary arterial hypertension was seen in 16 cases. Conclusion CT can directly visualize the LCA arising from the main pulmonary artery and show the jet sign and contrast change in the main pulmonary artery. Furthermore,it can display the secondary imaging findings,such as the coronary artery dilatation,intracoronary and extracoronary collateral vessels,myocardial ischemia,left atrium and left ventricle dilatation.