The Diagnostic Value Of Dual-source CT For Evaluation Of Coronary Artery Disease

【Objective】In clinical research,the diagnose of the patients suspected coronary artery disease(CAD)which had high-risk factors or the narrow degrees of the coronary artery confirmed the CAD,depended on selected coronaryangiography(SCAG),which was traumatic.SCAG was considered the standard of reference diagnosing CAD or not, but it had many disadvantages,such as expensiveness,complicated operation,traumatic,hospitalization and so on.Some patients did not adopted even rejected this examination,and that,the 20%～27%of the patients' coronary were normal or slightly pathological. In addition,SCAG was limited to diagnose the stability of atherosclerotic plaques,myocardial bridges(MB),coronary artery fistu]a(CAF).Therefore,people were searching more available methods.The purpose of our study was to determine the performance of the latest dual-source computed tomography(DSCT)coronary angiography in diagnosing coronary artery disease in comparison to SCAG in patients without heart rate control.【Materials and methods】1023 patients(672 men,351 women;mean age 63±11years;age range 39～79years)in our hospital underwent DSCT coronary angiography and 85 patients suspected CAD in them SCAG within 28 days.Exclusion criteria for DSCT were arrhythmfc,allergy to iodine containing contrast medium,renal insufficiency (creatinine level＞120μmol/L),pregnancy,hemodynamic instability. Symptoms and cardiovascular risk factors of all patients had no statistical difference.The study protocol was approved by our local ethics committee and all participating patients gave written informed consent.All DSCT examinations were performed on a DSCT scanner (Somatom Definition,Siemens Medical Solutions,Forchheim, Germany).The contrast medium of 80 ml of Iopromide370(made in Schering Pharmaceutical Ltd,China)followed by 50 ml saline solution was injected into an antecubital vein via an 18-gauge catheter by injecting rate 5 ml/s.Data acquisition was performed from 1 cm below the level of the tracheal bifurcation to the diaphragm in a cranio-caudal direction.Irrespective of the individual heart rate and the heart rate variability,no beta-blockers were given prior to the scan except oral beta-blockers as part of their baseline medication.All reconstructed images were evaluated and classified by two independent readers using thin-slab maximum intensity projection (MIP),curved planar reconstruction(CPR),volume rendering(VR), and multi-planar reformations(MPR)on a per-segment basis.All reconstructed images were transferred to a dedicated workstation (Wizard,Siemens Medical Solutions)equipped with dedicated cardiac post-processing software(Syngo Circulation,Siemens Medical Solutions).The segments mainly include right coronary artery(RCA),left main(LM),left anterior descending artery (LAD),left circumflex artery(LCX)andbiggish intermedial artery, if present.Two experienced radiologists independently assessed image quality of all coronary segments using a three-point score: 1,excellent(no artifact,unrestricted evaluation);2,good (minor or moderate artifacts,but can diagnose);and 3,not assessable(severe artifacts impairing accurate evaluation).The calcium scores were measured according to Agatston's method.SCAG was performed on a INNOVA2000(GE,American)according to standard Judkin's techniques.The results were assessed by one experienced intercurrent expert who was blinded to the results of the DSCT coronary angiography.【Result】1.Without heart rate control,DSCT provided us excellent image quality,the mean scores was 1.1±0.25.There was not statistical different in LM,LAD,LCX and RCX.DSCT coronary angiography provides a high diagnostic accuracy for the evaluation of CAD.Overall sensitivity,specificity,positive and negative predictive value for evaluating CAD were 96.8%, 96.9%,93.7%,and 99.4%,and heart rates does not affect diagnostic accuracy.2.Coronary artery calcification(CAC)scores elevated with the process of aging;DSCT examination can delineate the composition of atherosclerotic plaques;the scores of CAC were obviously relational with the symptoms of the CAD.3.The diagnosis of myocardial bridges and coronary artery fistula became easier with DSCT coronary angiography.4.DSCT was limited for chronic total obstructions(CTO),but can evaluate the lengths of them.【Conclusion】1.DSCT coronary angiography provided a high diagnostic accuracy or the evaluation of CAD without heart rate control.2.It was important to quantitate CAC which could estimate the stability of the atherosclerotic plaques.3.DSCT is a better imaging technique that provides a noninvasive tool for MB and CAF.4.DSCT coronary angiography had a considerable advantage with chronic total obstructions.