The Study Of Non-invasive Technology In The Diagnosis Of Coronary Artery Disease

PartⅠThe value of 64-multidetector Computed Tomography in the diagnosis of coronary artery diseaseObjectives:To evaluate 64-multidetector computed tomography(64-MDCT) in the diagnosis of coronary artery stenosis and congenital anomalies.Methods:From 2006/12 to 2008/10,140 patients suspected of coronary artery disease were undergoing 64-MDCT imaging and within one month, coronary angiography(CAG) was performed.All patients were took a dose of 25 mg metoprolol orally one hour before 64-MDCT imaging.Together with the retrospectively ECG-gated reconstruction,some observation methods (including LAO,RAO,LAO Cranial/Caudal,RAO Cranial/Caudal and cross—section) and reconstruction methods(including Maximum Intensity Projection(MIP),Multi-planar Reconstruction(MPR) and Volume Rendering (VR)) were used to image the coronary artery segments,of which the diameter was no little than 1.5mm.The presence of diameter reduction(DS)≥50%in 64-MDCT imaging was considered as significant coronary stenosis, the degree of which was classified as:GradeⅠ,50%≦DS＜70%;GradeⅡ, 70%≦DS＜90%;GradeⅢ,90%≦DS≦99%;GradeⅣ,complete obstruction. Myocardial bridging was diagnosed in 64-MDCT imaging when an intramuscular segment of a coronary artery was visualized on axial and MPR images,covered by myocardial muscle or fibrous-fatty tissue partial or entirely.They were compressed during systole phage and recovery on diasystole phage.All results were compared with CAG.Results:2009 segments can be evaluated by QCA,of which 1863 segments (92.6%) can be evaluable by 64-MDCT.The sensitivity and the specificity to diagnose significant coronary stenosis(DS≧50%) cases was 95.6%(65/68) and 93%(67/72) respectively,the positive and negative predictive value was 92.9%(65/70) and 95.7%(67/70) respectively.The sensitivity and the specificity to diagnose significant coronary stenosis(DS≧50%) segments was 96.6%(141/146) and 98.3%(1688/1717) respectively,the positive and negative predictive value was 82.9%(141/170) and 99.7%(1688/1693) respectively.In addition,the detection sensitivity of GradeⅠ,Ⅱ,ⅢandⅣstenosis were 97.2%,93.1%,96.3%and 100%respectively(P=0.69), the specificity were 99.0%,99.5%,99.8%and 99.9%respectively(P=0.87). The detection sensitivities of significant coronary stenosis differed in different coronary segments(P＞0.05):the highest was seen in LMA(100%), then in LAD(98.7%),RCA(94.5%) and LCX(92.3%).The lowest was in distal LCX(75%) and distal RCA(85.7%).There were 141 segments of GradeⅠ～Ⅲstenosis evaluated by 64-MDCT:77 segments in LAD,24 segments in LCX,35 segments in RCA and 5 segments in LMA.Compared with CAG,23 myocardial bridging cases were found through 64-MDCT,including 21 cases of single myocardial bridging in LAD and 2 cases of dual myocardial bridgings.The sensitivity,specificity,positive and negative predictive value to diagnose myocardial bridging were 92%,98.2%,92%and 98.2%respectively.64-MDCT detected all 12 cases of congenital coronary artery anomalies and malformations correctly.Conclusions:As a non-invasive technology,64-MDCT can image coronary arteries and branches excellently.It can evaluate stenosis,congenital anomalies and malformations correctly.But severe calcification can affect imaging and tend to overestimate the degree of stenosis.PartⅡThe 64-MDCT characteristics of unstable plaques in acute coronary syndrome patients and the related serum marks study.Objectives:To evaluate 64-MDCT in the diagnosis of different coronary plaque and plaque characteristics of acute coronary syndrome(ACS) patients.The value of serum MMP-9,TIMP-1,IL-6,IL-18 and CRP in the diagnosis of ACS also was evaluated. Methods:From 2007/12 to 2008/11,70 patients of coronary artery disease were enrolled.According to clinical symptoms,they were divided into ACS (n=35) group and SAP(n=35) group.These patients were undergoing 64-MDCT imaging and within one month,CAG and IVUS were performed.In 64-MDCT imaging,the density CT measurement(Hounsfield units,HU) was used to determine different types of plaques:soft plaque(≦50HU),fibrous plaque (50-119HU) and calcified plaque(≧12onu).The results were compared with IVUS.IVUS and 64-MDCT analysis included quantitative measurements of cross-sectional area of external elastic membrane(EEM CSA) of the lesion site and at the proximal and distal reference sites.The plaque burden and remodeling index(RI) were also analyzed.Positive remodeling was defined as RI＞1.05 and negative remodeling as RI＜0.95.Serum MMP-9, TIMP-1,IL-6,IL-18 and CRP were evaluated using ABC-ELISA,compared with 35 control subjects(without coronary heart disease).Results:88 segments were evaluated by IVUS,of which 81 segments(92%) can be evaluated by 64-MDCT:56 segments in LAD,5 segments in LCX,18 segments in RCA and 2 segments in LMA.We found 31 soft plaques,18 fibrous plaques,20 calcified plaques and 12 mixed plaque by IVUS.64-MDCT found 30 soft plaques(19±42HU(—22～45HU)),19 fibrous plaques(81±23HU (61～112HU)),20 calcified plaques 302±91HU(175～567HU) and 12 mixed plaques(118±48HU(138～392HU)),P＜0.01.The detection sensitivity of soft plaques,fibrous plaques,calcified plaques and mixed plaques were 90.3%,88.9%,100%and 92.3%respectively(P=0.03).Soft plaque was observed more frequently in ACS group than in SAP group(61.5%vs 14.3%, P＜0.001),including 2 plaque rupture;whereas calcified plaque was more common in SAP group(38.1%vs 7.7%)(P=0.001).Eccentric plaque was observed more frequently in ACS group than in SAP group(71.4%vs 52.5%, P＞0.05).Compared with SAP group,the EEM CSA at the proximal reference sites(15.9±1.8 mm~2 vs 14.8±2.0 mm~2,P=0.039) and distal reference sites (13.1±2.3 mm~2 vs 12.6±2.0 mm~2,P=0.026) were larger in ACS group in 64-MDCT imaging.The mean EEM CSA of reference sites((14.1±1.7 mm~2 vs 13.7±1.6 mm~2,P=0.018),lesion EEM CSA(14.8±2.2 mm~2 vs 13.9±2.1mm~2, P=0.029),the plaque EEM CSA(11.1±2.0 mm~2 vs 9.8±1.8mm~2,P=0.012) and the plaque burden(72.8±8.2 mm~2 vs 67.4±8.1mm~2,P=0.001) were significantly greater in ACS group rather than SAP group,while the lumen EEM CSA(3.7±1.4mm~2 vs 4.3±1.3mm~2,P=0.035) was smaller in ACS group. RI was significantly higher(1.05±0.09 vs 0.99±0.06,P=0.032) and positive remodeling was more frequent in ACS group(61.6%vs 33.3%, P＜0.05).Compared 64-MDCT and IVUS,the correlation coefficients for the EEM CSA at the proximal and distal reference sites,the mean EEM CSA of reference sites were 0.785,0.732 and 0.745 respectively,P＜0.001.The correlation coefficients for the lesion EEM CSA,the lumen CSA,the plaque CSA,the plaque burden and RI were 0.521,0.667,0.711,0.701 and 0.672 respectively,P＜0.05.The serum MMP-9,TIMP-1,IL-6,IL-8 and CRP were significant higher in ACS group than SAP group,P＜0.05.The serum MMP-9, IL-6 and IL-18 were significant higher in SAP group than control group, P＜0.05,but serum TIMP-1 and CRP were similar,P＞0.05.In ACS group,There was no correlation between serum MMP-9 and TIMP-1(r=-0.169,P=0.33),and there was positive correlation between serum MMP-9 and IL-18(r=0.389, P＜0.05).In SAP group,there was positive correlation between serum MMP-9 and TIMP-1(r=0.381,P＜0.05).Conclusions:64-MDCT can identify different coronary plaques based on CT measurement,but may he difficult to differ soft plaques from fibrous plaques.Soft plaque and positive remodeling were observed more frequently in ACS patients.The imbalance of serum MMP-9 and TIMP-1 may be the key point to involve the course of ACS.PartⅢThe value of 64-MDCT in the follow-up of percutaneous coronary intervention(PCI) stenting patientsObjectives:To evaluate the application of 64-MDCT in the follow-up of percutaneous coronary intervention(PCI) stenting patients with the attention to in- stent restenosis(ISR). Methods:From 2008/4 to 2008/11,35 patients with prior percutaneous coronary intervention and coronary stent implantation referred for repeated QCA underwent 64-MDCT imaging.And no more than one month later, they received QCA.All the patients didn't have arrhythmia,renal failure (Cr＜120mmol/L) or heart failure(Grade＜3).Together with the retrospectively ECG-gated reconstruction,Maximum Intensity Projection (MIP),Multi-planar Reconstruction(MPR) and Volume Rendering(VR) were used to reconstruct every segment of the coronary artery.Based on contrast enhancement and attenuation in the lumen of stented segments, the presence of diameter reduction≧50%was considered as ISR after PCI stenting.All the results were compared with that of QCA.Results:43 stents from 32 cases were included,14 ISR after PCI stenting were found by QCA,of which 64-MDCT could detect 13 ISR and rule out 25 non-ISR correctly.The sensitivity,specificity,the positive and negative predictive value of 64-MDCT were 92.8%(13/14),86.2%(25/29), 76.4%(13/17) and 96.1%(25/26) respectively.Conclusions:64-MDCT may be a non-invasive follow-up method to evaluate if there exists ISR after PCI stenting,especially in the patients no ISR existing clinically.