【作者】 鲁锦国；

【导师】 蒋世良； 吕滨； 郑宏； 徐仲英；

【作者基本信息】 中国协和医科大学 ， 影像医学与核医学， 2009， 博士

【摘要】 第一部分对比剂不同注射方案在64层螺旋CT冠状动脉造影应用中的研究【摘要】目的比较不同的对比剂注射方案,以选择最佳的64层螺旋CT冠状动脉造影注射方案。方法将150例患者按数字表法随机分为以下5组:组1为单时相(单纯注射对比剂),组2为双时相(对比剂注射完后注射生理盐水),组3A、3B、3C为三时相(在注射对比剂和生理盐水注射时相之间加入稀释对比剂注射时相,即同时注射对比剂和生理盐水,其比例依次为3:7、5:5和7:3)。各组病例对比剂为均使用碘海醇(350mgI/ml)。分别测量右心房、右心室、左心房、左心室、升主动脉、左右冠状动脉CT值,采用单因素分析(anova)比较其差异。评估图像质量和上腔静脉伪影,采用卡方检验比较其差异。结果各组间总对比剂用量差异有统计学意义(F=27.43,P＜0.001),组3B与组1、3C差异无统计学意义(P=0.18;P=0.25),组2与组3A对比剂注射总量差异也无统计学意义(P=0.06),其余各组两两比较差异均有统计学意义(P＜0.05)。组2对比剂用量最少,为59.9±4.9mL,其次为组3A,为62.9±3.2mL。5组病例中,冠状动脉图像质量差异有统计学意义(χ~2=18.81 P=0.016)。组1图像质量最佳,评分为4分为22例。其次为组2和组3A,图像质量评分为3分和4分之和分别为26例和24例,两组图像质量无显著性差异(χ~2=0.48,P=0.79)。各组产生的上腔静脉伪影差异有统计学意义(F=31.44,P＜0.001),产生伪影以组1最多,共21例,组2最少,仅1例。组2冠状动脉CT值较其它组明显高(F=29.41,P＜0.001),其余各组间左右冠状动脉CT值差异无统计学意义(P＞0.05)。在5组中,组3A显示右心系统最好。结论在64层冠状动脉造影扫描中,在减少造影剂用量和上腔静脉伪影方面,双时相和三时相注射方案优于单时相注射方案;在显示右心系统方面,三时相注射方案优于双时相注射方案。第二部分64层螺旋CT冠状动脉支架检测的实验研究【摘要】目的64层MSCT采用不同的扫描方式及扫描电流对不同扫描位置的支架显示的影响。方法在扫描床偏离中心位置0.0cm、2.5cm、5.0cm、7.5cm和10.0cm的情况下,分别采用回顾性心电门控螺旋扫描方法(管电流为400mA、600mA)和非心电门控轴位扫描方法(管电流为350mA)对18个冠状动脉支架模型(10个支架内设有50%的狭窄)进行成像,测量支架管腔绝对测量值、支架内CT值、支架内噪声、支架周围水的CT值和水的噪声。结果(1)扫描床偏离中心的距离与支架管腔绝对测量值、支架内模拟斑块的可视比例呈负相关,相关系数分别为—0.71、—0.78(P＜0.01)。支架内CT值、支架内噪声以及支架周围水的噪声与扫描床偏离中心距离成正相关,其相关系数分别为0.39、0.11、0.46(P＜0.01)。(2)不同的扫描方式和管电流对支架管腔绝对测量值、支架管腔相对值、支架管腔内CT值、支架管腔内噪声、支架周围水的CT值以及支架内模拟斑块的可视比例的影响差异无统计学意义(P＞0.05),对支架周围水的噪声影响差异有统计学意义(P＜0.01)。结论本研究显示扫描床的位置对支架管腔的显示产生影响,提示行冠状动脉扫描时,尽量将心脏置于机架中心位置。不同的扫描方式和管电流对支架管腔显示的影响较小。MSCT对评价支架内中等密度斑块受限。第三部分不同形态冠状动脉钙化与冠状动脉狭窄的多层螺旋CT相关性研究【摘要】目的探讨64层螺旋CT冠状动脉造影图像上不同形态的冠状动脉钙化与局部管腔狭窄的关系。方法回顾性分析111例冠状动脉钙化患者的CT冠状动脉造影和传统冠状动脉造影图像。依据冠状动脉长轴和短轴方向上冠状动脉钙化形态对钙化灶进行分类。长轴方向的冠状动脉钙化灶分为:点状钙化、结节状、条状钙化、条块状钙化。短轴方向的冠状动脉钙化灶分为:点状钙化、新月形钙化、半月形钙化、满月形钙化、环形钙化。通过CTA和CAG点对点的评价,分析不同形态的冠状动脉钙化同局部管腔狭窄的关系。结果共分析了528个节段钙化灶,其中383个节段(72.5%)为点状钙化,145个节段(27.5%)为非点状钙化。所有点状钙化本身未造成局部冠状动脉狭窄。34个节段冠状动脉非点状钙化造成局部管腔重度狭窄,占非点状钙化灶的23.5%。不同形态的冠状动脉钙化斑块造成局部管腔重度狭窄的比例差异均有统计学意义(P＜0.01)。从冠状动脉长轴方向看,造成冠状动脉局部管腔重度狭窄34个节段钙化灶中,结节状钙化、条状钙化及条块状钙化节段分别有4(11.8%)、8(23.5%)、22(64.7%)个。42.3%(22/52)的条块状钙化造成管腔重度狭窄。从冠状动脉短轴方向看,造成冠状动脉局部管腔重度狭窄的新月形、半月形、满月形及环形钙化节段分别有0(0.0%)、8(23.5%)、18(52.9%)、8(23.5%)个。66.7%(18/27)的满月形钙化和66.7%(8/12)环形钙化造成管腔重度狭窄。结论冠状动脉CTA显示的不同形态的钙化斑块造成局部管腔的狭窄程度不同。冠状动脉长轴方向上的条块状钙化和短轴方向上的满月型钙化、环形钙化是造成局部冠状动脉重度狭窄的主要原因。第四部分双源CT前瞻性心电门控冠状动脉造影:与传统冠状动脉造影对照【摘要】目的评价双源CT(DSCT)前瞻性心电门控冠状动脉造影(CTCA)对冠状动脉病变诊断的准确性和可行性。方法选取同期行前瞻性心电门控CTCA(扫描前心率低于75次/分)和传统冠状动脉造影(CAG)的30例连续患者作为研究对象。另选取同期行回顾性心电门控CTCA和CAG的45例连续患者作为对照。两名CT医师和两名造影医师依冠状动脉狭窄程度(0:冠状动脉无狭窄;1:冠状动脉狭窄＜50%;2:冠状动脉狭窄≥50 9,6,但＜75%:3:冠状动脉狭窄≥75%;4:冠状动脉狭窄=100%)分别对CTCA和CAG图像进行诊断。两名CT医师还对CTCA的图像质量进行评估,记录辐射剂量。比较前瞻性和回顾性心电门控CTCA的诊断准确性、辐射剂量和图像质量。结果对患者冠状动脉病变的诊断,前瞻性和回顾性心电门控CTCA的差异无统计学意义,其敏感性分别为100.0%、97.4%(P=0.86),特异性分别为66.7%、100.0%(P=0.65),阳性预测值分别为96.4%、100.0%(P=0.89),阴性预测值分别为100.0%、87.5%(P=0.43),诊断准确性分别为96.7%、97.8%(P=0.66);对分支冠状动脉病变的诊断,两者的差异也无统计学意义,其敏感性分别为95.9%、91.1%(P=0.46),特异性分别为97.2%、97.0%(P=0.85),阳性预测值分别为95.9%、96.0%(P=0.66),阴性预测值分别为97.2%、93.2%(P=0.41),诊断准确性分别为96.7%、94.4%(P=0.53);对节段冠状动脉病变的诊断,两者的差异同样也没有统计学意义,其敏感性分别为90.5%、91.2%(P=0.92),特异性分别为98.4%、99.3%(P=0.35),阳性预测值分别为91.8%、96.6%(P=0.26),阴性预测值分别为98.1%、98.0%(P=0.92),诊断准确性分别为97.1%、97.7%(P=0.62)。前瞻性心电门控CTCA的图像质量同同顾性心电门控CTCA的类似(3.3±0.5与3.2±0.3:P=0.23)。同回顾性心电门控CTCA比较,前瞻性心电门控CTCA能降低71%的辐射剂量(3.1mSv±1.3与10.8 mSv±4.6,P＜0.01)。结论在心率低于75次/分,心律稳定的情况下,DSCT前瞻性心电门控冠状动脉造影能获得与回顾性心电门控冠状动脉造影相同的诊断准确性,图像质量也无差别,但是辐射剂量大大降低。第五部分北京自然人群冠状动脉钙化的调查研究【摘要】目的了解北京地区自然人群冠状动脉钙化的发病情况,为临床采用冠状动脉钙化对冠心病危险因素分层和对冠状动脉钙化进一步研究提供基础数据。方法在北京地区随机分层抽取1800例自然人群进行64层螺旋CT冠状动脉钙化扫描。计算冠状动脉钙化积分的人群分布情况及不同年龄和性别人群的钙化分布。结果共1548名入选本课题的北京居民在我院行冠状动脉钙化CT平扫,年龄为53.3±7.8岁,共461名受检者(29.8%)检测出冠状动脉钙化。男性冠状动脉钙化的发病率(37.7%,270/716)较女性的高(23.0%,191/832)(p＜0.001)。男女钙化积分(77.5±252.0)明显高于女性的(37.8±178.9)(p＜0.05)。男女冠状动脉钙化积分均随年龄的增长而增加(p＜0.05)。男女的钙化积分均与年龄和糖尿病密切相关(p＜0.05),女性的冠状动脉钙化积分与高血压密切相关(p＜0.001)。结论北京地区自然人群的冠状动脉钙化发病率及程度随年龄增长而增加,男性的冠状动脉钙化发病率及程度均较同龄女性高。冠状动脉钙化的发展规律及同临床冠心病事件的关系有待进一步研究。更多还原

【Abstract】 Part 1 Different contrast injection protocols for noninvasive 64-slice computed tomographic coronary angiographyObjectives To determine the optimal contrast injection protocol for 64-slice computed tomographic coronary angiography.Methods One hundred and fifty consecutive patients scheduled to undergo retrospectively electrocardiographically gated 64-slice computed tomography.Each 30 patients were assigned to use a different contrast protocols:group 1:uniphasic protocol(contrast injection without saline flush); group 2:biphasic protocol(contrast injection with saline flush);group 3A,3B and 3C: triphasic protocol(contrast material+different saline diluted contrast material+saline flush).Attenuation was measured in the right atrium,right ventricle,left atrium,left ventricle,ascending aorta,right coronary artery and left coronary artery was evaluated and analyzed by s one-way analysis of variance test(ANOVA).The quality of the coronary artery image was evaluated and compared using person Chi-square.Results Among the triphasic protocol groups,group 3A(30%:70%contrast material-saline mixture was used in second phase) used the least contrast material and had the least frequency of streak artifacts,but there were no significant differences in coronary artery attenuation,image quality,visualization right and left heart structures respectively.Among the uniphasic protocol group(group 1),biphasic protocol group (group 2) and triphasic protocol subgroup(group 3A),there were no significant differences in image quality scores of coronary artery(P=0.18);uniphasic protocol group had the highest frequency of streak artifacts(20 cases)(P＜0.05) and had the most amount contrast material(67.0±5.3 ml);biphasic protocol group had the least amount of contrast material(59.9±4.9 ml)(P＜0.05) and had the highest attenuation of left main coronary artery and right coronary artery(P＜0.01),but had the least amount of clear visualization right heart structure(6 cases);triphasic protocol group(group 3A) had the most amount of clear visualization right heart structures(29 cases) were the most among the three groups(P＜0.05).Conclusions Biphasic protocol are superior to the traditional uniphasic protocols for using the least total contrastmedia,having the least Streak artifacts and without image quality degradation.Triphasic protocol (30%:70%contrastmedia-saline mixture was used in second phase) are superior to for clearly visualization of both left ventricle and right ventricle cavities without contrast material volume increase and image quality degradation.Part 2 Evaluation of Coronary Stents In Vitro With 64-slice Computed TomographyObjectives To assess the visualization of different coronary artery stents and the delineation of in-stent stenosis using 64-slice computed tomography (MSCT) with different scan modes when it were placed at different positions.Methods A total of 18 different coronary stents(10 stents with lumen diameter stenosis of 50%) were placed in a vascular phantom and scanned with a 64-slice computed tomography at the distance of 0 mm,25mm,50mm,75mm,and 100mm from the centre of scanner to the phantom.The scan modes were retrospective ECG gating helical scan(tub current:400mA and 600mA) and non-ECG triggering axial scan(tube current:350mA). Visible lumen diameter and attenuation in the stented segments of the phantom were measured.Two readers assessed stenosis delineation.Results(1)The visible lumen diameter and percent of the visible in-stent stenosis had significantly negative correction with the distance between the center of scanner and the phantom(r=-0.71, -0.78 respectively)(all P＜0.01).The attenuation of stent lumen,the attenuation of the water around the stent and the noise of the water around the stent had significantly positive correction with the distance between the center of scanner and the phantom (r=0.39,0.11,0.46 respectively).(2) Different scan mode and different tube current had no effect on the visible lumen diameter,the attenuation of stent lumen,the percent of the visible in-stent stenosis and the attenuation of the water around the stent (P＞0.05),but had effect on the noise of the water around stent(P＜0.01)。Conclusion The distance between the center of scanner and the stents has effect on the display of the stents.The scan mode has little effect on the display of the stent.MSCT Shows limit value in detecting in-stent restenosis. Part 3 Study of Morphological Characteristics of Calcified Plaques and Lumenal Stenosis On 64-slice Computed Tomographic Coronary AnigiographyObjective To research the morphological characters of coronary artery calcified plaque and it’s relation to the degree of stenosis of local coronary artery lumen by multi-slice computed tomography.Methods One hundred and eleven patients who had received 64-slice computed tomographic coronary angiography and conventional coronary angiography(CAG) were found calcified plaques burden.The calcified plaques were classified as punctate,nodular,strip-like and nubbly in long-axis view,and were classified as crescent,semilunar,round moon and circinate in short-axis view.The morphologic characters of these calcification plaques were retrospectively analyzed.The stenosis degree of the corresponding coronary artery lumen was judged in accordance with the results of CAG.Severe stenosis was defined as stenosis of≥75%of the luminal diameter.Results Totally 528 calcified plaque segments were analyzed in coronary computed tomography angiography(CTA) in these 111 patients.Among these there were 383(72.5%) punctate calcified plaque segments and 145(23.5%) non- punctate calcified plaque segments.No obvious stenosis in coronary artery was caused by punctate calcified plaques.There were 34 non-punctate calcified plaques which caused severe stenosis.The ratio of different morphological coronary artery calcification which caused sever stenosis was significant different(all p＜0.01).There were 4 nodular calcified plaques,8 stripe-like calcified plaques and 22 nubbly calcified plaques which caused severe stenosis.42.3% (22/52) nubbly calcified plaque caused severe stenosis.At the same time,there were 0 crescent calcified plaques,8 semilunar calcified plaques,18 round moon calcified plaques and 8 circinate calcified plaques which caused severe stenosis.66.7%moon calcified plaque and circinate calcified plaques caused severe stenosis.Conclusion Different coronary artery calcified plaques generate different degree of stenosis of local coronary artery lumen.Severe stenosis are mostly caused by nubbly calcified plaque(long-axis view),moon calcified plaque(short-axis view) and circinate calcified plaque(short-axis view). Part 4 Prospective ECG triggering for dual-source CT coronary angiography:Comparison with conventional coronary angiography.Objective To evaluate the accuracy and feasibility of dual-source computed tomography coronary angiography(CTCA) using prospective ECG triggering for the assessment of coronary artery disease(CAD).Methods A tall of 30 patients with heart rate less than 75 beats per minute underwent prospective ECG triggering and conventional coronary angiography(Study group) and 45 patients underwent retrospective ECG gating and conventional coronary angiography(Control group).Two independent radiologists assessed the severity of stenosis of CT coronary angiograms,and two independent cardiologists assessed the severity of stenosis of conventional angiograms.All of them used blinging method.Effective radiation doses were calculated and image quality was valuated.Results The differences in diagnostic performance on a per-patient basis between prospective CT angiography and retrospective CT angiography were not significantly different:sensitivity was 100.0%,97.4%,respectively(P=0.86);specificity was 66.7%,100.0%,respectively (P=0.65);PPV was 96.4%,100.0%,respectively(P=0.89);NPV was 100.0%,87.5%, respectively(P=0.43);diagnostic accuracy was 96.7%,97.8%,respectively(P=0.66). Similarly,no level of significance was reached on a per-vessel analysis:sensitivity was 95.9%,91.1%,respectively(P=0.46);specificity was 97.2%,97.0%,respectively (P=0.85);PPV was 95.9%,96.0%,respectively(P=0.66);NPV was 97.2%,93.2%, respectively(P=0.41);diagnostic accuracy was 96.7%,94.4%,respectively(P=0.53). In the same way no level of significance was reached on a per-segment analysis sensitivity was 95.9%,91.1%,respectively(P=0.46);specificity was 97.2%,97.0%, respectively(P=0.85);PPV was 95.9%,96.0%,respectively(P=0.66);NPV was 97.2%,93.2%,respectively(P=0.41);diagnostic accuracy was 96.7%,94.4%, respectively(P=0.53) when comparing prospective CT angiography and retrospective CT angiography.Consensus-determined image quality in coronary artery branches was similar between prospective CT angiography and retrospective CT angiography (3.3±0.5 vs 3.2±0.3,respectively;P=0.23).Calculated effective dose with prospective CT angiography was 71%lower than that with retrospective CT angiography(3.1mSv±1.3 vs 10.8 mSv±4.6,respectively;P＜0.01).Conclusion Prospective CT angiography can reduce radiation dose below that of retrospective CT angiography,while maintain image quality and the ability to assess luminal obstructions in patients with a stable heart rates of less than 75 beats per minute.Part 5 Prevalence of coronary artery calcium among natural population in BeijingObjective To investigate prevalence and amount of CAC as determined by Multi-slice computed tomography(MSCT) in Beijing community natural population.Methods A stratified random sample of 1800 community natural residents in Beijing was enrolled in the study.All subjects would undergo non-enhanced coronary scan by retrospectively ECG-Gated MSCT.Agatston scoring was used for CAC.Coronary artery calcium score(CACS) was calculated for each subject.Groups were compared with respect to age,gender.Results There were 1548 subjects(53.3±7.8 years) enrolled in our study.CAC was found in 29.8%(461/1548) of the subjects.The prevalence of CAC was significantly higher in male subjects (37.7%,270/716) than female subjects(23.0%,191/832)(p＜0.001).The CACS of male subjects and female subjects were 77.5±252.0 and 37.8±178.9,respectively.It was significantly higher in males than females(p＜0.05).The CACS increased significantly with increasing age in males and female subjects(p＜0.05).In the study, age and mellitus diabetes were significantly associated with CACS in both men and women(all p＜0.05).Additionally,hypertension showed significant associations with CACS in women only(p＜0.001).Conclusion There is an increase in the prevalence and amount of coronary artery calcification with age in Beijing community population. Males have significantly higher prevalence and amount of CAC than females.The development of CAC of Chinese and it’s relation to the cardiac events should be studied further.更多还原