The effect of heart rate,vessel angulation and acquisition protocol on the estimation accuracy of calcified artery stenosis in dual energy cardiac CT: A phantom study

PurposeTo investigate the effects of heart beat rate (bpm), vessel angulation and acquisition protocol on the estimation accuracy of calcified stenosis using a dual-energy CT scanner.MethodsA thorax semi-anthropomorphic phantom coupled with a motion simulator and a vessel phantom representing a 50% coronary artery calcified stenosis, were used. Electrocardiograph (ECG)-synchronized acquisitions were performed at different bpms. Acquisitions were performed using A, B, and C single-energy and D dual-energy protocols. Protocol A was prospective ECG-triggered axial and protocols B and C were retrospective single- and two-segment reconstruction ECG-gated helical acquisitions. Protocol D was prospective ECG-triggered axial acquisition. The vessel phantom was placed at two angulations relative to z-axis. Images were reconstructed using all available kernels with iterative reconstruction. Stenosis-percentage was estimated using the CT vendor’s vessel analysis tool. Effective dose (ED) was estimated using the dose-length product method.ResultsIn protocols A, B, and C, measured Stenosis-percentage increased with bpm. Stenosis-percentage estimate ranged from 56.8% at 40 bpm to 62.6% at 100 bpm. In protocol D, Stenosis-percentage ranged from 59.3% at 40 bpm to 54.8% at 80 bpm. Stenosis-percentage was overestimated on respect to the nominal value in most kernels. The detail kernel exhibited the highest accuracy. Stenosis-percentage was not affected by the vessel angulation. ED for protocols A, B, C, and D was 2.4 mSv, 5.1 mSv, 5.5 mSv, and 2.8 mSv, respectively.ConclusionsUse of the dual-energy cardiac CT examination protocol along with the detail kernel is recommended for a more accurate assessment of Stenosis-percentage.     

A head-to-head comparison between CT- and IVUS-derived coronary blood flow models

The goal of this work is to compare coronary hemodynamics as predicted by computational blood flow models derived from two imaging modalities: coronary computed tomography angiography (CCTA) and intravascular ultrasound integrated with angiography (IVUS). Criteria to define boundary conditions are proposed to overcome the dissimilar anatomical definition delivered by both modalities. The strategy to define boundary conditions is novel in the present context, and naturally accounts for the flow redistribution induced by the resistance of coronary vessels. Hyperemic conditions are assumed to assess model predictions under stressed hemodynamic environments similar to those encountered in Fractional Flow Reserve (FFR) calculations. As results, it was found that CCTA models predict larger pressure drops, higher average blood velocity and smaller FFR. Concerning the flow rate at distal locations in the major vessels of interest, it was found that CCTA predicted smaller flow than IVUS, which is a consequence of a larger sensitivity of CCTA models to coronary steal phenomena. Comparisons to in-vivo measurements of FFR are shown.     

CT灌注与CT血管成像对蛛网膜下腔出血后脑血管痉挛诊断价值的Meta分析

目的:采用Meta分析法比较CT脑血流灌注(computer tomography perfusion,CTP)与CT血管造影(computer tomography angiography,CTA)在蛛网膜下腔出血(subarachnoid hemorrhage,SAH)后脑血管痉挛(cerebral vasospasm,CVS)的诊断价值。方法:以Sino Med、中国期刊网、维普数据库等为国内文献的主要来源;Cochrane图书馆、Medline数据库及Ovid数据库、Elsevier和Springer数据库等作为国外文献的主要来源。发表年限为1999年至2014年。按照Cochran协作网推荐的诊断试验纳入标准选取文献,并提取纳入研究的诊断信息。统计分析采用Rev Man 5.0软件,并同时考察纳入文献间的异质性,再根据异质性结果选择相应的效应模型。对所纳入的研究予以加权定量合并,得出合并效应量,计算其95%可信区间,并对合并效应量进行假设检验。结果:按照纳入标准共获取文献6篇,其中有关CTP的3篇(多层螺旋CT),CTA为4篇,均有金标准DSA比较;前瞻性研究2篇,回顾性研究4篇。各组研究均不存在异质性,按照固定效应模型对纳入文献行汇总分析。结果显示,对于蛛网膜出血后脑血管痉挛、CTP诊断的合并效应量估计值为1.59,95%可信区间为0.94-2.69;CTA合并效应量估计值为1.45,95%可信区间为1.18-1.77。结论:对于蛛网膜下腔出血后脑血管痉挛,CTP诊断的准确性高于CTA诊断。     

Three-dimensional rotational angiography in children with an aortic coarctation

Background

Children with aortic coarctations (CoA) are increasingly percutaneously treated. Good visualisation of the CoA is mandatory and can be obtained with three-dimensional rotational angiography (3DRA). This study aims to compare the diagnostic and therapeutic additional value of 3DRA with conventional biplane angiography (CA) in children with a CoA.

Methods

Patients undergoing percutaneous treatment of CoA with balloon angioplasty (BA) or stent between 2003 and 2015, were retrospectively reviewed on success rate, complications, radiation and technical settings. Diagnostic quality of CA and 3DRA and additional value of 3DRA were scored.

Results

In total, 134 patients underwent 183 catheterisations, 121 CA and 62 3DRA-guided. Median age was 0.52 years in the BA group and 11.19 years in the stent group. 3DRA was superior to CA in displaying the left ventricle (p = 0.008), ascending aorta (p < 0.001), aortic arch (p = 0.005) and coronary arteries (p < 0.001). In the BA group, 3DRA had a significantly higher success rate than CA (100.0?% versus 68.9?%, p = 0.016). All stent interventions were successful. Complication rates did not differ significantly. The median total dose area product did not significantly differ between CA and 3DRA in the BA (27.88 μGym²/kg versus 15.81 μGym²/kg, p = 0.275) or stent group (37.34 μGym²/kg versus 45.24 μGym²/kg, p = 0.090). 3DRA was of additional value in 96.8?% of the interventions.

Conclusions

3DRA is superior to CA in diagnostic quality and not associated with increased radiation exposure. It provides high additional value in guiding CoA related interventions.

     

Plasma oxysterols and angiographically determined coronary atherosclerosis: a case control study

Several in vitro and in vivo experiments have implicated oxysterols in the aetiology and progression of atherosclerosis. Oxysterols may be formed endogenously by oxidation of cholesterol and thus may form a marker of LDL oxidation. They may also be obtained exogenously through dietary intake. We investigated the association of oxysterols with the degree of coronary stenosis in patients undergoing coronary angiography. Cases with severe coronary atherosclerosis 80 stenosis in one of the major coronary vessels, n =80 were compared with controls with no or minor stenosis 50 stenosis in all three major coronary vessels, n =79 . Cases and controls were prestratified on age, gender and smoking habits. Evaluated were plasma levels of unesterified 7 hydroxycholesterol, 7 hydroxycholesterol, 25 hydroxycholesterol, 7 ketocholesterol, cholestane triol and 5,6 epoxycholestanol. 7 Hydroxycholesterol made up 67 of the total amount of plasma oxysterol concentration and was the only one significantly higher in cases 1.53 mu g per 100 ml vs 1.27 mu g per 100 ml, p 0.05 . Further, cases had somewhat higher LDL cholesterol levels and significantly lower HDL cholesterol levels than controls. After multivariate adjustment to account for this difference in lipid levels and for the prestratification factors the mean difference between cases and controls for 7 hydroxycholesterol 0.14 mu g per 100 ml was no longer significant. Also the other oxysterols showed no significant association with the degree of coronary stenosis. Multiple logistic regression analyses showed an adjusted odds ratio of 1.07 95 CI, 0.45-2.59 in the highest tertile of total plasma oxysterol level. We conclude, that this study does not support the hypothesis that plasma oxysterols form an additional risk factor for coronary atherosclerosis.     

肺动脉栓塞的64层螺旋CT血管成像技术分析

目的从技术上探讨64层螺旋CT肺动脉造影对肺栓塞的诊断的价值。方法对62例临床疑诊肺栓塞的患者行64排螺旋CT肺动脉造影检查,采用最大密度投影(MIP)、多平面重建(MPR)、曲面重建(CPR)、容积漫游(VR)及仿真内窥镜等后处理技术,分析所获得的相关CT资料。结果64排多层螺旋CT肺动脉造影可较准确、清晰、全面地显示24例累及肺动脉及其分支共152处栓子的位置、形态、范围和程度。结论64排多层螺旋CT肺动脉造影是肺栓塞及时准确无创的诊断方法,是临床诊断肺栓塞的首选筛查办法,对肺动脉栓塞的诊断具有明显的技术优势。     

64层螺旋CT冠状动脉造影的护理

多层螺旋凹冠脉造影与导管法冠脉造影相比,具有无创、安全、经济快捷等优点,在临床上应用日见广泛。但影响其成像质量的因素较多,而检查前、检查中及检查后的护理是其很重要的环节,本文就与该项检查有关的护理问题进行探讨,提出相应的护理对策。     

Plasma annexin A5 level relates inversely to the severity of coronary stenosis

Exogenous radiolabeled annexin A5 is taken up by atherosclerotic tissue. We measured endogenous plasma annexin A5 and circulating oxidized low-density lipoprotein (oxLDL), a biochemical marker of atherosclerosis, in men with either severe angiographically determined coronary stenosis (n = 90) or no or only minor stenosis (n = 96). Men without history of cardiac disease or treatment and free of plaques in the carotid artery (by ultrasonography) were taken as controls (n = 87). Opposite to oxLDL, annexin A5 decreased at increasing severity of stenosis. OxLDL was lowest and annexin A5 was highest in controls. Percentage differences between groups were higher for annexin A5 than for oxLDL, and highest for oxLDL/annexin A5 ratio. The oxLDL/annexin A5 ratio is a better marker of the severity of coronary stenosis than oxLDL alone, may reflect the presence and extent of the atherosclerotic cardiovascular disease, and might prove useful for preclinical screening purposes.     

Evaluation of global left ventricular function assessment of non-fluorescent electromechanical endocardial mapping compared with biplane left ventricular contrast angiography

Background. Little is known about the diagnostic accuracy of global LV function assessment by electromechanical endocardial mapping (EEM). The aim of the present study was to determine the relationship between global left ventricular (LV) function measured by EEM and biplane left ventricular contrast angiography (LVA) after ST-elevation myocardial infarction (STEMI). Methods. Thirty-seven patients underwent LVA and EEM during routine coronary angiography four months after primary percutaneous intervention for STEMI. Global LV function parameters were available from both techniques in all patients. LVA was regarded as reference standard. Results. All procedures were carried out without adverse events. Average age was 55±10 years and 84% were male. EEM showed an overestimation of end-diastolic volume (EDV) and end-systolic volume (ESV) of 6.5 ml and 25.5 ml, respectively. Correlation (r) was 0.84 (p<0.001) for EDV and 0.74 (p<0.001) for ESV. Average left ventricular ejection fraction (LVEF) measured by EEM was 17.2% point (±11.3% point) lower compared with LVA (r=0.69, p<0.001). Conclusion. Although global functional parameters by EEM correlated well with LVA, the relatively large differences in terms of absolute values for ventricular volumes and LVEF render the two techniques non-interchangeable for global LV-function-data. (Neth Heart J 2010;18:72–77.)