Validation of coronary artery saphenous vein bypass graft diameter measurements using quantitative angiography

The accepted value for reproducibility (true change) is two standard deviations (SD) of the differences between repeat measurements. It has been well established for coronary artery measurements using several different quantitative coronary angiography (QCA) systems, but it has not been well documented for saphenous vein grafts (SVG). The purpose of this study was to assess, using the Cardiovascular Measurement System (CMS), the measurement reproducibility of 24 vein grafts from 24 patients who had symptom-directed control angiography. Three equal graft segments were studied separately. Focal narrowings expressed in percent stenosis varied from 5 to 80% (mean 20.8±15.9%). The average minimum lumen diameter (MLD) was 3.07±0.81 mm and the average interpolated reference diameter (Ref.D) was 3.87±0.58 mm. We assessed the reproducibility of measurements obtained from two separate imagings of the graft in the same view but at least 20 minutes apart, near the beginning and at the end of the angiographic procedure (simulating baseline and end-trial examinations). The SD for differences in measurements (variability) was 0.183 mm for the MLD, 0.193 mm for the Ref.D, 0.184 mm for the mean diameter (Mean D) and 3.72% for the percent diameter stenosis (PDS). A reasonable true change cut-off for SVG measurements in our laboratory is ≥ 0.4 mm for the minimum and mean lumen diameters, and ≥ 10% for the PDS, when QCA is obtained with the QCA-CMS analytical software package.     

Non-invasive assessment of atherosclerotic coronary lesion length using multidetector computed tomography angiography: comparison to quantitative coronary angiography

Multidetector computed tomography angiography (CTA) provides information on plaque extent and stenosis in the coronary wall. More accurate lesion assessment may be feasible with CTA as compared to invasive coronary angiography (ICA). Accordingly, lesion length assessment was compared between ICA and CTA in patients referred for CTA who underwent subsequent percutaneous coronary intervention (PCI). 89 patients clinically referred for CTA were subsequently referred for ICA and PCI. On CTA, lesion length was measured from the proximal to the distal shoulder of the plaque. Quantitative coronary angiography (QCA) was performed to analyze lesion length. Stent length was recorded for each lesion. In total, 119 lesions were retrospectively identified. Mean lesion length on CTA was 21.4 ± 8.4 mm and on QCA 12.6 ± 6.1 mm. Mean stent length deployed was 17.4 ± 5.3 mm. Lesion length on CTA was significantly longer than on QCA (difference 8.8 ± 6.7 mm, P < 0.001). Moreover, lesion length visualized on CTA was also significantly longer than mean stent length (CTA lesion length-stent length was 4.2 ± 8.7 mm, P < 0.001). Lesion length assessed by CTA is longer than that assessed by ICA. Possibly, CTA provides more accurate lesion length assessment than ICA and may facilitate improved guidance of percutaneous treatment of coronary lesions.     

Validation of a new contrast material protocol adapted to body surface area for optimized low-dose CT coronary angiography with prospective ECG-triggering

In patients with large total blood volume contrast material (CM) dilution decreases coronary attenuation in CT coronary angiography (CTCA). As increased blood volume is well paralleled by body surface area (BSA) we assessed a BSA-adapted CM protocol to compensate for dilution effects. Low-dose CTCA with prospective ECG-triggering was performed in 80 patients with a BSA-adapted CM bolus ranging 40–105 ml and injection rate ranging 3.5–5.0 ml/s for a BSA of <1.70 to ≥2.5 m². Eighty control patients matched for BSA who had previously undergone routine CTCA with a fixed CM protocol of 80 ml at 5 ml/s served as reference group. The average vessel attenuation from the proximal right (RCA) and the left main coronary artery (LMA) was assessed. Correlation of BSA with vessel attenuation was assessed in both groups. BSA-matching of all patients was successful (BSA-adapted group 1.98 ± 0.15 m², range 1.66–2.39 m² versus reference group 1.98 ± 0.17 m², range 1.59–2.38 m²; P = 0.74). Mean CM bolus was significantly smaller in the BSA-adapted versus the reference group (70.9 ± 14.1 vs. 80.0 ± 0 ml, P < 0.001). There was no correlation in the BSA-adapted group (r = ?0.07, P = 0.53, SEE = 0.15), while coronary attenuation was inversely related to BSA in the reference group (r = ?0.59, P < 0.001, SEE = 0.14). We have successfully validated a BSA-adapted contrast material protocol which results in a comparable coronary contrast enhancement independent of individual BSA. This was achieved despite a significant reduction in the overall contrast material amount.     

Complementary use of CT angiography and stress tests to evaluate coronary heart disease

Reliance on any single method of investigation as a gold standard to evaluate coronary disease is no longer appropriate or sufficient. Due consideration of the disease’s complex pathomechanisms and heterogeneous symptoms entails optimized risk stratification and further clinical treatment decisions based on comprehensive knowledge of heart morphology and function. We review the latest advances in combining different CT techniques with stress/rest myocardial perfusion imaging using single photon emission CT or positron emission tomography. Particular emphasis is placed on the advantages of three-dimensional image fusion techniques, which can accurately allocate perfusion defects to the supplying coronary artery. This noninvasive cross-modal imaging method is unsurpassed for identifying the location, extent, and hemodynamic relevance of coronary artery disease, which are the key elements required for rational decisions to perform either interventional therapy or proceed with medical treatment.     

Rapid quantitative analysis of phospholipid erythrocytes by densitometric thin-layer chromatography.

A copper acetate spray reagent, a Silgur-25 plate composed of a layer combined Kieselguhr/Silica gel, and a "flying-spot" densitometer Vitration TLD 100 have been used for the quantitative densitometric thin-layer chromatography of principal phospholipids from human red cells. This procedure can give information quickly about the red cell abnormalities associated with modification of phospholipid metabolism.     

Variability of quantitative coronary angiography: an evaluation of on-site versus core laboratory analysis

To assess the validity of locally performed off-line quantitative coronary angiography (QCA) measurement in clinical trials, we carried out a comparative study between on-site QCA analysis and analysis performed at an independent external core laboratory. One local operator analyzed the pre, post and follow-up angiograms of 116 patients participating in the Stenting in Small Coronary Arteries Study (SISCA) prior to final QCA analysis in the core laboratory. The mean values of the reference diameter (RD), minimal lumen diameter (MLD) and diameter stenosis (DS) showed acceptable agreement between study site and core laboratory. However, on the level of individuals the interobserver differences were large, affecting the outcome of restenosis rate significantly, and in a such way that the conclusions in the SISCA trial might have come out differently if a core laboratory had not been used. This emphasizes the importance of using independent core laboratories in coronary interventional trials.     

冠状动脉造影成像与64排螺旋CT冠状动脉成像定性定量分析动脉粥样硬化的应用比较

目的:64排螺旋CT冠状动脉成像与冠状动脉造影结果对比分析,评估冠状动脉病变的临床意义及二者的符合率。方法:选取2005-05/2006-07在解放军总医院疑似或确诊冠状动脉粥样硬化性心脏病患者行64排螺旋CT冠状动脉成像检查患者共85例,男64例,女21例;年龄41～83岁,平均61岁。85例患者均在64排螺旋CT检查后行冠状动脉造影。患者知情同意参加本实验。冠状动脉狭窄的测定:64排螺旋CT借助血管分析软件,直接提供"直径法"和"面积法"的狭窄率数值。冠状动脉造影检查按冠状动脉管腔直径分为正常;25%～49%为轻度狭窄;50%～74%为轻到中度狭窄;75%～94%为中到重度狭窄,95%～99%为重度狭窄,100%狭窄为闭塞。结果:64排螺旋CT冠状动脉成像显示冠状动脉狭窄(均以≥50%有临床意义)与冠状动脉造影的符合率在左冠状动脉主干(左主干)为89%,左冠状动脉前降支(前降支)为93%,左冠状动脉回旋支(回旋支)为68%,右冠状动脉为48%。结论:64排螺旋CT冠状动脉成像能较准确反应各支血管部位的狭窄程度,对左主干及前降支病变与冠状动脉造影检查符合率较高,在评价冠状动脉狭窄、定性和定量检测冠状动脉粥样硬化斑块等方面都有良好的临床应用价值。     

Volume coronary angiography using targeted scans (VCATS): a new strategy in MR coronary angiography

The aim of this study was to explore the clinical possibilities of a new strategy for magnetic resonance imaging of the coronary arteries. Thirteen patients were studied by volume coronary angiography using targeted scans (VCATS) to visualize the major coronary arteries in a series of breath-holds. The proximal coronary arteries were clearly seen in 92% and the mid segments in 50–70% of the patients. VCATS was able to visualize a total vessel length of the left main (LM) (mean: 9.4 ± 3.4 mm), of the left anterior descending (LAD) 69 ± 20 mm, of the right coronary artery (RCA) 90 ± 33 mm and of the left circumflex (LCX) 41 ± 18 mm. There was a reasonable correlation between the VCATS and conventional coronary angiography (CAG) for vessel diameter (r = 0.71), with a slight overestimation of 0.7 mm by VCATS. There were nine significant stenoses present of which six were correctly detected, three were missed and one false positive was present. VCATS is fast strategy for visualizing the major coronary artery branches and has the potential to detect significant stenoses in these branches.     

Reproducibility of quantitative coronary analysis

Because of limited storage capacity for digital images, angiographic laboratories without cinefilm are dependent on locally performed quantitative coronary angiography (QCA) in clinical studies. In the present study the intra-and interobserver variability, as well as variability between different laboratories and variability due to frame selection was analyzed. A total of 20 coronary lesions were studied in two different digital laboratories 12±8 days apart. Images were analyzed on-line and after being transferred to a Cardiac Work Station (CWS). There was no significant difference between the measurement situations. For minimal luminal diameter (MLD) precision (SD of signed errors) ranged from 0.12 mm to 0.20 mm, for reference diameter (RD) from 0.15 mm to 0.28 mm, and for percent diameter stenosis (DS) from 4.2% to 5.8%. Overall relative precision was obtained by normalizing the QCA parameters, and was 11.9% for MLD, 7.0% for RD and 8.5% for DS (p<0.001, RD and DS compared to MLD). The overall variability in the interobserver and in the interlaboratory comparisons was 11.2% and 10.4%, respectively (n.s.) (n.s.). Thus the variability of QCA performed in cinefilmless, digital laboratories is small, and within a range making it an useful tool for clinical practice and group comparisons in clinical studies. However, the error range of QCA measurements must be taken into consideration when judging results from individual patients.     

Determination of optimal viewing regions for X-ray coronary angiography based on a quantitative analysis of 3D reconstructed models

Current expert-recommended views for coronary angiography are based on heuristic experience and have not been scientifically studied. We sought to identify optimal viewing regions for first and second order vessel segments of the coronary arteries that provide optimal diagnostic value in terms of minimizing vessel foreshortening and overlap. Using orthogonal 2D images of the coronary tree, 3D models were created from which patient-specific optimal view maps (OVM) allowing quantitative assessment of vessel foreshortening and overlap were generated. Using a novel methodology that averages 3D-based optimal projection geometries, a universal OVM was created for each individual coronary vessel segment that minimized both vessel foreshortening and overlap. A universal OVM model for each coronary segment was generated based on data from 137 patients undergoing coronary angiography. We identified viewing regions for each vessel segment achieving a mean vessel foreshortening value of 5.8 ± 3.9% for the left coronary artery (LCA) and 5.6 ± 3.6% for the right coronary artery (RCA). The overall mean overlap values achieved were 8.7 ± 7.9% for the LCA and 4.6 ± 3.2% for the RCA. This scientifically-based OVM evaluation of coronary vessel segments provides the means to facilitate acquisitions during coronary angiography and interventions that minimize imaging inaccuracies related to foreshortening and overlap, improving the accuracy, efficiency, and safety of diagnostic and interventional coronary procedures.     

Validation of quantitative analysis of intravascular ultrasound images

This study investigated the accuracy and reproducibility of a computer-aided method for quantification of intravascular ultrasound. The computer analysis system was developed on an IBM compatible PC/AT equipped with a framegrabber. The quantitative assessment of lumen area, lesion area and percent area obstruction was performed by tracing the boundaries of the free lumen and original lumen. Accuracy of the analysis system was tested in a phantom study. Echographic measurements of lumen and lesion area derived from 16 arterial specimens were compared with data obtained by histology. The differences in lesion area measurements between histology and ultrasound were minimal (mean ± SD: ?0.27±1.79 mm², p>0.05). Lumen area measurements from histology were significantly smaller than those with ultrasound due to mechanical deformation of histologic specimens (?5.38±5.09 mm², p<0.05). For comparison with angiography, 18 ultrasound cross-sections were obtainedin vivo from 8 healthy peripheral arteries. Luminal areas obtained by angiography were similar to those by ultrasound (?0.52±5.15 mm², p>0.05). Finally, intra- and interobserver variability of our quantitative method was evaluated in measurements of 100in vivo ultrasound images. The results showed that variations in lumen area measurements were low (5%) whereas variations in lesion area and percent area obstruction were relatively high (13%, 10%, respectively). Results of this study indicate that our quantitative method provides accurate and reproducible measurements of lumen and lesion area. Thus, intravascular ultrasound can be used for clinical investigation, including assessment of vascular stenosis and evaluation of therapeutic intervention.     

CT coronary angiography of chronic total occlusions of the coronary arteries: how to recognize and evaluate and usefulness for planning percutaneous coronary interventions

Purpose This investigation sought to determine which newly available asynchrony parameter derived from gated myocardial perfusion SPECT (GMPS) systolic wall thickening data best distinguishes patients with left bundle branch block (LBBB) from normal subjects. Methods and materials Emory Cardiac Toolbox (ECTb) algorithms were used to compute left ventricular (LV) global and regional function and perfusion indices with regional contraction phases for 20 patients with LBBB, and in 9 control (CTL) subjects who had no function or perfusion abnormalities. Histogram plots of phase frequencies versus R–R interval times included phase standard deviation (SD), bandwidth (BW), skewness and kurtosis. Z-score asynchrony measures were derived for phases sampled using the conventional 17-segment model. Results In CTLs contraction occurred nearly simultaneously in all segments, while LBBBs exhibited a wide variety of heterogeneous contraction patterns. Global parameters that differed between LBBBs versus CTLs included EF, end-systolic volume and end-diastolic volume, and asynchrony measures that were different included BW, phase SD and z-scores. Z-scores most strongly discriminated LBBBs from CTLs (93% of cases correctly predicted, logistic regression χ² = 29.7, P < 0.0001). Z-scores, phase SD and lateral–septal wall timing were highly reproducible (r = 0.99, 0.99 and r = 0.87, respectively), with no significant inter-observer differences. Conclusion While traditional global function parameters were different in LBBBs and CTLs, asynchrony parameters characterized LBBB most strongly.     

Incremental value of dual-energy CT to coronary CT angiography for the detection of significant coronary stenosis: comparison with quantitative coronary angiography and single photon emission computed tomography

To determine the value of dual-energy CT (DECT) and combined information of perfusion and angiography in diagnosing coronary artery disease (CAD), with single photon emission computed tomography (SPECT) and quantitative coronary angiography (QCA) as a reference standard. Thirty-four patients were enrolled in this study. DECT was used as a contrast-enhanced retrospectively ECG-gated scan protocol during the rest state and tubes were set at 140/100 kV. DECT angiography (DE-CTA) and DECT perfusion (DE-CTP) were calculated from two kV images. DE-CTP results were compared with SPECT and DE-CTA with QCA, respectively. The combined DE-CTP with DE-CTA data were compared to QCA in diagnosis of obstructive CAD (stenosis ≥ 50%). DECT showed diagnostic image quality in 31 patients. Using SPECT as a reference, DE-CTP had sensitivity of 68%, specificity of 93%, and sensitivity of 81%, and specificity of 92% for identifying any type of perfusion deficits on the segment- and territory-based analysis, respectively. Using QCA as a reference standard, DE-CTA showed sensitivity of 82%, specificity of 91% and accuracy of 86% for detecting ≥50% coronary stenosis on the vessel-based analysis, whereas the combination of DE-CTA and DE-CTP gave sensitivity of 90%, specificity of 86% and accuracy of 88% for detecting ≥50% coronary stenosis, respectively. Combination of DE-CTP and DE-CTA may improve diagnostic performance compared to CTA alone for the diagnosis of significant coronary stenosis.     

Towards quantitative analysis of coronary CTA

The current high spatial and temporal resolution, multi-slice imaging capability, and ECG-gated reconstruction of multi-slice computed tomography (MSCT) allows the non-invasive 3D imaging of opacified coronary arteries. MSCT coronary angiography studies are currently carried out by the visual inspection of the degree of stenosis and it has been shown that the assessment with sensitivities and specificities of 90% and higher can be achieved. To increase the reproducibility of the analysis, we present a method that performs the quantitative analysis of coronary artery diseases with limited user interaction: only the positioning of one or two seed points is required. The method allows the segmentation of the entire left or right coronary tree by the positioning of a single seed point, and an extensive evaluation of a particular vessel segment by placing a proximal and distal seed point. The presented method consists of: (1) the segmentation of the coronary vessels, (2) the extraction of the vessel centerline, (3) the reformatting of the image volume, (4) a combination of longitudinal and transversal contour detection, and (5) the quantification of vessel morphological parameters. The method is illustrated in this paper by the segmentation of the left and right coronary trees and by the analysis of a coronary artery segment. The sensitivity of the positioning of the seed points is studied by varying the position of the proximal and distal seed points with a standard deviation of 6 and 8 mm (along the vessels course) respectively. It is shown that only close to the individual seed points the vessel centerlines deviate and that for more than 80% of the centerlines the paths coincide. Since the quantification depends on the determination of the centerline, no user variability is expected as long as the seed points are positioned reasonably far away from the vessel lesion. The major bottleneck of MSCT imaging of the coronary arteries is the potential lack of image quality due to limitations in the spatial and temporal resolution, irregular or high heart beat, respiratory effects, and variations of the distribution of the contrast agent: the number of rejected vessel segments in diagnostic studies is currently still too high for implementation in routine clinical practice. Also for the automated quantitative analysis of the coronary arteries high image quality is required. However, based upon the trend in technological development of MSCT scanners, there is no doubt that the quantitative analysis of MSCT coronary angiography will benefit from these technological advances in the near future.     

A new look at coronary angiograms: plaque morphology as a help to diagnosis and to evaluate outcome

Characterization of plaque morphology can provide useful information beyond those generally yielded by the more traditional methods of interpretation of coronary angiograms based on assessment of severity of stenoses and number of diseased vessels. Focus on the culprit coronary lesion in acute myocardial infarction and in unstable angina allows recognition of the complex plaque and of presence of endoluminal thrombi that are closely associated to the mechanisms of the disease. Response to treatment in these clinical situations, and the healing process can be assessed by repeated opacifications of the lesion. The presence of a residual thrombus is associated with a worse clinical outcome and also a higher risk of complication if coronary angioplasty is performed. The prognostic information derived from the morphologic analysis extends to the chronic phase of the disease. The extent score of disease, defined as the sum of coronary artery segments showing a narrowing of any severity marks more severe disease and predicts future progression. Severity of stenosis is also a predictor. More severe lesions will occlude more frequently but most often without clinical consequences. Occlusion of less severe stenosis, on the other hand, leads to acute myocardial infarction or to the other manifestations of acute coronary syndromes. Other morphologic features are also associated with a higher risk of myocardial infarction. These include a geometry favoring blood flow separation and turbulence such as acute inflow and outflow angles of the stenosis and presence of a division within its vicinity. This new look at coronary angiograms may help orient therapy. Patients with angina and a significant stenosis will profit from a corrective intervention. Others with a high extent score should receive a comprehensive program for control of risk factors. Patients with a lesion of borderline significance at risk of activation should be closely monitored, and when clinical symptoms evolve, receive more intensive antithrombotic therapy. Quantification of the morphologic characteristics of the plaque, coupled to new techniques for endovascular imaging should lead in the future to better diagnostic and better risk stratification.     

Validation of a new automated irradiation system for off-line ECP

Extracorporeal photopheresis (ECP) is a cell therapy originally employed for cutaneous T cell lymphoma and later for GvHD, solid organ rejection and other immunological diseases demonstrating an excellent safety profile. Mononuclear cell (MNCs) apoptosis triggered by UV-A light irradiation in the presence of 8-methoxypsoralene has a key role in priming the cells, ultimately leading to immunomodulation. We report preliminary data about an evaluation of the new automated irradiator device LUMILIGHT (Pelham Crescent srl) for off-line ECP. Fifteen MNCs samples collected by apheresis from 15 adult patients undergoing ECP at our Center were cultured immediately after irradiation along with untreated samples and evaluated at 24, 48 and 72 h timepoints for T cell apoptosis and viability by flow cytometry with Annexin V and Propide Iodidum staining. Post irradiation Hematocrit (HCT), calculated by the device, was compared with that of the automated cell counter. Bacterial contamination was also tested. In irradiated samples after 24–48 and 72 h, the average total apoptosis was 47 %, 70 % and 82 %, respectively, showing a significant difference from untreated samples; residual viable lymphocytes at 72 h were, on average, 18 %. The greatest initiation of apoptosis occurred from 48 h of irradiation onwards. Average early apoptosis of irradiated samples decreased over time (26 %, 17 % and 10 % at 24, 48 and 72 h, respectively). HCT measured by LUMILIGHT was over-estimated, possibly due to the low pre irradiation red blood cell contamination. Bacterial tests resulted negative. Our study showed the LUMILIGHT device to be a valid instrument for MNCs irradiation with good handling and no major technical problems as well as no adverse events in the patients. Our data need to be confirmed in larger studies.     

A new strategy of high-speed screening and quantitative structure-activity relationship analysis to evaluate human ATP-binding cassette transporter ABCG2-drug interactions

The human ATP-binding cassette (ABC) transporter ABCG2 (BCRP/MXR1/ABCP) plays a critical role in cellular protection against xenobiotics as well as pharmacokinetics of drugs in our body. In the present study, we aimed to analyze the quantitative structure-activity relationship (QSAR) latently residing in ABCG2-drug interactions. We first established standard methods for expression of human ABCG2 in insect cells, quality control of plasma membrane samples by using electron microscopy techniques, and high-speed screening of ABCG2 inhibition with test compounds. Plasma membrane vesicles prepared from ABCG2-expressing Sf9 cells were used as a model system to measure the ATP-dependent transport of [3H]methotrexate (MTX). Forty-nine different therapeutic drugs and natural compounds were tested for their ability to inhibit ABCG2-mediated MTX transport. Based on their inhibition profiles, we performed QSAR analysis using chemical fragmentation codes deduced from the structures of test compounds. Multiple linear regression analysis delineated a relationship between the structural components and the extent of ABCG2 inhibition, allowing us to identify one set of structure-specific chemical fragmentation codes that are closely correlated with the inhibition of ABCG2 transport activity. Based on the QSAR analysis data, we predicted the potency of gefitinib to inhibit ABCG2. The validity of our QSAR-based prediction for gefitinib was examined by actual experiments. Our kinetic analysis experiments suggest that the ABCG2-ATP complex binds gefitinib. The present study provides a new strategy for analyzing ABCG2-drug interactions. This strategy is considered to be practical and useful for the molecular designing of new ABCG2 modulators.     

Assessment of three dimensional quantitative coronary analysis by using rotational angiography for measurement of vessel length and diameter

The aim of the study was to assess the accuracy of the three-dimensional (3D) quantitative coronary analysis (QCA) system by comparing with that of intravascular ultrasound (IVUS) QCA and two-dimensional (2D) QCA. 3D QCA, 2D QCA and IVUS QCA were performed in 45 vessel segments. The obtained values for the branch to branch segment vessel length and the proximal part of the segment vessel's lumen diameter were measured. Inter-technique agreement was analyzed using paired sample t-test and Bland-Altman analysis. No differences were found in vessel lengths taken by 3D QCA and IVUS QCA (mean difference: 0.29?±?1.06?mm, P?=?0.07). When compared with IVUS QCA, 2D QCA underestimated vessel length (mean difference: -1.78?±?2.55, P?相似文献