Relevant Coronary Artery Stenosis Research Articles

Epicardial fat volume is associated with primary coronary slow-flow phenomenon in patients with severe aortic stenosis undergoing transcatheter valve implantation

BackgroundPrimary coronary slow flow (CSF) is defined as delayed opacification of the distal epicardial vasculature during coronary angiography in the absence of relevant coronary artery stenoses. Microvascular disease is thought to be the underlying cause of this pathology. Epicardial fat tissue (EFT) is an active endocrine organ directly surrounding the coronary arteries that provides pro-inflammatory factors to the adjacent tissue by paracrine and vasocrine mechanisms. The aim of the present study was to investigate a potential association between EFT and primary CSF and whether EFT can predict the presence of primary CSF.MethodsBetween 2016 and 2017, n = 88 patients with high-grade aortic stenosis who were planned for transcatheter aortic valve implantation (TAVI) were included in this retrospective study. EFT volume was measured by pre-TAVI computed tomography (CT) using dedicated software. The presence of primary CSF was defined based on the TIMI frame count from the pre-TAVI coronary angiograms.ResultsThirty-nine of 88 TAVI patients had CSF (44.3%). EFT volume was markedly higher in patients with CSF (142 ml [IQR 107–180] vs. 113 ml [IQR 89–147]; p = 0.009) and was strongly associated with the presence of CSF (OR 1.012 [95%CI 1.002–1.021]; p = 0.014). After adjustment, EFT volume was still an independent predictor of CSF (OR 1.016 [95%CI 1.004–1.026]; p = 0.009).ConclusionPrimary CSF was independently associated with increased EFT volume. Further studies are needed to validate this finding and elucidate whether a causal relationship exists.

Intracoronary ECG ST-segment shift remission time during reactive coronary hyperemia (tau-icECG): a new approach to assess hemodynamic coronary stenosis severity

Abstract Background Coronary pressure-derived fractional flow reserve (FFR) measurements are recommended for hemodynamic coronary stenosis assessment. Given temporary paralysis of the coronary microcirculation during hyperemia, pressure is, in theory, directly related to coronary flow. Pressure drop during hyperemia across a coronary stenosis, thus, provides an estimate of its restrictive effect on flow. FFR during reactive hyperemia induced by a proximal, 1-minute coronary artery balloon occlusion has been shown non-inferior to FFR as obtained by adenosine-induced hyperemia. Intracoronary ECG (icECG) is more sensitive in detecting myocardial ischemia than the surface ECG, and can be easily obtained. Purpose The present study evaluated a novel diagnostic approach based on icECG ST-segment shift remission time for hemodynamic stenosis severity assessment. Methods This was a retrospective observational trial in patients with chronic coronary syndrome, who underwent hemodynamic measurements during a brief coronary occlusion with simultaneous icECG recording during coronary angiography. The icECG recording was used for a beat-to-beat analysis of the ST-segment elevation performed by a previously developed fully autonomous algorithm. The time after release of the 1-minute ostial coronary balloon occlusion when the ST elevation reached 50% of the pre-occlusion (baseline) isoelectric line, i.e., icECG remission half time (τ-icECG; τ=tau), was obtained by the algorithm (Figure1). τ-icECG was evaluated using the simultaneously obtained FFR at a threshold of 0.80 as reference parameter. Results 139 icECGs from 119 patients were analysed, 23 had to be excluded in advance, due to incomplete icECG recording or algorithm failure. A ROC-analysis of τ at a threshold of >8s found it significantly accurate for detecting a hemodynamically relevant coronary stenosis at FFR≤0.80 (area under the ROC-curve 0.618, 95% CI 0.507-0.735, sensitivity 60%, specificity 67%, p=0.037) (Figure2). Conclusion Τ-icECG, a measure of icECG ST-elevation remission time to isoelectricity as obtained during reactive hyperemia FFR accurately detects hemodynamically relevant coronary artery stenoses at a threshold of ≥ 8 seconds.

Stress Cardiovascular Magnetic Resonance Imaging for the Detection of Coronary Artery Disease.

Stress cardiovascular magnetic resonance (CMR) imaging has received extensive validation for the assessment of ischemic heart disease. Without ionizing radiation exposure, it offers in-depth information regarding cardiac structure and function, presence and degree of myocardial ischemia and myocardial viability. When compared to other imaging modalities, it has demonstrated excellent sensitivity and specificity in detecting functionally relevant coronary artery stenosis, as well as strong prognostic value in clinical risk stratification. The current scientific data support a greater expansion of stress CMR. This review investigates the current stress CMR techniques and protocols, as well as its relevance in diagnosis and prognosis of coronary artery disease.

Radiomics in Cardiac Computed Tomography.

In recent years, there has been an increasing recognition of coronary computed tomographic angiography (CCTA) and gated non-contrast cardiac CT in the workup of coronary artery disease in patients with low and intermediate pretest probability, through the readjustment guidelines by medical societies. However, in routine clinical practice, these CT data sets are usually evaluated dominantly regarding relevant coronary artery stenosis and calcification. The implementation of radiomics analysis, which provides visually elusive quantitative information from digital images, has the potential to open a new era for cardiac CT that goes far beyond mere stenosis or calcification grade estimation. This review offers an overview of the results obtained from radiomics analyses in cardiac CT, including the evaluation of coronary plaques, pericoronary adipose tissue, and the myocardium itself. It also highlights the advantages and disadvantages of use in routine clinical practice.

Stable patients with suspected myocardial ischemia: comparison of machine-learning computed tomography-based fractional flow reserve and stress perfusion cardiovascular magnetic resonance imaging to detect myocardial ischemia

BackgroundMachine-Learning Computed Tomography-Based Fractional Flow Reserve (CT-FFRML) is a novel tool for the assessment of hemodynamic relevance of coronary artery stenoses. We examined the diagnostic performance of CT-FFRML compared to stress perfusion cardiovascular magnetic resonance (CMR) and tested if there is an additional value of CT-FFRML over coronary computed tomography angiography (cCTA).MethodsOur retrospective analysis included 269 vessels in 141 patients (mean age 67 ± 9 years, 78% males) who underwent clinically indicated cCTA and subsequent stress perfusion CMR within a period of 2 months. CT-FFRML values were calculated from standard cCTA.ResultsCT-FFRML revealed no hemodynamic significance in 79% of the patients having ≥ 50% stenosis in cCTA. Chi2 values for the statistical relationship between CT-FFRML and stress perfusion CMR was significant (p < 0.0001). CT-FFRML and cCTA (≥ 70% stenosis) provided a per patient sensitivity of 88% (95%CI 64–99%) and 59% (95%CI 33–82%); specificity of 90% (95%CI 84–95%) and 85% (95%CI 78–91%); positive predictive value of 56% (95%CI 42–69%) and 36% (95%CI 24–50%); negative predictive value of 98% (95%CI 94–100%) and 94% (95%CI 90–96%); accuracy of 90% (95%CI 84–94%) and 82% (95%CI 75–88%) when compared to stress perfusion CMR. The accuracy of cCTA (≥ 50% stenosis) was 19% (95%CI 13–27%). The AUCs were 0.89 for CT-FFRML and 0.74 for cCTA (≥ 70% stenosis) and therefore significantly different (p < 0.05).ConclusionCT-FFRML compared to stress perfusion CMR as the reference standard shows high diagnostic power in the identification of patients with hemodynamically significant coronary artery stenosis. This could support the role of cCTA as gatekeeper for further downstream testing and may reduce the number of patients undergoing unnecessary invasive workup.

Identification of hemodynamically significant coronary artery disease with stress myocardial blood flow ratio by dynamic CT perfusion studies

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Coronary computed tomographic angiography (CTA) is an accepted noninvasive tool with high diagnostic accuracy for the evaluation of coronary artery disease (CAD). However, coronary CTA is limited in that it does not provide information on the hemodynamic relevance of coronary artery stenosis. Therefore, to determine the potential benefit of future coronary revascularization, a functional assessment is often required. A protocol combining coronary computed tomographic angiography (CTA) and CTP can provide a simultaneous assessment of both coronary artery ischemia and anatomy. Purpose This study sought to evaluate the diagnostic accuracy of stress myocardial blood flow ratio (SFR), a novel parameter derived from stress dynamic computed tomographic perfusion (CTP), for the detection of hemodynamically significant coronary stenosis. Methods A total of 98 patients (mean age 54.5 ± 10 years) with 128 vessels with either 1- or 2-vessel disease, scheduled for invasive angiography were included in this study. Stress dynamic CTP was performed followed by coronary CTA using a dual-source computed tomographic system. Fractional flow reserve was performed at subsequent invasive angiography to identify hemodynamically significant stenosis. Stress myocardial blood flow ratio (SFR) was defined as the ratio of hyperemic myocardial blood flow (MBF) in an artery with stenosis to hyperemic MBF in a non-diseased artery. The diagnostic accuracy of the SFR index was determined against the reference standard of invasive fractional flow reserve ≤0.80. Results 58 (45.3%) vessels were deemed hemodynamically significant by fractional flow reserve (FFR) measurement. Hyperemic MBF and SFR were lower for vessels with hemodynamically significant lesions (95 ± 32.2 ml/100 ml/min vs. 140.5 ± 30.4 ml/100 ml/min; p &amp;lt; 0.01 for both). When compared with ≥50% stenosis by CTA, the specificity for detecting ischemia by SFR increased from 44% to 92%, while the sensitivity decreased from 93% to 58%. The combination of stenosis ≥50% by CTA and SFR resulted in an area under the curve of 0.9, which was significantly higher compared with hyperemic MBF, area under the curve = 0.79 and p &amp;lt; 0.01. Conclusion Our study concludes that the calculation of SFR by dynamic CTP provides a pioneering and accurate method to identify flow-limiting coronary stenosis. Abstract Figure.

Influence of diabetes mellitus on the diagnostic performance of machine learning-based coronary CT angiography-derived fractional flow reserve: a multicenter study.

To examine the diagnostic accuracy of machine learning-based coronary CT angiography-derived fractional flow reserve (FFRCT) in diabetes mellitus (DM) patients. In total, 484 patients with suspected or known coronary artery disease from 11 Chinese medical centers were retrospectively analyzed. All patients underwent CCTA, FFRCT, and invasive FFR. The patients were further grouped into mild (25~49 %), moderate (50~69 %), and severe (≥ 70 %) according to CCTA stenosis degree and Agatston score < 400 and Agatston score ≥ 400 groups according to coronary artery calcium severity. Propensity score matching (PSM) was used to match DM (n =112) and non-DM (n =214) groups. Sensitivity, specificity, accuracy, and area under the curve (AUC) with 95 % confidence interval (CI) were calculated and compared. Sensitivity, specificity, accuracy, and AUC of FFRCT were 0.79, 0.96, 0.87, and 0.91 in DM patients and 0.82, 0.93, 0.89, and 0.89 in non-DM patients without significant difference (all p > 0.05) on a per-patient level. The accuracies of FFRCT had no significant difference among different coronary stenosis subgroups and between two coronary calcium subgroups (all p > 0.05) in the DM and non-DM groups. After PSM grouping, the accuracies of FFRCT were 0.88 in the DM group and 0.87 in the non-DM group without a statistical difference (p > 0.05). DM has no negative impact on the diagnostic accuracy of machine learning-based FFRCT. • ML-based FFRCT has a high discriminative accuracy of hemodynamic ischemia, which is not affected by DM. • FFRCT was superior to the CCTA alone for the detection of ischemia relevance of coronary artery stenosis in both DM and non-DM patients. • Coronary calcification had no significant effect on the diagnostic accuracy of FFRCT to detect ischemia in DM patients.

Agreement between single plane and biplane derived angiographic fractional flow reserve in patients with intermediate coronary artery stenosis.

Fractional flow reserve (FFR) is often used to evaluate the physiological severity of intermediate coronary stenoses, but less-invasive assessment methods are desirable. We evaluated the feasibility of angiographic FFR (angioFFR) calculated from two projections acquired simultaneously by a biplane C-arm system and angioFFR calculated from two projections acquired independently by one plane of the same biplane C-arm system. AngioFFR was validated against FFR in terms of detection of hemodynamically relevant coronary artery stenoses. Twenty-two Patients who underwent angiography and FFR for coronary artery disease were included. We used a non-commercial prototype to calculate biplane angioFFR for 22 vessels (19 LAD, 1 LCx, 2 RCA) and single plane angioFFR for 17 of the same 22 vessels. FFR < 0.8 was measured in 8 vessels. The Pearson correlation coefficients with FFR were 0.55 for single plane angioFFR and 0.61 for biplane angioFFR and the diagnostic accuracies were 88% (95% CI 73-100%) for single plane angioFFR and 86% (95% CI 72-100%) for biplane angioFFR. Bland-Altman plots revealed that compared with FFR, the limits of agreement for single plane angioFFR were - 0.07 to 0.19 (mean difference 0.06, p = 0.002) and the limits of agreement for biplane FFR were - 0.09 to 0.15 (mean difference 0.03, p = 0.03). In conclusion, angioFFR calculated from single or biplane acquisitions by a biplane C-arm is feasible and may evolve to a tool for less invasive imaging-based assessment of myocardial ischemia.

Coronary Computer Tomography Angiography in 2021-Acquisition Protocols, Tips and Tricks and Heading beyond the Possible.

Recent technological advances, together with an increasing body of evidence from randomized trials, have placed coronary computer tomography angiography (CCTA) in the center of the diagnostic workup of patients with coronary artery disease. The method was proven reliable in the diagnosis of relevant coronary artery stenosis. Furthermore, it can identify different stages of the atherosclerotic process, including early atherosclerotic changes of the coronary vessel wall, a quality not met by other non-invasive tests. In addition, newer computational software can measure the hemodynamic relevance (fractional flow reserve) of a certain stenosis. In addition, if required, information related to cardiac and valvular function can be provided with specific protocols. Importantly, recent trials have highlighted the prognostic relevance of CCTA in patients with coronary artery disease, which helped establishing CCTA as the first-line method for the diagnostic work-up of such patients in current guidelines. All this can be gathered in one relatively fast examination with minimal discomfort for the patient and, with newer machines, with very low radiation exposure. Herein, we provide an overview of the current technical aspects, indications, pitfalls, and new horizons with CCTA, providing examples from our own clinical practice.

Commentary: Vasodilator Myocardial Perfusion Cardiac Magnetic Resonance Imaging Is Superior to Dobutamine Stress Echocardiography in the Detection of Relevant Coronary Artery Stenosis: A Systematic Review and Meta-Analysis on Their Diagnostic Accuracy.

Commentary: Vasodilator Myocardial Perfusion Cardiac Magnetic Resonance Imaging Is Superior to Dobutamine Stress Echocardiography in the Detection of Relevant Coronary Artery Stenosis: A Systematic Review and Meta-Analysis on Their Diagnostic Accuracy.

The Interplay between Features of Plaque Vulnerability and Hemodynamic Relevance of Coronary Artery Stenoses

Fractional flow reserve (FFR) may not be immune from hemodynamic perturbations caused by both vessel and lesion related factors. The aim of this study was to investigate the impact of plaque- and vessel wall-related features of vulnerability on the hemodynamic effect of intermediate coronary stenoses. Methods and Results: In this cross-sectional study, patients referred to catheterization laboratory for clinically indicated coronary angiography were prospectively screened for angiographically intermediate stenosis (50–80%). Seventy lesions from 60 patients were evaluated. Mean angiographic stenosis was 62.1 ± 16.3%. After having performed FFR assessment, intravascular ultrasound (IVUS) was performed over the FFR wire. Virtual histology IVUS was used to identify the plaque components and thin cap fibroatheroma (TCFA). TCFA was significantly more frequent (65 vs. 38%, p = 0.026), and necrotic core volume (26.15 ± 14.22 vs. 16.21 ± 8.93 mm³, p = 0.04) was significantly larger in the positively remodeled than non-remodeled vessels. Remodeling index correlated with necrotic core volume (r = 0.396, p = 0.001) and with FFR (r = –0. 419, p = 0.001). With respect to plaque components, only necrotic core area (r = –0.262, p = 0.038) and necrotic core volume (r = –0.272, p = 0.024) were independently associated with FFR. In the multivariable model, presence of TCFA was independently associated with significantly lower mean FFR value as compared to absence of TCFA (adjusted, 0.71 vs. 0.78, p = 0.034). Conclusion: The current study demonstrated that for a given stenosis geometry, features of plaque vulnerability such as necrotic core volume, TCFA, and positive remodeling may influence the hemodynamic relevance of intermediate coronary stenoses.

Coronary Stenosis Physiology and Novel Technologies.

An accurate functional assessment of coronary artery stenosis is pivotal in the management and clinical outcomes of patients. The hemodynamic relevance of coronary artery stenoses can be assessed using coronary flow surrogates, namely fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR). This review provides an overview of these indexes, their clinical relevance, as well as a review of the literature supporting their use. It also reviews novel image-based FFR (e.g. FFRangio), the evidence showing the accuracy of this technique when compared to conventional wire-based techniques, as well as the clinical implications of non-invasive coronary artery stenosis functional assessments.

392Systematic review and meta-analysis on the diagnostic accuracy for the detection of relevant coronary artery stenosis of vasodilator myocardial perfusion CMR and dobutamine stress echocardiography

Abstract Background Relevance of coronary artery stenosis in patients with stabile coronary artery disease (SCAD) is defined by myocardial ischemia due to flow limitation. While FFR-guided treatment of SCAD is a class IA recommendation. The initial risk stratification with detection of relevant CAD can be facilitated by several myocardial imaging methods without any preference mentioned in current guidelines. Objectives This study aimed to systematically assess and to compare the diagnostic accuracy of vasodilator myocardial perfusion cardiovascular magnetic resonance imaging (pCMR) and dobutamine stress echocardiography (DSE) for the non-invasive detection of relevant SCAD through a meta-analysis, to enable an evidential preference in risk stratification. In contrast to previously published work, this meta-analysis explicitly included only studies with rigorous eligibility criteria and a narrowly prespecified definition of their invasive reference tests. Selection criteria A study was included if (1) CCA or FFR was used as a reference standard for diagnosing relevant SCAD, defined as &gt;70% stenosis or a value &lt;0.80 on FFR recordings, respectively; (2) sufficient data to permit analysis and to reconstruct contingency tables (explicitly true-positive, false-positive, false-negative and true-negative findings) was provided; (3) there was a minimal sample size of 20 patients; (4) assessment of myocardial perfusion reserve was performed using vasodilators adenosine or regadenoson for pCMR, and dobutamine used for echocardiography; and (5) the studies were of prospective design. Data collection and analysis: From the 5,634 studies identified, 1,306 relevant articles were selected after title screening. Just 47 fulfilled all inclusion criteria on full-text review, resulting in a total sample size of 4,742 patients. Data extraction was performed for each study by two reviewers independently.Pooled analysis was performed based on a random effects models. Results The sensitivity, specificity and diagnostic odds ratio (DOR) for pCMR were 0.88 (95% confidence interval (CI): 0.85–0.90), 0.84 (95% CI: 0.81–0.87), and 38 (95% CI: 29–49), and for DSE 0.72 (95% CI: 0.61–0.81), 0.89 (95% CI: 0.83–0.93), and 20 (95% CI: 9–46), respectively. Post-test probability was augmented by positive (likelihood ratio) LR of 5.5 (95% CI: 4.7–6.5) and negative LR of 0.14 (95% CI: 0.12–0.18) based on Bayes' theorem, as compared to LR of 6.3 (95% CI: 3.8, 10.4) and negative LR of 0.31 (95% CI: 0.21, 0.46) for DSE. The size of the prediction region on the hierarchical summary receiver operating characteristic (HSROC) plot for pCMR (0.29; 95% CI 0.11–0.77) was significantly smaller compared to the one of DSE (1.07; 95% CI 0.27–4.19; p&lt;0.01). Forrest plot pCMR Conclusion The results of this systematic review and meta-analysis show that pCMR is characterized by a superior diagnostic test accuracy of relevant SCAD compared to DSE and that it can refine the post-test probability of SCAD. Acknowledgement/Funding European Heart Academy of the European Society of Cardiology

Fibrillation atriale induite par une injection intracoronaire d’adénosine pendant une évaluation de la « fractional flow reserve »

Fractional flow reserve (FFR) measurement for functional evaluation of haemodynamic relevance of coronary artery stenoses is a well established and straightforward method applied on daily basis in cardiac catheterization laboratory; it is known to be reliable, reproducible and secure associated with a low rate of adverse events. We report the case of a 68-year-old man with no history of arrhythmias in whom intracoronary injection of adenosine for FFR assessment immediately induced atrial fibrillation mandating hospitalization for pharmacological cardioversion.

Diagnostic value of stress thallium-201/rest technetium-99m-sestamibi sequential dual isotope high-speed myocardial perfusion imaging for the detection of haemodynamically relevant coronary artery stenosis

BackgroundThe aim of this study was to determine the diagnostic accuracy of stress thallium-201/rest technetium-99m-sestamibi sequential dual-isotope high-speed myocardial perfusion imaging (DI-HS-MPI) against invasively determined fractional flow reserve (FFR). MethodsFifty-four consecutive patients prospectively underwent DI-HS-MPI before invasive coronary angiography. Perfusion was scored visually by summed stress score on a patient and coronary territory basis. Significant coronary artery disease (CAD) was defined by the presence of ≥ 90% stenosis/occlusion or fractional flow reserve ≤ 0.80 for coronary stenosis ≥ 50%. ResultsFFR was measured in 69 of 162 coronary vessels, with 1.28 ± 0.56 vessels assessed/patient. Sensitivity, specificity, and diagnostic accuracy of MPI for the detection of significant CAD were 92.8%, 69.2%, and 81.4%, on a patient basis, and 83.7%, 90.4%, and 88.8% by coronary territory. ConclusionsDI-HS-MPI accurately detects functionally significant CAD as defined by using FFR.

P188Is MRI-stress testing the new gold standard? A systematic review and meta-analysis on the diagnostic performance of cardiac imaging methods for the detection of relevant coronary artery stenosis

P188Is MRI-stress testing the new gold standard? A systematic review and meta-analysis on the diagnostic performance of cardiac imaging methods for the detection of relevant coronary artery stenosis

Coronary Angiography With Pressure Wire and Fractional Flow Reserve.

Approximately 800 000 coronary angiography procedures are per- formed in Germany each year, mainly in order to identify coronary artery stenoses. As a rule, revascularization is indicated only when coronary artery stenoses cause relevant ischemia, but this cannot be determined unequivocally by angiography alone. Pressure wire measurement and the measurement of fractional flow reserve (FFR) enable direct evaluation of the hemodynamic relevance of coronary artery stenoses during diagnostic coronary angiography. This review is based on publications retrieved by a selective search in PubMed focusing especially on large randomized trials, registry studies, and meta- analyses on either pressure wire measurement or FFR. According to a registry study from France, the hemodynamic evaluation of a stenosis during coronary angiography affected decisions about revascularization in 43% of cases. Randomized multicenter trials have shown that a combined end- point consisting of death, myocardial infarction, or revascularization arose signifi- cantly less commonly in the FFR group than in the group receiving angiography without FFR (13.2% versus 18.3%; p = 0.02), and that patients with one or more hemodynamically significant coronary artery stenoses (FFR ≤ 0.80) benefited more from revascularization than from medical management alone (event rate, 8.1% versus 19.5%; p <0.001). It was also shown that revascularization yields no benefit if relevant ischemia has been ruled out, even if the angiogram shows high-grade coronary artery stenoses. All cardiac catheter laboratories should be capable of performing pres- sure wire measurements and measurements of FFR and should do so regularly if ischemia due to coronary artery stenosis cannot be demonstrated non-invasively. A pathological FFR measurement is an indication for revascularization.

ESC/EACTS guidelines on myocardial revascularization 2018 : The most important innovations

The guidelines on myocardial revascularization published in 2018 are ajoint initiative of the European Society of Cardiology and the European Association for Cardio-Thoracic Surgery. To establish indications for myocardial revascularization by percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG), evidence of the functional relevance of coronary artery stenoses is needed either by non-invasive imaging function tests or intravascular hemodynamic measurements. The prognostic and symptomatic benefits of myocardial revascularization depend on whether complete revascularization can be achieved. This needs to be considered when choosing the most appropriate revascularization strategy. In addition, the individual operative risk, the technical feasibility, the presence of diabetes mellitus and the anatomical complexity of coronary artery disease, as assessed by the SYNTAX score, are key criteria when choosing the optimal method of revascularization. For PCI radial artery access and the general use of drug-eluting stents are recommended. For CABG multiple arterial grafts should be strived for including the radial artery for treatment of high-grade coronary stenosis.

Effect of iterative reconstruction and temporal averaging on contour sharpness in dynamic myocardial CT perfusion: Sub-analysis of the prospective 4D CT perfusion pilot study.

PurposeMyocardial computed tomography perfusion (CTP) allows the assessment of the functional relevance of coronary artery stenosis. This study investigates to what extent the contour sharpness of sequences acquired by dynamic myocardial CTP is influenced by the following noise reduction methods: temporal averaging and adaptive iterative dose reduction 3D (AIDR 3D).Materials and methodsDynamic myocardial CT perfusion was conducted in 29 patients at a dose level of 9.5±2.0 mSv and was reconstructed with both filtered back projection (FBP) and strong levels of AIDR 3D. Temporal averaging to reduce noise was performed as a post-processing step by combining two, three, four, six and eight original consecutive 3D datasets. We evaluated the contour sharpness at four distinct edges of the left-ventricular myocardium based on two different approaches: the distance between 25% and 75% of the maximal grey value (d) and the slope in the contour (m).ResultsIterative reconstruction reduced contour sharpness: both measures of contour sharpness performed better for FBP than for AIDR 3D (d = 1.7±0.4 mm versus 2.0±0.5 mm, p>0.059 at all edges; m = 255.9±123.9 HU/mm versus 160.6±123.5 HU/mm; p<0.023 for all edges). Increasing levels of temporal averaging degraded contour sharpness. When FBP reconstruction was applied, contour sharpness was best without temporal averaging (d = 1.7±0.4 mm, m = 255.9±123.9 HU/mm) and poorest for the strongest levels of temporal averaging (d = 2.1±0.3 mm, m = 142.2±104.9 HU/mm; comparison between lowest and highest temporal averaging level: for d p>0.052 at all edges and for m p<0.001 at all edges).ConclusionThe use of both temporal averaging and iterative reconstruction degrades objective contour sharpness parameters of dynamic myocardial CTP. Thus, further advances in image processing are needed to optimise contour sharpness of 4D myocardial CTP.

Relationship of the Duke jeopardy score combined with minimal lumen diameter as assessed by computed tomography angiography to the hemodynamic relevance of coronary artery stenosis

ObjectivesTo study the diagnostic performance of the ratio between the Duke jeopardy score (DJS) and the minimal lumen diameter (MLD) (DJS/MLDCT ratio) as assessed by coronary computed tomographic angiography (CTA) for differentiating functionally significant from non-significant coronary artery stenoses, with reference to invasive fractional flow reserve (FFR). MethodsPatients who underwent both coronary CTA and FFR measurement during invasive coronary angiography (ICA) within 2 weeks were retrospectively included in the study. Invasive FFR measurement was performed in patients with intermediate to severe coronary stenoseis. DJS/MLDCT ratio and anatomical parameters were recorded. Lesions with FFR ≤0.80 were considered to be functionally significant. ResultsOne hundred and sixty-one patients with 175 lesions were included into the analysis. Diameter stenosis in CT, area stenosis, plaque burden, lesion length (LL), ICA-based stenosis degree, DJS, LL/MLD4 ratio, DJS/MLA ratio as well as DJS/MLD ratio were all significantly different between hemodynamically significant and non-significant lesions (p<0.05 for all). ROC curve analysis determined the optimal cut-off value for DJS/MLDCT ratio to be 1.96 (area under curve = 0.863, 95 % confidence interval = 0.803–0.910), yielding a high diagnostic accuracy (86.9%, 152/175). ConclusionsIn coronary artery stenoses detected by coronary CTA, the DJS/MLD ratio is able to predict hemodynamic relevance.