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Despite decades of research and major innovations in technology, cardiovascular disease remains the leading cause of death globally. Our understanding of major cardiovascular events and their prevention is centred around the atherosclerotic plaque and the processes that ultimately lead to acute plaque rupture. Recent advances in hybrid imaging technology allow the combination of high spatial resolution and anatomical detail with molecular assessments of disease activity. This provides the ability to identify vulnerable plaque characteristics and differentiate active and quiescent disease, with the potential to improve patient risk stratification. Combined positron emission tomography and computed tomography is the prototypical non-invasive hybrid imaging technique for coronary artery plaque assessment. In this review we discuss the current state of play in the field of hybrid coronary atherosclerosis imaging.

Objective Next to myocardial perfusion, single-photon emission computed tomography (SPECT) also allows for assessment of non-perfusion parameters such as transient ischemic dilatation (TID) and a reduction of ejection fraction (EF) with stress imaging. The present study aimed to evaluate the diagnostic value of TID and EF reserve for the detection of significant multivessel coronary artery disease (CAD). Methods A total of 206 patients with suspected stable coronary artery disease prospectively underwent gated stress-rest 99mTc-tetrofosmin SPECT and invasive coronary angiography with routine fractional flow reserve (FFR) measurements, regardless of imaging results. Left ventricular (LV) volumes, TID and EF reserve were assessed and compared with FFR defined severity of CAD. Results According to FFR, 92 (45%) patients had significant CAD, whereas 25 (12%) showed two vessel disease and 22 (11%) showed three vessel disease (3-VD). With an increasing extent of CAD, TID values and EF reserve did not significantly change (p = 0.07 and p = 0.42 for trend, respectively). Conversely, absolute LV volumes and EF differed significantly among groups of CAD severity (p < 0.01 for all trends). Conclusion SPECT derived TID and EF reserve did not differ between patients with high risk CAD (3-VD) and low risk or no significant CAD. Therefore the present results advocate exert caution when using these ancillary findings in clinical practice.

Objectives The randomized clinical VANISH (Impact of Vascular Reparative Therapy on Vasomotor Function and Myocardial Perfusion: A Randomized [15O]H2O PET/CT Study) trial was conducted to assess quantitative myocardial blood flow (MBF) during resting, hyperemia, and cold pressor testing (CPT) with positron emission tomographic perfusion imaging after the implantation of a bioresorbable everolimus-eluting scaffold compared with a drug-eluting stent. Background Long-term resorption of the bioresorbable everolimus-eluting scaffold reinstates normal vessel geometry, allowing natural regeneration of the newly formed endothelium with revival of vasomotor function. Methods Sixty patients (18 to 65 years of age) with single-vessel disease and type A or B1 lesions were randomized in a 1-to-1 fashion. Approximately 1 month, 1 year, and 3 years after device implantation, patients underwent [15O]H2O cardiac positron emission tomography. The primary endpoint was the interaction of device type and evolution over time of hyperemic MBF, coronary flow reserve, or CPT reserve. At 3-year follow-up, control invasive coronary angiography with optical coherence tomography was performed. Results Fifty-nine (98%), 56 (93%), and 51 (85%) patients successfully completed 1-month, 1-year, and 3-year follow-up positron emission tomography, respectively, and no culprit vessel events were registered during follow-up time. The primary study endpoint (i.e., interaction between device type and time) was nonsignificant for hyperemic MBF, CPT reserve, and coronary flow reserve (p > 0.05 for all). In all patients, hyperemic MBF decreased from 1 to 3 years (p = 0.02), while coronary flow reserve was lower at 3-year follow-up compared with 1-month and 1-year follow-up (p = 0.03 for both). After 3 years, percentage area stenosis measured with optical coherence tomography was higher within the bioresorbable everolimus-eluting scaffold compared with the drug-eluting stent (p = 0.03). Conclusions The hypothesized beneficial effects of scaffold resorption did not translate to improved MBF during maximal hyperemia or endothelium-dependent vasodilation by CPT.

A myocardial ischemic burden (IB) of 10% or more denotes high risk patients who benefit from revascularization. This threshold has been assessed by SPECT, the higher resolution of PET presumably results in a better detection of the extent and severity of ischemia. As such, a PET-derived IB might

Current guidelines advocate viability assessment before revascularization of chronic coronary total occlusions (CTO). The present study evaluated associations between coronary collaterals and myocardial viability assessed by cardiac magnetic resonance (CMR) imaging in patients with a CTO. Patients

The randomized clinical VANISH (Impact of Vascular Reparative Therapy on Vasomotor Function and Myocardial Perfusion: A Randomized [Long-term resorption of the bioresorbable everolimus-eluting scaffold reinstates normal vessel geometry, allowing natural regeneration of the newly formed endothelium with revival of vasomotor function.Sixty patients (18 to 65 years of age) with single-vessel disease and type A or B1 lesions were randomized in a 1-to-1 fashion. Approximately 1 month, 1 year, and 3 years after device implantation, patients underwent [Fifty-nine (98%), 56 (93%), and 51 (85%) patients successfully completed 1-month, 1-year, and 3-year follow-up positron emission tomography, respectively, and no culprit vessel events were registered during follow-up time. The primary study endpoint (i.e., interaction between device type and time) was nonsignificant for hyperemic MBF, CPT reserve, and coronary flow reserve (p0.05 for all). In all patients, hyperemic MBF decreased from 1 to 3 years (p = 0.02), while coronary flow reserve was lower at 3-year follow-up compared with 1-month and 1-year follow-up (p = 0.03 for both). After 3 years, percentage area stenosis measured with optical coherence tomography was higher within the bioresorbable everolimus-eluting scaffold compared with the drug-eluting stent (p = 0.03).The hypothesized beneficial effects of scaffold resorption did not translate to improved MBF during maximal hyperemia or endothelium-dependent vasodilation by CPT.

Aims: Despite high variability in coronary anatomy, quantitative positron emission tomography (PET) perfusion in coronary territories is traditionally calculated according to the American Heart Association (AHA) 17-segments model. This study aimed to assess the impact of individualized segmentation of myocardial segments on the diagnostic accuracy of hyperaemic myocardial blood flow (MBF) values for haemodynamically significant coronary artery disease (CAD).Methods and results: Patients with suspected CAD (n = 204) underwent coronary computed tomography angiography (CCTA) and [15O]H2O PET followed by invasive coronary angiography with fractional flow reserve assessment of all major coronary arteries. Hyperaemic MBF per vascular territory was calculated using both standard segmentation according to the AHA model and individualized segmentation, in which CCTA was used to assign coronary arteries to PET perfusion territories. In 122 (59.8%) patients, one or more segments were redistributed after individualized segmentation. No differences in mean MBF values were seen between segmentation methods, except for a minor difference in hyperaemic MBF in the LCX territory (P = 0.001). These minor changes resulted in discordant PET-defined haemodynamically significant CAD between the two methods in only 5 (0.8%) vessels. The diagnostic value for detecting haemodynamically significant CAD did not differ between individualized and standard segmentation, with area under the curves of 0.79 and 0.78, respectively (P = 0.34).Conclusions: Individualized segmentation using CCTA-derived coronary anatomy led to redistribution of standard myocardial segments in 60% of patients. However, this had little impact on [15O]H2O PET MBF values and diagnostic value for detecting haemodynamically significant CAD did not change. Therefore, clinical impact of individualized segmentation seems limited.

Background: The main goal of coronary revascularization is to restore myocardial perfusion in case of ischemia, causing coronary artery disease. Yet, little is known on the effect of revascularization on absolute myocardial blood flow (MBF). Therefore, the present prospective study assesses the impact of coronary revascularization on absolute MBF as measured by [ 15 O]H 2 O positron emission tomography and fractional flow reserve (FFR) in patients with stable coronary artery disease. Methods and Results: Fifty-three patients (87% men, mean age 58.7±9.0 years) with suspected coronary artery disease were included prospectively. All patients underwent serial [ 15 O]H 2 O positron emission tomography perfusion imaging at baseline and after revascularization by either percutaneous coronary intervention (PCI) or coronary artery bypass graft surgery. FFR was routinely measured at baseline and directly post-PCI. After revascularization, regional rest and stress MBF improved from 0.77±0.16 to 0.86±0.25 mL/min/g and from 1.57±0.59 to 2.48±0.91 mL/min/g, respectively, yielding an increase in coronary flow reserve from 2.02±0.69 to 2.94±0.94 ( P P r = 0.74 and r = 0.71, respectively, P P =0.02). However, patients undergoing bypass grafting had a more advanced stage of coronary artery disease and more incomplete revascularizations. Conclusion: Successful coronary revascularization has a significant and positive impact on absolute myocardial perfusion as assessed by serial quantitative [ 15 O]H 2 O positron emission tomography. Notably, improvement of FFR after PCI was directly related to the increase in hyperemic MBF.

This study sought to compare Doppler flow velocity reserve (CFRCoronary flow reserve (CFR) is an important parameter for assessing coronary vascular function. To date, 2 techniques are available for invasive assessment of CFR: Doppler flow velocity and thermodilution. Although these techniques have been compared with each other, neither has been compared with [CFR was assessed in 98 vessels of 40 consecutive stable patients with suspected coronary artery disease. Patients underwent [The quality of Doppler flow velocity traces was significantly lower than that of thermodilution curves (p 0.001). A moderate correlation was observed between CFRCoronary flow reserve, determined using Doppler flow velocity, has superior agreement with [

Contains fulltext : 209425.pdf (Publisher’s version ) (Closed access) Aims: The longitudinal myocardial blood flow (MBF) gradient derived from positron emission tomography (PET) has been proposed as an emerging non-invasive index of haemodynamically significant coronary artery disease (CAD). This study aimed to investigate the diagnostic value of longitudinal MBF gradient for the presence of haemodynamically significant CAD. Methods and results: A total of 204 patients (603 vessels) with suspected CAD underwent [15O]H2O PET followed by invasive coronary angiography with fractional flow reserve (FFR) of all major coronary arteries. Longitudinal base-to-apex MBF gradients were assessed by two methods, using MBF in apical and mid (Method 1) or in apical and basal (Method 2) myocardial segments to calculate the gradient. The hyperaemic longitudinal MBF gradient was only weakly correlated with FFR (Method 1: r = 0.12, P = 0.02; Method 2: r = 0.22, P < 0.001). The hyperaemic longitudinal MBF gradient (by both methods), had lower diagnostic value when compared with hyperaemic MBF for the presence of haemodynamically significant CAD, defined as an FFR

Background: Fractional fow reserve (FFR) is, next to lesion severity, affected by plaque vulnerability as assessed by coronary computed tomography angiography (CCTA) and associated with imminent acute coronary syndromes. Instantaneous wave-free ratio (iFR) has recently emerged as an alternative for FFR to interrogate coronary lesions for ischemia. It is, however, unknown whether vasodilator free assessment with iFR is associated with plaque stability similarly as FFR. The current substudy of the PACIFIC trial explores the impact of CCTA derived unfavorable plaque features on both hyperemic and non-hyperemic fow indices in order to detect vulnerable plaques. Methods: Of 119 patients (62% men, age 58 ± 8.6 years) with suspected coronary artery disease, 257 vessels were prospectively evaluated. Each patient underwent 256-slice CCTA to assess stenosis severity and plaque features (positive remodeling (PR), low attenuation plaque (LAP), spotty calcifcation (SC) and napkin ring sign (NRS)), as well as intracoronary pressure measurements (FFR, iFR, resting Pd/Pa and pressure ratio during adenosine within the wave-free period (iFRa)). CCTA derived plaque characteristics were related to these invasive pressure measurements. Results: Atherosclerotic plaques were present in 170 (66%) coronary arteries. On a per-vessel basis, luminal stenosis severity was signifcantly associated with impaired FFR, iFR, resting Pd/Pa and iFRa. Multivariable analysis revealed that PR and LAP were independently related to an impaired FFR (p = 0.006 and p = 0.038, respectively) and iFRa (p = 0.005 and p = 0.027, respectively), next to stenosis severity (p

Purpose Traditionally, interpretation of myocardial perfusion imaging (MPI) is based on visual assessment. Computer-based automated analysis might be a simple alternative obviating the need for extensive reading experience. Therefore, the aim of the present study was to compare the diagnostic performance of automated analysis with that of expert visual reading for the detection of obstructive coronary artery disease (CAD). Methods 206 Patients (64% men, age 58.2 ± 8.7 years) with suspected CAD were included prospectively. All patients underwent 99mTc-tetrofosmin single-photon emission computed tomography (SPECT) and invasive coronary angiography with fractional flow reserve (FFR) measurements. Non-corrected (NC) and attenuation-corrected (AC) SPECT images were analyzed both visually as well as automatically by commercially available SPECT software. Automated analysis comprised a segmental summed stress score (SSS), summed difference score (SDS), stress total perfusion deficit (S-TPD), and ischemic total perfusion deficit (I-TPD), representing the extent and severity of hypoperfused myocardium. Subsequently, software was optimized with an institutional normal database and thresholds. Diagnostic performances of automated and visual analysis were compared taking FFR as a reference. Results Sensitivity did not differ significantly between visual reading and most automated scoring parameters, except for SDS, which was significantly higher than visual assessment (p

The noninvasive diagnosis of coronary artery disease (CAD) is a challenging task. Traditionally, myocardial perfusion imaging (MPI) has been widely used for this purpose whereby cardiac positron emission tomography (PET) is considered the gold standard. Alternatively, noninvasive anatomical imaging of coronary atherosclerosis with coronary computed tomography angiography (CCTA) has recently been successfully implemented in clinical practice. Cardiac hybrid imaging consists of the fusion of these modalities and provides detailed information on the presence and extent of CAD including its functional consequences on myocardial perfusion. This type of comprehensive imaging, obtained within a single session using a PET/CT scanner, appears to have superior diagnostic and prognostic value as compared with either stand-alone test. This review discusses the literature on the incremental value of hybrid cardiac PET/CT imaging for patients suspected of CAD.

Importance: At present, the choice of noninvasive testing for a diagnosis of significant coronary artery disease (CAD) is ambiguous, but nuclear myocardial perfusion imaging with single-photon emission tomography (SPECT) or positron emission tomography (PET) and coronary computed tomography angiography (CCTA) is predominantly used for this purpose. However, to date, prospective head-to-head studies are lacking regarding the diagnostic accuracy of these imaging modalities. Furthermore, the combination of anatomical and functional assessments configuring a hybrid approach may yield improved accuracy.Objectives: To establish the diagnostic accuracy of CCTA, SPECT, and PET and explore the incremental value of hybrid imaging compared with fractional flow reserve.Design, Setting, and Participants: A prospective clinical study involving 208 patients with suspected CAD who underwent CCTA, technetium 99m/tetrofosmin-labeled SPECT, and [15O]H2O PET with examination of all coronary arteries by fractional flow reserve was performed from January 23, 2012, to October 25, 2014. Scans were interpreted by core laboratories on an intention-to-diagnose basis. Hybrid images were generated in case of abnormal noninvasive anatomical or functional test results.Main Outcomes and Measures: Hemodynamically significant stenosis in at least 1 coronary artery as indicated by a fractional flow reserve of 0.80 or less and relative diagnostic accuracy of SPECT, PET, and CCTA in detecting hemodynamically significant CAD.Results: Of the 208 patients in the study (76 women and 132 men; mean [SD] age, 58 [9] years), 92 (44.2%) had significant CAD (fractional flow reserve ≤0.80). Sensitivity was 90% (95% CI, 82%-95%) for CCTA, 57% (95% CI, 46%-67%) for SPECT, and 87% (95% CI, 78%-93%) for PET, whereas specificity was 60% (95% CI, 51%-69%) for CCTA, 94% (95% CI, 88%-98%) for SPECT, and 84% (95% CI, 75%-89%) for PET. Single-photon emission tomography was found to be noninferior to PET in terms of specificity (P .99) using the predefined absolute margin of 10%. Diagnostic accuracy was highest for PET (85%; 95% CI, 80%-90%) compared with that of CCTA (74%; 95% CI, 67%-79%; P = .003) and SPECT (77%; 95% CI, 71%-83%; P = .02). Diagnostic accuracy was not enhanced by either hybrid SPECT and CCTA (76%; 95% CI, 70%-82%; P = .75) or by PET and CCTA (84%; 95% CI, 79%-89%; P = .82), but resulted in an increase in specificity (P = .004) at the cost of a decrease in sensitivity (P = .001).Conclusions and Relevance: This controlled clinical head-to-head comparative study revealed PET to exhibit the highest accuracy for diagnosis of myocardial ischemia. Furthermore, a combined anatomical and functional assessment does not add incremental diagnostic value but guides clinical decision-making in an unsalutary fashion.

Item does not contain fulltext Aims: Previous studies on invasive assessment of collateral function in patients with a chronic total occlusion (CTO) have displayed only a limited increase in collateral flow and high occurrence of coronary steal during pharmacological stress. This could question the necessity for ischaemia testing prior to revascularization of CTOs in the presence of myocardial viability. The purpose of the present study was to determine the prevalence of perfusion impairments in patients with a CTO as assessed by [15O]H2O positron emission tomography (PET). Methods and results: Seventy-six consecutive patients (60 men, 62 +/- 10 years) with a documented CTO and preserved left ventricular ejection fraction (LVEF) were included. All patients underwent PET to assess (hyperaemic) myocardial blood flow (MBF) and coronary flow reserve (CFR). Collateral connection score was 0 in 7 (9%), 1 in 13 (17%), and 2 in 56 (74%) of the cases, with predominantly a high Rentrop grade (96% >/=2). MBF of the target area during hyperaemia was significantly lower when compared with the remote area (1.37 +/- 0.37 vs. 2.63 +/- 0.71 mL min-1 g-1, P < 0.001). Target to remote ratio during hyperaemia was on average 0.54 +/- 0.13, and 73 (96%) patients demonstrated a significantly impaired target to remote ratio (/=2.50, whereas coronary steal (CFR

Contains fulltext : 177040.pdf (Publisher’s version ) (Closed access) OBJECTIVE: To determine the impact of right ventricular side branch (RVB) occlusion, during percutaneous coronary interventions (PCIs) of chronic total occlusions (CTOs) of the right coronary artery (RCA), on right ventricular (RV) function. BACKGROUND: Developments in PCI techniques have expanded PCI CTO feasibility. However, the utilization of dissection and reentry techniques and extensive stent implantation increases the risk of coronary side branch occlusion. METHODS: Fifty-four patients (80% male, 63+/-10years) evaluated with cardiac magnetic resonance imaging (CMR) prior and three months after successful PCI CTO RCA (median: 99days, IQR: 92-105days) were included. Right ventricular end-diastolic volume (RVEDV), end-systolic volume (RVESV), and ejection fraction (RVEF) were quantified on CMR images. Occurrence of RVB occlusion and/or RVB recruitment was assessed using procedural angiograms. RESULTS: RVB occlusion was observed in 12 patients (22%), while RVB recruitment occurred in seven patients (13%). Overall, RVEF was comparable between baseline and follow-up (53.8+/-5.8 vs. 53.9+/-5.8%, p=0.95). RVB occlusion was not associated with a significant change in RVEDV or RVEF (156.9+/-36.3 vs. 162.1+/-35.5mL, p=0.30 and 54.2+/-3.9 vs. 52.7+/-4.4%, p=0.19, respectively); however a trend was observed for an increase of RVESV (72.5+/-20.0 vs. 77.4+/-20.7mL, p=0.05) at follow-up. RVB recruitment did not result in a significant improvement of RVEF (55.4+/-4.6 vs. 56.1+/-5.3%, p=0.75). CONCLUSION: RVB occlusion was not associated with a significant decreased RVEF at follow-up, although the results suggested a limited increase of RVESV.

Item does not contain fulltext AIMS: The aim of the present study was to investigate the effects of successful PCI CTO on absolute myocardial blood flow (MBF) and functional recovery. METHODS AND RESULTS: Patients with a documented CTO were prospectively examined for ischaemia and viability with [15O]H2O positron emission tomography (PET) and late gadolinium enhancement cardiac magnetic resonance imaging (LGE-CMR). Sixty-nine consecutive patients, in whom PCI was successful, underwent follow-up PET and CMR after approximately 12 weeks to evaluate potential improvement of MBF as well as systolic function. After PCI, stress MBF in the CTO area increased from 1.22+/-0.36 to 2.40+/-0.90 mL.min-1.g-1 (p

Quantitative flow ratio (QFR) has emerged as a promising tool assessing the significance of coronary artery disease (CAD) using solely cine coronary contrast images acquired during invasive coronary angiography (ICA) to obtain QFR values equivalent to fractional flow reserve (FFR). Our objective was

Myocardial perfusion imaging using positron emission tomography (PET) is a valuable tool in the diagnosis of coronary artery disease. And although PET using [15O]H2O has a high diagnostic accuracy for predicting coronary artery disease in routine clinical practices [(1)][1], left ventricular (LV)

Chronic total coronary occlusions (CTO) are documented in approximately one fifth of diagnostic invasive coronary angiographies (ICA). Percutaneous coronary interventions (PCI) of CTO are challenging and are accompanied by higher complication and lower success rates in comparison with non-CTO PCI. Scrutinous evaluation of ischemia and viability to justify percutaneous revascularization is therefore of importance to select eligible patients for such a procedure. Furthermore, knowledge of the anatomical features of the occlusion may predict the chances of success of PCI CTO and could even guide the procedural strategy to augment the likelihood of recanalization. Positron emission tomography (PET) is unequivocally accepted as the reference standard for ischemia and viability testing, whereas coronary computed tomography angiography (CCTA) currently allows for non-invasive detailed three-dimensional imaging of the coronary anatomy that adds morphological information over two-dimensional ICA. Hybrid PET/CT could therefore be useful for optimal patient selection as well as procedural planning. This review discusses the potential value of PET/CT to guide PCI in CTOs.

Background: Traditionally, the interpretation of myocardial perfusion imaging is based on visual analysis. A computer-based automated analysis might be a simple alternative obviating the need for extensive reading experience. Therefore, the aim of the present study is to compare the diagnostic

Background: Next to coronary lesion severity, atherosclerotic plaque characteristics may also affect downstream myocardial perfusion. The purpose of the present study was to evaluate the association between quantitative plaque burden and plaque morphology obtained using coronary computed tomography

Instantaneous hyperemic diastolic velocity pressure slope (IHDVPS) is a measure of coronary conductance. IHDVPS is defined as the slope of the relationship between intracoronary hyperaemic pressure and Doppler flow velocity flow in mid to end diastole. In the presence of coronary artery disease

Chronic total occlusions (CTO) with well functioning collaterals are frequently assumed to provide sufficient blood flow to prevent myocardial ischemia. Previous studies on invasive assessment of collateral function during pharmalogical stress, however, have displayed only a limited increase in

Background and aims: In this study, we investigated whether increased renin angiotensin aldosterone system (RAAS) activation and endothelin-1 levels are related to coronary artery calcium (CAC) score, total plaque volume (TPV), high risk plaque, hyperemic myocardial blood flow (MBF) and coronary microvascular dysfunction (CMD). Methods: In a prospective, observational, cross-sectional cohort, renin as a marker for RAAS activation and endothelin-1 were measured in peripheral venous blood of 205 patients (64% men; age 58 ± 8.7 years) with suspected coronary artery disease (CAD) who underwent coronary computed tomography angiography (CCTA), [ 15O]H 2O positron emission tomography (PET) perfusion imaging and invasive fractional flow reserve (FFR) measurements. Patients were categorized into three groups based on FFR (≤0.80) and hyperemic MBF