Table 1 - uploaded by Venkatesh L Murthy
Content may be subject to copyright.
Source publication
Positron emission tomography (PET) is increasingly being applied in the evaluation of myocardial perfusion. Cardiac PET can be performed with an increasing variety of cyclotron- and generator-produced radiotracers. Compared with single photon emission computed tomography, PET offers lower radiation exposure, fewer artifacts, improved spatial resolu...
Similar publications
Background:
Recent evidence suggests that the diagnostic accuracy of myocardial perfusion imaging is improved by quantifying stress myocardial blood flow (MBF) in absolute terms. We evaluated a comprehensive quantitative (13)N-ammonia positron emission tomography ((13)NH3-PET) diagnostic panel, including stress MBF, coronary flow reserve (CFR), an...
Citations
... The presence and severity of abnormal findings at radionuclide MPI is strongly related to the presence and severity of CAD. 7 Moreover, cardiac MPI by positron emission tomography (PET) is considered the gold standard for noninvasive assessment of absolute myocardial blood flow and myocardial perfusion reserve (MPR), which is able to provide both diagnostic and prognostic information. [8][9][10][11] During last years, the introduction in the clinical practice of cadmium-zinc-telluride (CZT) cameras allowed to perform absolute quantification of MBF and MPR by using SPECT technology. 12,13 The diagnostic ability of CZT SPECT in identifying obstructive CAD has been previously explored. ...
... Positron emission tomography (PET) computed tomography (CT) myocardial perfusion imaging (MPI) is increasingly used for this task. 1 PET/CT MPI has several distinct advantages in evaluating CAD over other available non-invasive tools. 1 In addition to improved spatial resolution and reduced radiation exposure, 1 the improved count statistics enable PET MPI to determine several parameters with higher accuracy compared to single photon emission computed tomography (SPECT). Early dynamic acquisitions allow absolute quantification of myocardial blood flow and calculation of myocardial flow reserve (MFR). 2 MFR has high diagnostic accuracy for obstructive CAD and is a powerful predictor of cardiovascular events even in patients with normal regional myocardial perfusion. ...
... Positron emission tomography (PET) computed tomography (CT) myocardial perfusion imaging (MPI) is increasingly used for this task. 1 PET/CT MPI has several distinct advantages in evaluating CAD over other available non-invasive tools. 1 In addition to improved spatial resolution and reduced radiation exposure, 1 the improved count statistics enable PET MPI to determine several parameters with higher accuracy compared to single photon emission computed tomography (SPECT). Early dynamic acquisitions allow absolute quantification of myocardial blood flow and calculation of myocardial flow reserve (MFR). 2 MFR has high diagnostic accuracy for obstructive CAD and is a powerful predictor of cardiovascular events even in patients with normal regional myocardial perfusion. ...
... Our results are consistent with previous studies that have reported that GMPS is an accurate method for detecting patients with 3VD. 23,24 It is important to highlight these findings, which have demonstrated that SSS is superior to SRS and SDS as predictors of significant CAD and mortality. 4 Regarding other mechanical variables, such as LVEF in both stress and rest phase, we found that these variables had low AUROC values for discriminating patients with 3VD, unlike previous reports in the literature. ...
Background
Three-vessel disease (3VD) is a cardiovascular disorder that affects the three main coronary arteries. Gated myocardial perfusion SPECT (GMPS) evaluates ventricular function, synchrony, and myocardial perfusion. However, the diagnostic performance of GMPS parameters to assess 3VD has not been fully explored.AimsTo assess the univariate performance capacity of GMPS parameters, and to evaluate whether phase parameters could provide additional predictive value for the detection of patients with 3VD compared to control subjects.Methods
We designed paired retrospective samples of GMPS images of patients with 3VD (stenosis > 70% of left anterior descending, right coronary, and circumflex coronary arteries) and without 3VD. A GMPS in rest-stress protocol was performed using 99mTc-Sestamibi and thallium and analyzed with the 3D method. Area under the receiver-operating characteristic curves (AUROC), decision curve analyses and diagnostic test performance were obtained for univariable analyses and stepwise binomial logistic regression for multivariable performance.Results474 Patients were included: 237 with 3VD (84% males, mean age 61.7 ± 9.9 years) and 237 with normal GMPS (51% women, mean age 63.8 ± 10.6 years). The highest AUROC for perfusion parameters were recorded for SSS, SRS and TID. For dyssynchrony parameters, both entropy and bandwidth in rest and stress phases displayed the highest AUROC and diagnostic capacity to detect 3VD. A multivariate model with SRS ≥ 4, SDS ≥ 2, TID > 1.19 and sBW ≥ 48° displayed the highest diagnostic capacity (0.923 [95% CI 0.897-0.923]) to detect 3VD.Conclusion
Perfusion and dyssynchrony were the parameters which were most able to discriminate patients with 3VD from those who did not have CAD.
... MFR has been correlated with risk of CV outcomes in nontransplant patients. [9][10][11][12][13] There are emerging data that PET/CT MPI may have superior diagnostic accuracy (sensitivity 81%-89%, negative predictive value 87%-94%) compared with CT angiography for coronary ischemia. 14 PET/CT MPI is also very attractive in this population given that it has no nephrotoxicity and is not affected by chronic vasodilation that limits other modalities of functional CAD testing. ...
Background. The optimal cardiovascular (CV) risk stratification in liver transplant (LT) candidates remains unclear. The aim of this study was to evaluate concordance of findings between dobutamine stress echocardiography (DSE), positron emission tomography/computed tomography myocardial perfusion imaging (PET/CT MPI), and left heart catheterization in adult LT candidates.
Methods. Data on 234 consecutive adult LT candidates from February 2015 to June 2018 with PET/CT MPI were reviewed. Adverse CV outcomes were adjudicated via chart review by a board-certified cardiologist.
Results. Median age was 60.8, body mass index 30.2 kg/m2, and model of end-stage liver disease–sodium 14; 61% were male, and 54% had diabetes. Thirty-seven percent had nonalcoholic steatohepatitis and 29% alcohol-related liver disease. Sixty-five percent of patients had a DSE, of which 41% were nondiagnostic. No factors were independently associated with having a nondiagnostic DSE. The median global myocardial flow reserve correlated positively with hemoglobin and negatively with model of end-stage liver disease–sodium, age, ejection fraction, and body mass index. Moderate/high-risk MPIs were associated with older age and known CV disease. In patients with 2 cardiac testing modalities, findings were concordant in 87%. Eleven of 53 LT recipients experienced an adverse CV outcome, but no independent predictors were identified for this outcome.
Conclusions. Results of different cardiac risk-stratification modalities were concordant across modalities the majority of the time in LT candidates, although these findings were not independently correlated with risk of post-LT CV outcomes. Given the high rates of nondiagnostic DSEs in this population, PET/CT MPI may be the preferred CV risk-stratification modality in older patients and those with known CV disease.
... Myocardial perfusion imaging with SPECT enables the assessment of CAD noninvasively. It has been reported that myocardial perfusion imaging with PET has higher diagnostic accuracy than SPECT [24]. In nuclear studies for RA, dipyridamole thallium has shown microvasculitis and micro-thrombosis without evidence of MI or clinical symptoms [4]. ...
... In nuclear studies for RA, dipyridamole thallium has shown microvasculitis and micro-thrombosis without evidence of MI or clinical symptoms [4]. Values of erythrocyte sedimentation rate (ESR) and rheumatoid factors such as IgM or IgG were found to be higher in RA with perfusion defects than normal perfusion RA [24]. The high costs associated with the technology have a limited role in these conditions [25] and require further studies. ...
For systemic diseases like rheumatoid arthritis, systemic lupus erythematosus (SLE), systemic sclerosis, systemic vasculitis, myopathies, and mixed connective tissue diseases, cardiac disease is a major contributing factor for morbidity and mortality. The cardiovascular manifestations are the result of various pathophysiological components, which complicate management. Furthermore, the signs and symptoms can be subtle and missed due to the complex nature of the underlying condition. As a result, various imaging approaches play an imperative role in diagnosis and prognosis. The evolving role of these modalities could lead to risk stratification and improved therapies in the future. In conclusion, our review article will highlight the role of cardiac imaging in the evaluation of cardiac involvement for systemic diseases.
... Comparatively, positron emission tomography (PET) has improved spatial resolution and most scanners offer rapid attenuation correction with built in computed tomography (CT) integration. Further, lower doses of radiation, superior diagnostic accuracy, improved sensitivity in diffuse coronary artery disease, and the capability of quantifying myocardial blood flow in absolute units has allowed cardiac PET to emerge as an attractive alternative to SPECT, limited primarily by cost and availability [1][2][3]. ...
... Quantitative PET dynamic image interpretation. Data were analyzed on our quantitative analysis system (UW-QPP) which was previously validated for NH 3 and Rb-82 studies [24] and shown by Nesterov et al to provide very similar results to other Rb-82 quantitative packages [25]. Absolute Myocardial blood flow (MBF), flow per unit mass (in mL/min/g) [26], was quantified with an axially distributed model [25] and global rest MBF, stress MBF, and myocardial flow reserve (MFR) [27], ratio stress to rest MBF, were recorded for all exams. ...
Background:
Cardiac PET can provide quantitative myocardial blood flow (MBF) estimates. The frequency and clinical significance of discordant ischemia information between quantitative and qualitative parameters is unclear.
Methods:
This retrospective, cohort study analyzed 256 Rb-82 stress-rest PET/CT studies. Global MBF and myocardial flow reserve (MFR) were estimated in absolute units for quantitative results and sum-stress and difference scores were used for qualitative results. Four groups of patients were evaluated based on a specific definition of concordant and discordant quantitative and qualitative results.
Results:
31% of cases demonstrated discordance. Factors associated with microvascular disease were more common in the groups with abnormal quantitative results, regardless of the qualitative findings. Patients with concordant abnormal results had a significantly increased risk of myocardial infarction, heart failure, percutaneous intervention, and all-cause-mortality at 1 year compared to patients with concordant normal results. In patients with discordant results of abnormal quantitative and normal qualitative findings, there was a higher prevalence of heart failure than in controls (12.5% vs 0%, p = 0.01).
Conclusions:
Discordance in qualitative and quantitative ischemia measures from PET is common, and further study is needed to clarify its prognostic implications. Moreover, quantitative estimation of MBF and MFR appears to add value to qualitative visual interpretation by supporting qualitative findings when results are concordant. Abnormal quantitative findings, regardless of concordance or discordance with qualitative findings, occurred in patients with risk factors associated with diffuse disease and with increased risk of heart failure admission.
... In addition, clinicians have noted a lateral wall defect with ammonia that is artifactual and unexplained. 10 In total, N13-ammonia provides an important alternative to rubidium-82 with both strengths and weaknesses. Having two available tracers in the PET environment offers more opportunities for users. ...
... Since ECPA is an unexpected and life-threatening condition, developing a diagnostic tool amongst suspicious young and healthy patients is demanded. Positron emission-computed tomography (PET/CT) is a novel modality in cardiology that is superior to other tools in evaluating cardiac perfusion in combination with assessment of epicardial coronary arteries' anatomy and inflammation of vessel wall in patients who are suspected of having CAD [9]. It can yield information about the infiltrative cells in the vessels and myocardium in early stages of cardiac inflammatory disease, as it has a diagnostic role in other vasculitis, for instance Wegener's granulomatosis or Churg-Strauss Syndrome and cardiac sarcoidosis. ...
Eosinophilic coronary periarteritis (ECPA) is a poorly studied type of coronary arteritis. It causes myocardial ischemia and most cases are diagnosed at autopsy. We report the case of a 35-year-old woman who presented with sudden unexpected cardiac arrest and was brought to the emergency ward. Cardiopulmonary resuscitation was started by ambulance paramedic. On arrival, the patient was transferred to the catheterization laboratory due to sudden aborted cardiac death. The angiography was performed and dissection of the left main coronary artery, extended to the left anterior descending artery was detected. Pathological study confirmed ECPA. It appears that young and healthy patients with a history of intermittent vasospastic angina should be evaluated for ECPA.
<Learning objective: Young and healthy patients with a history of intermittent Prinzmetal vasospastic angina should be evaluated for eosinophilic coronary periarteritis (ECPA) prior to sudden cardiac death. Since ECPA is an unexpected and life-threatening condition, developing a diagnostic tool amongst suspicious young and healthy patients is demanded. Positron emission tomography–computed tomography might be an interesting tool, since it can detect infiltrative cells in early stages of cardiac inflammatory disease.
... There, they highly recommend the use of non-invasive imaging techniques to evaluate the eligibility of revascularization [93] by assessing two important physiological parameters, the myocardial blood flow (MBF) and the myocardial viability. Several non-invasive imaging techniques can perform these assessments, including: single photon emission computed tomography (SPECT) [140,216], cardiac magnetic resonance (CMR) [62], echocardiography (EC) [121,145], or positron emission tomography (PET) [43,46,136,154,190]. ...
... Nevertheless, the central goal nowadays has shifted from diagnosing obstructive CAD to detecting patients who are at risk for developing CAD or who already have preclinical (although not obstructive) CAD. This early diagnosis of patients at risk may translate into the ability to prevent, halt progression of promote regression of atherosclerosis before it becomes clinically overt [46]. ...
--Introduction--
According to the World Health Organization, cardiovascular diseases (CVDs) are the first cause of death globally. CVDs are a cluster of disorders that involve heart and blood vessels. Among them, coronary artery disease (CAD) is the most important disease in terms of mortality, causing more than 50% of the annual deaths. Over the last decades, many recognized international organisms, such as the World Health Organization and the American College of Cardiology have done great efforts to reduce the mortality and morbidity of CAD. In this line, accurate diagnosis and cost-effective management of CAD have revealed to be of utmost importance.
Several imaging techniques are currently used in the clinical practice to provide a diagnosis and clinical assessment of the disease. Among them, Positron Emission Tomography (PET) is considered to be the “gold standard” for noninvasive assessment of myocardial perfusion and viability, the two most relevant physiological parameters used to diagnose and manage patients with known or suspected CAD.
However, despite its unquestioned diagnostic value, PET still faces several difficulties to- wards its expansion as a clinical tool utilized worldwide. This is due to factors such as the high cost of the scanners and the extremely low availability of the radiopharmaceuticals required to perform the tests (mainly due to their cyclotron-based production pathway and their short half-lives).
--Objectives--
In this thesis we addressed some of those difficulties by exploring new
labeled radiotracer ( Ga-DOTA). Ga can be obtained from a Ge/ Ga generator and has a half-life of 68 minutes, which makes it a convenient candidate for its widespread clinical use.
We proposed and validated the use of 68Ga-DOTA as a radiotracer for assessment of my- ocardial blood flow (MBF), myocardial viability and pulmonary blood flow (PBF). Additionally, we introduced a new methodology to perform a PET scan in which this tracer could be co- injected simultaneously with some other radiotracers such as 18FDG (multi-tracer PET). Lastly, we developed an automatic detector able to perform blood spectroscopy analysis, which offered the possibility to perform multi-tracer PET with minimal human intervention.
--Methods--
To test the capability of 68Ga-DOTA to measure MBF, viability and PBF, different groups of Large White pigs underwent PET/CT scans using 68Ga-DOTA as the injected radiotracer. For PBF studies, a group of healthy pigs (n = 4) were scanned under rest conditions. For MBF studies, a group of 8 pigs were scanned under rest and pharmacologically-induced stress in order to perform rest/stress tests, as it is done for humans in clinical routine. Additionally, a group of 5 pigs were scanned 7 days after the induction of a myocardial infarction (MI) to assess viability and MBF in a MI model.
MBF, extracellular volume fraction (ECV, for viability assessment) and PBF maps were obtained after fitting the dynamic PET images to the corresponding pharmacokinetic model followed by 68Ga-DOTA in each tissue under study. Global and regional perfusion maps for the myocardial tissue (MBF) and lungs (PBF) were obtained. For validation purposes, the “gold- standard” technique used in tissue perfusion quantification (fluorescent-labeled microspheres (MS)) was simultaneosly performed along with the PET/CT scans.
The blood sampling spectroscopic methodology was evaluated and calibrated in vitro using different 68Ga/18F mixtures. Then, it was tested in pigs (n = 3) injected with 68Ga-DOTA and 18FDG in the same acquisition. The activity concentration of each radiotracer in myocardial tissue was subsequently measured ex vivo.
The automatic blood sampling detector was built from scratch and characterized using a catheter filled with different 68Ga/18F mixtures. Finally, it was additionally evaluated in vivo in n = 3 pigs under conditions resembling to those encountered in clinical routine.
--Results--
Regarding MBF quantification and validation with 68Ga-DOTA-PET, a strong correlation (r = 0.91) between MBF measured with PET and MS was obtained (slope = 0.96 ± 0.10, y-intercept = 0.11 ± 0.19 ml·min−1·g−1). For the myocardial infarction model, MBF values obtained with 68Ga-DOTA-PET in the infarcted area (LAD, left anterior descendant) were significantly reduced in comparison to remote ones LCX (left circumflex artery, p < 0.0001) and RCA (right coronary artery, p < 0.0001). In addition, 68Ga-DOTA-PET detected a significant ECV increase in the infarcted area (p < 0.0001).
The correlation evaluation between 68Ga-DOTA-PET and MS as a PBF radiotracer also showed a good and significant correlation (r = 0.74, p < 0.0001).
The gamma spectroscopic analysis on blood samples proposed for multi-tracer PET imag- ing was also succesfully validated, showing a correlation of r = 0.95 (p < 0.0001) for 18FDG concentration in myocardium measured with multi-tracer PET and by ex vivo validation.
The blood sampling detector was able to measure the arterial input function in pigs in an experimental setup under realistic conditions.
Discussion and conclusions
68Ga-DOTA-PET allowed accurate non-invasive assessment of MBF and ECV in pigs with my- ocardial infarction and under rest-stress conditions. This technique could provide wide access
As for multi-tracer PET imaging, the proposed methodology allowed explicit measurement of separate arterial input functions, offering very similar results to those obtained as a reference from the ex vivo analysis of the tissue under evaluation.
Finally, a novel blood sampling device was developed and characterized, showing perfor- mance parameters similar to other devices in the literature. Noteworthy, this detector has the additional and unique feature of allowing us to perform multi-tracer PET by means of a gamma spectroscopic analysis of the blood flowing between its detection blocks.
All the results summarized in this abstract may contribute to spread the use of PET in clinical routine, either by the clinical use of 68Ga-DOTA as an inexpensive but accurate radio- tracer for MBF, PBF or viability assessment, or by the implementation of multi-tracer PET, which could lead to cost reduction of PET examinations by shortening the scanning time and eliminating misalignment inaccuracies. This multi-tracer PET methodology could also be safely implemented using our proposed automated device that permits to perform the gamma spectro- scopic analysis on blood samples with minimal human intervention.
... Hybrid PET-CT scanners allow concurrent evaluation of myocardial perfusion and anatomic assessment of the epicardial coronary arteries offering great potential for better risk stratification and treatment. However, further studies are needed to validate the prognostic value and cost effectiveness of PET [9,62]. ...
Autoimmune rheumatic diseases (ARDs) affect 8% of the population, and approximately 78% of them are women. Cardiovascular disease (CVD) in ARDs encompasses different pathophysiologic processes, such as endothelial dysfunction, myocardial/vascular inflammation and accelerated atherosclerosis with silent clinical presentation, leading to heart failure (HF), usually with preserved ejection fraction. Echocardiography and cardiovascular magnetic resonance (CMR) are the two most commonly used noninvasive imaging modalities for the evaluation of HF in patients with ARDs. Echocardiography currently represents the main diagnostic tool for cardiac imaging in clinical practice. However, the demand for more efficient and prompt diagnostic and therapeutic approach in this specific population necessitates the implementation of modalities capable of providing a more detailed and quantified information from the point of tissue characterization. Furthermore, echocardiography is an operator and acoustic window depended modality, with relatively low reproducibility and unable to perform tissue characterization. CMR is a noninvasive modality without radiation that can give reproducible and operator-independent information about both myocardial function and tissue characterization. By providing quantification of oedema, stress perfusion defects and fibrosis, CMR can diagnose myocardial inflammation, micro–macro-vascular myocardial ischemia and replacement or diffuse fibrosis, respectively. Tissue characterization allows for moving beyond the cardiac function to the assessment of intra- and inter-cellular alterations and promotes the development of personalized cardiac and anti-rheumatic treatment in ARDs with HF. ARDs are mainly female diseases. Cardiac involvement leading in HF is not unusual in ARDs and remains the main cause of death. Noninvasive, nonradiating imaging modalities such as echocardiography and CMR represent the main diagnostic tools. Specifically, echocardiography represents the first diagnostic approach; however, it is CMR that gives information about the pathophysiologic background behind HF in ARDs.
