Cardiovascular PET-CT
Yi-Hwa Liu, Albert J. Sinusas in Hybrid Imaging in Cardiovascular Medicine, 2017
Positron emission tomography (PET) is the leading tool in nuclear cardiology for noninvasive assessment of molecular function. Images are obtained via detection of positrons emitted from the decay of an injected radiotracer. Radiotracers are either short-lived isotopes themselves, such as 82Rb, or isotopes that have been incorporated into biological or drug compounds, such as 18F-fluoro-deoxyglucose or 11C-methyl-losartan, respectively. The amount of tracer injected is low enough such that it does not affect the physiological process being imaged. Most isotopes are produced in a cyclotron and undergo radiochemical synthesis to be incorporated into a tracer molecule, requiring an onsite or local cyclotron due to the short half-lives. There has been a shift toward simpler and more cost-effective onsite alternatives, such as the generator-produced tracer 82Rb. Some of the most common clinical and research-based cardiac PET tracers, their characteristics, applications, and the associated imaging protocols are listed in Table 2.1 (Zober et al. 2006; Thackeray and Bengel 2013; Danad, Raijimakers, and Knaapen 2013).
Non-invasive cardiac imaging for the interventionist
Ever D. Grech in Practical Interventional Cardiology, 2017
Cardiac PET is a nuclear medicine technique using intravenous injection of a radiotracer for the evaluation of perfusion and viability. PET can be used to quantify both perfusion and metabolism as well as determine myocardial viability. PET requires the use of cyclotron-produced positron-emitting isotopes (e.g. 82rubidium, 13N-ammonia). Although there is less evidence than for MPS, meta-analyses have suggested that PET has higher sensitivity for the detection of CAD than MPS, including in women and obese patients,31,32 likely due to its higher spatial resolution. The ESC guidelines for the management of stable chest pain include PET as an non-invasive stress imaging option.4 PET is the gold standard test for the non-invasive quantification of myocardial blood flow, allowing the detection of microvascular disease.
Non-invasive assessment of ischaemic heart disease
John Edward Boland, David W. M. Muller in Interventional Cardiology and Cardiac Catheterisation, 2019
Cardiac PET viability assessment may occur in two parts, by combining perfusion assessment using radionuclides Nitrogen-13 labelled ammonia (13NH3) or rhubidium-82, and by metabolic assessment using Fluorodeoxyglucose-18 (FDG-18). In some centres, perfusion assessment may take place using SPECT techniques where FDG is taken up by metabolically active tissue. This generally indicates preserved myocardial viability, but the specific pattern of perfusion and metabolic function provided by PET may indicate various pathophysiologies: Perfusion-metabolism mismatch with reduced myocardial perfusion and contractile function in the setting of preserved FDG uptake indicating viable ‘hibernating’ myocardium.Regions of normal perfusion and normal metabolism in dysfunctional segments (may represent myocardial stunning, or remodelling).Reduction in both perfusion and metabolism (myocardial scar).Reversed-mismatch whereby there is normal perfusion but reduced FDG-18 uptake. This can occur in diabetes mellitus, but also following revascularisation early after myocardial infarction and in left bundle branch block.15
Non-invasive imaging techniques to assess myocardial perfusion
Published in Expert Review of Medical Devices, 2020
Olivier Villemain, Jérôme Baranger, Zakaria Jalal, Christopher Lam, Jérémie Calais, Mathieu Pernot, Barbara Cifra, Mark K. Friedberg, Luc Mertens
Ultimately, it seems intuitive to say that the next generation of imaging for myocardial perfusion analysis will be hybrid (or fusion) techniques combining several techniques and combining their strengths. The CT-SPECT combination (Figure 5) is one possible example, as is the Ultrasound-PET combination. Since 2010, hybrid PET/MRI using sequential and integrated scanner platforms has been available, with hybrid cardiac PET/MR imaging protocols increasingly incorporated into clinical workflows. Given the range of complementary information provided by each method, the use of hybrid PET/MRI may be justified and beneficial in particular clinical settings for the evaluation of different disease entities. Indeed, as summarized in this Review paper, each technique has its inherent limitations in the underlying physics. But being able to combine the advantages of each would allow research and medical teams to go further in the analysis of myocardial perfusion. Through the development of other technologies, such as machine learning, automatic image analysis, or potential robotization (for the automatic performance of echocardiography), the association and combination of imaging techniques will become more accessible and reliable.
Cardiac sarcoidosis – an expert review for the chest physician
Published in Expert Review of Respiratory Medicine, 2019
Jamie S. Y. Ho, Edwin R. Chilvers, Muhunthan Thillai
Experts from three independent organisations have developed consensus pathways for diagnosis of CS in the absence of direct EMB histological evidence (Table 4). As they do not have prognostic evidence regarding clinical use, it is unclear which of these is more accurate in diagnosing CS. The original 1993 JMHW criteria are reported to miss almost half of those diagnosed with the 2006 update, some of whom will go on to experience malignant VT [83]. All of the guidelines involve clinical presentations of reduced LVEF, conduction disturbances, ventricular arrhythmias, as well as positive gallium scan, LGE-CMR and cardiac PET uptake. These have been combined to propose a simple diagnostic pathway, which can be used to determine the need for advanced cardiac testing in suspected CS (Figure 4).
Quantification of cardiac amyloid with [18F]Flutemetamol in patients with V30M hereditary transthyretin amyloidosis
Published in Amyloid, 2020
Sofia Möckelind, Jan Axelsson, Björn Pilebro, Per Lindqvist, Ole B. Suhr, Torbjörn Sundström
The patients with SUV below the cut-off raise some concerns regarding the sensitivity of the method. One patient had type A fibril proven by fat pad biopsy, cardiac hypertrophy (end-diastolic intraventricular septum thickness 18 mm), and was the only patient in this study with a positive DPD-scintigraphy. The low PET-tracer uptake is not surprising, considering previous reported studies with cardiac PET amyloid imaging, where type A fibril pattern had a significantly lower uptake than those with the type B fibril pattern [16,22]. One explanation might be that the tracer has lower affinity for type A amyloid fibrils than type B, as is the case in histopathological examination by Congo red. Another might be that patients with type A fibrils have decreased perfusion of their amyloid deposits since the deposits are more massive and found in large nodules [34]. It is thus tempting to speculate that the availability of the amyloid to the blood born tracer is much lower in patients with type A fibril deposits.
Related Knowledge Centers
- Coronary Artery Disease
- Positron Emission Tomography
- Metabolism
- Cardiovascular Disease
- Medical Imaging
- Intravenous Therapy
- Radioactive Tracer
- Rubidium-82
- Nitrogen-13
- Isotopes of Oxygen