PET Imaging of Post-infarct Myocardial Inflammation.

Funder: Department of HealthPurpose of reviewTo examine the use of positron emission tomography (PET) for imaging post-infarct myocardial inflammation and repair.Recent findingsDysregulated immune responses after myocardial infarction are associated with adverse cardiac remodelling and an increased likelihood of ischaemic heart failure. PET imaging utilising novel tracers can be applied to visualise different components of the post-infarction inflammatory and repair processes. This approach could offer unique pathophysiological insights that could prove useful for the identification and risk-stratification of individuals who would ultimately benefit most from emerging immune-modulating therapies. PET imaging could also bridge the clinical translational gap as a surrogate measure of drug efficacy in early-stage clinical trials in patients with myocardial infarction. The use of hybrid PET/MR imaging, in particular, offers the additional advantage of simultaneous in vivo molecular imaging and detailed assessment of myocardial function, viability and tissue characterisation. Further research is needed to realise the true clinical translational value of PET imaging after myocardial infarction

The vanishing atrial mass.

HEFCEThis is the final version of the article. It first appeared from Oxford University Press via https://doi.org10.1093/ehjci/jew12

An unusual finding in a 57-year-old woman with new onset hypertension and a diastolic murmur.

CLINICAL INTRODUCTION: A 57-year-old woman presented to our clinic with breathlessness brought on while walking uphill. She had been recently diagnosed with systemic hypertension. There was no known family history of cardiac disease, or prior smoking habit. On examination, pulse was 73 bpm and blood pressure 155/73 mm Hg, which was asymmetrical in her arms. Auscultation revealed a readily audible early diastolic murmur in the aortic area and bilateral subclavian bruits. ECG showed sinus rhythm with no abnormality. Transthoracic echocardiography demonstrated mild-to-moderate aortic regurgitation, and normal left ventricular size and function. The ascending aorta was mildly dilated (41 mm), with para-aortic thickening noted. Owing to the abnormal appearance of the aortic wall, cardiac MRI, and subsequently 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) scan was performed (figure 1). QUESTION: Which complication of the underlying disease is evident in figure 1, panel C? Aortic aneurysmAortic dissectionAortic thrombusCoronary artery aneurysmCoronary sinus fistula

Noninvasive Molecular Imaging of Disease Activity in Atherosclerosis.

Major focus has been placed on the identification of vulnerable plaques as a means of improving the prediction of myocardial infarction. However, this strategy has recently been questioned on the basis that the majority of these individual coronary lesions do not in fact go on to cause clinical events. Attention is, therefore, shifting to alternative imaging modalities that might provide a more complete pan-coronary assessment of the atherosclerotic disease process. These include markers of disease activity with the potential to discriminate between patients with stable burnt-out disease that is no longer metabolically active and those with active atheroma, faster disease progression, and increased risk of infarction. This review will examine how novel molecular imaging approaches can provide such assessments, focusing on inflammation and microcalcification activity, the importance of these processes to coronary atherosclerosis, and the advantages and challenges posed by these techniques.M.R.D and D.E.N are supported by the British Heart Foundation (CH/09/002 to D.E.N., FS/14/78/31020 to M.R.D). M.R.D is the recipient of the Sir Jules Thorn Biomedical Research Award 2015 (M.R.D.) E.A. research is supported by R01HL 114805 and R01HL 109506.This is the final version of the article. It first appeared from Lippincott, Williams & Wilkins via http://dx.doi.org/10.1161/CIRCRESAHA.116.30797

Novel Positron Emission Tomography Tracers for Imaging Vascular Inflammation

Abstract: Purpose of Review: To provide a focused update on recent advances in positron emission tomography (PET) imaging in vascular inflammatory diseases and consider future directions in the field. Recent Findings: While PET imaging with 18F-fluorodeoxyglucose (FDG) can provide a useful marker of disease activity in several vascular inflammatory diseases, including atherosclerosis and large-vessel vasculitis, this tracer lacks inflammatory cell specificity and is not a practical solution for imaging the coronary vasculature because of avid background myocardial signal. To overcome these limitations, research is ongoing to identify novel PET tracers that can more accurately track individual components of vascular immune responses. Use of these novel PET tracers could lead to a better understanding of underlying disease mechanisms and help inform the identification and stratification of patients for newly emerging immune-modulatory therapies. Summary: Future research is needed to realise the true clinical translational value of PET imaging in vascular inflammatory diseases

PET Imaging of Atherosclerotic Disease: Advancing Plaque Assessment from Anatomy to Pathophysiology.

Atherosclerosis is a leading cause of morbidity and mortality. It is now widely recognized that the disease is more than simply a flow-limiting process and that the atheromatous plaque represents a nidus for inflammation with a consequent risk of plaque rupture and atherothrombosis, leading to myocardial infarction or stroke. However, widely used conventional clinical imaging techniques remain anatomically focused, assessing only the degree of arterial stenosis caused by plaques. Positron emission tomography (PET) has allowed the metabolic processes within the plaque to be detected and quantified directly. The increasing armory of radiotracers has facilitated the imaging of distinct metabolic aspects of atherogenesis and plaque destabilization, including macrophage-mediated inflammatory change, hypoxia, and microcalcification. This imaging modality has not only furthered our understanding of the disease process in vivo with new insights into mechanisms but has also been utilized as a non-invasive endpoint measure in the development of novel treatments for atherosclerotic disease. This review provides grounding in the principles of PET imaging of atherosclerosis, the radioligands in use and in development, its research and clinical applications, and future developments for the field.NRE is supported by a research training fellowship from The Dunhill Medical Trust [grant number RTF44/0114]. JMT is supported by a Wellcome Trust research training fellowship (104492/Z/ 14/Z). MMC is part-supported by the Royal College of Surgeons of England Fellowship Program. JHFR is part-supported by the HEFCE, the NIHR Cambridge Biomedical Research Centre, the British Heart Foundation, and the Wellcome Trus

Imaging Atherosclerosis.

Advances in atherosclerosis imaging technology and research have provided a range of diagnostic tools to characterize high-risk plaque in vivo; however, these important vascular imaging methods additionally promise great scientific and translational applications beyond this quest. When combined with conventional anatomic- and hemodynamic-based assessments of disease severity, cross-sectional multimodal imaging incorporating molecular probes and other novel noninvasive techniques can add detailed interrogation of plaque composition, activity, and overall disease burden. In the catheterization laboratory, intravascular imaging provides unparalleled access to the world beneath the plaque surface, allowing tissue characterization and measurement of cap thickness with micrometer spatial resolution. Atherosclerosis imaging captures key data that reveal snapshots into underlying biology, which can test our understanding of fundamental research questions and shape our approach toward patient management. Imaging can also be used to quantify response to therapeutic interventions and ultimately help predict cardiovascular risk. Although there are undeniable barriers to clinical translation, many of these hold-ups might soon be surpassed by rapidly evolving innovations to improve image acquisition, coregistration, motion correction, and reduce radiation exposure. This article provides a comprehensive review of current and experimental atherosclerosis imaging methods and their uses in research and potential for translation to the clinic.J.M.T. is supported by a Wellcome Trust research training fellowship (104492/Z/14/Z). M.D is supported by the British Heart Foundation (FS/14/78/31020). N.R.E. is supported by a research training fellowship from the Dunhill Medical Trust (RTF44/0114). A.J.B. is supported by the British Heart Foundation. J.H.F.R. is part-supported by the HEFCE, the NIHR Cambridge Biomedical Research Centre, the British Heart Foundation, and the Wellcome Trust.This is the final version of the article. It first appeared from the American Heart Association via http://dx.doi.org/10.1161/CIRCRESAHA.115.30624

68Ga-DOTATATE PET Identifies Residual Myocardial Inflammation and Bone Marrow Activation After Myocardial Infarction.

Myocardial infarction (MI) healing occurs in two phases: first an inflammatory phase, where clearance of necrotic debris occurs, followed by a reparative phase characterized by angiogenesis, granulation tissue formation and attempts to repair the extracellular matrix. While efficient healing relies on co-ordinated mobilization of monocytes to the damaged myocardium, with resolution of the acute inflammatory response by ~10-14 days, excessive inflammation impairs myocardial salvage and promotes adverse cardiac remodelling