Myo-Myo: Yes, papa. Eating sugar? No, papa!

Abstract

Each year 295,000 hospital cardiac arrests occur in theUSA [1], with a median survival rate of 7.9%. Only 33% ofthese cardiac arrest patients have symptoms earlier than 1 hbefore death. These sobering statistics emphasize the urgentneed to develop a reliable method to identify patients athigh risk for a fatal cardiac event. Although primaryprevention is a successful strategy in a population, fatefulevents continue to occur [2] in a sizable proportion ofsubjects treated with the best of medical regimens. To offerthe most effective care may require identification andpossibly local treatment of high-risk coronary lesions ineach patient.High-risk plaque includes a voluminous necrotic core,containing lipids, oxidized lipids, numerous dead cells, andactivated macrophages [3, 4]. The necrotic core is coveredby an attenuated and an inflamed fibrous cap. Identifyingthe thin cap is only possible by invasive intravascularimaging. The necrotic core, however, can be assessed bycomputed tomography angiography [5, 6]. The necroticcore appears as a low-attenuation or low-density area onCT and often induces expansive (or outward) remodeling ofthe affected vascular segment. On the other hand,inflammation may be amenable to molecular imagingstrategies [7, 8]. Since the intense metabolic demand ofthe lesional macrophages is met by exogenous glucosediffusing into the lesion from the blood, it has beenproposed that positron-labeled fluorodeoxyglucose (FDG)should concentrate at the site of inflammation, allowingvisualization on positron emission tomography (PET)images [9].FDG PET/CT images in cancer patients often showmultiple focal sites of uptake in the aorta [10]. In patientsundergoing carotid endarterectomy, FDG PET scans con-firmed that focal tracer uptake in the carotid arteries ofhumans is due to localization in macrophages [11]. Inprospective investigations, FDG uptake occurred selectivelyin symptomatic carotid vascular disease [12] and wassignificantly reduced in response to statin treatment [13].On the other hand, FDG uptake is seldom seen in thecoronary vasculature [10, 14]. There are several factorslimiting visualization of lesions in the coronary arteriesincluding: physiologic FDG uptake in the myocardium,limiting the contrast in the lesion due to high background;small size of coronary lesions (often less than 2 mm