PET and SPECT in cardiovascular molecular imaging

Abstract

The current focus of cardiovascular medicine is on early detection and prevention of disease, to control the escalating costs of health care. To achieve this goal, novel imaging approaches that allow for early detection of disease and risk stratification are needed. Traditionally, the diagnosis, monitoring, and prognostication of cardiovascular disease were based on techniques that measured changes in metabolism, blood flow, and biological function. Molecular imaging is emerging as a new tool for the noninvasive detection of biological processes that can differentiate and characterize tissues before manifestation of gross anatomical features or physiological consequences. Leading the way are techniques involving high-sensitivity radiotracers that could revolutionize current diagnostic paradigms. This Review provides an overview of selected molecular-based single photon emission CT (SPECT) and PET imaging strategies for the evaluation of cardiovascular disease-including the evaluation of myocardial metabolism and neurohumoral activity of the heart-and potential future targeted methods of evaluating critical molecular processes, such as atherosclerosis, ventricular remodeling after myocardial infarction, and ischemia-associated angiogenesis.

Imaging Strategies for Tissue Engineering Applications

“…However, although MRI is generally a superior imaging method in many aspects (possibly to be used for molecular imaging as well), it is not the best tool to monitor molecular interactions compared to other molecular imaging modalities mainly due to low sensitivity and limited molecular probes. 28,38 Because MRI has the superior ability of distinguishing soft tissue contrast, MRI can visualize and assess tissueengineered constructs without exogenous contrast agents in vitro and in vivo. Several in vitro MRI studies have demonstrated the evaluation of tissue-engineered constructs, such as assessing the composition of bladder acellular matrixbased scaffolds using measured MR relaxation times (T 1 , T 2 ) and diffusion coefficients.…”

“…10, 28 The fundamental principle underlying PET/SPECT imaging is the use of radioactive agents, which can localize in specific organs or tissue on the basis of their biochemical or physiological properties. Because specific chemicals of biological interest can be radiolabeled, nuclear imaging has the potential to monitor functional processes.…”

Multiple Target-Specific Molecular Agents for Detection and Image Analysis of Breast Cancer Characteristics in Mice

“…Both PET and SPECT can detect low doses of injected tracers and provide 3D data [29]. Optical imaging is a rapidly growing preclinical molecular imaging modality that uses the same targets as nuclear molecular imaging, but replaces radioactive reporters with optical reporters.…”

In Vivo Imaging of Neurovascular Remodeling After Stroke

“…43 The potential for detection of angiogenesis after stroke has been demonstrated by Cai et al, 44 who used a specific PET radiopharmaceutical to measure expression of vascular endothelial growth factor receptors in rats after MCA occlusion. Tracer uptake in the lesion was elevated at day 2, peaked at day 9, and normalized at day 23, and corresponded spatially with areas where angiogenesis was detected with postmortem histology ( Figure III).…”