The clinical role of positron emission tomography in management of the cardiac patient.
Positron emission tomography (PET) is the most advanced scintigraphic imaging technique developed for in-vivo assessment of cardiac physiology and biochemistry. The currently available PET technology allows the measurement of regional tracer activity with high spatial and temporal resolution. Several radiopharmaceuticals have been introduced to study myocardial perfusion enabling accurate diagnosis and localization of coronary artery disease (CAD). Assessing myocardial blood flow at rest and under stress conditions and calculating (regional) coronary flow reserve by N-13 ammonia, Rb-82 or 0-15 water PET is the most sensitive means to detect any abnormal vasoreactivity which is already found at very early stages of the atherosclerotic process before any angiographic or clinical evidence of CAD. Flow tracers provide also quantitative information on the hemodynamic effects of any local, invasive (angioplasty) or systemic (risk factor modification) intervention. Metabolic imaging with F-18 deoxyglucose (FDG) PET represents currently the gold-standard for tissue viability assessment with well-validated information about the presence and extent of viable myocardium. The prognostic information of metabolic imaging extends to (preoperative) risk stratification in patients with congestive heart failure and facilitates the decision making between revascularization or conservative management. FDG has been also used in combination with SPECT providing comparable physiologic and pathophysiologic information but without need for the expensive and rarely available imaging technology of PET. More recently, newer tracers such as radiolabeled catecholamine analogs allowed the evaluation of cardiac autonomic innervation in a variety of cardiac diseases with involvement of neuronal innervation. C-11 hydroxyephedrine (HED) enabled imaging of alterations in neuronal innervation in diabetes, congestive heart failure and after heart transplantation. The unique functional and prognostic potential provided by PET imaging together with an expected easier access to this technology with better availability of lower cost instrumentation should raise its clinical acceptance in the near future.
Pirich
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Nuklearmedizinische Klinik und Poliklinik, Techische Universität München, Klinikum Rechts der Isar, Germany.
Schwaiger
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D003326:Coronary Circulation; D005947:Glucose; D006321:Heart / Q000000981:diagnostic imaging* / Q000294:innervation / Q000503:physiopathology; D006331:Heart Diseases / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000503:physiopathology; D006801:Humans; D009206:Myocardium / Q000378:metabolism; D019275:Radiopharmaceuticals; D013564:Sympathetic Nervous System / Q000000981:diagnostic imaging; D014022:Tissue Survival; D014055:Tomography, Emission-Computed / Q000379:methods
D019275:Radiopharmaceuticals; D005947:Glucose