Clinical Myocardial Perfusion PET/CT

Abstract

The field of nuclear cardiology is witnessing growing interest in the use of cardiac PET for the evaluation of patients with coronary artery disease (CAD). The available evidence suggests that myocardial perfusion PET provides an accurate means for diagnosing obstructive CAD, which appears superior to SPECT especially in the obese and in those undergoing pharmacologic stress. The ability to record changes in left ventricular function from rest to peak stress and to quantify myocardial perfusion (in mL/min/g of tissue) provides an added advantage over SPECT for evaluating multivessel CAD. There is growing and consistent evidence that gated myocardial perfusion PET also provides clinically useful risk stratification. Although the introduction of hybrid PET/CT technology offers the exciting possibility of assessing the extent of anatomic CAD (CT coronary angiography) and its functional consequences (ischemic burden) in the same setting, there are technical challenges in the implementation of CT-based transmission imaging for attenuation correction. Nonetheless, this integrated platform for assessing anatomy and biology offers a great potential for translating advances in molecularly targeted imaging into humans. PET has contributed significantly to advance our understanding of heart physiology and pathophysiology for .25 y. Initially, it emerged as a powerful investigative tool that allowed in vivo quantification of physiologic processes, including myocardial perfusion and metabolism, neuronal and receptor function, and, more recently, molecularly targeted oncologic imaging. Despite its success in research applications, the limited availability of this technology, its increased cost, and the limited data supporting its use and reimbursement have all contributed to the relatively limited clinical acceptance of this imaging technology. Fortunately, there are now clear signs that change is under way. Indeed, the exponential growth in the number of PET/CT systemsattributable primarily to the technology's widely accepted role in clinical oncology-along with the Food and Drug Administration's approval of PET radiopharmaceuticals for cardiac imaging, changes in reimbursement, and the increasing documentation of PET's clinical efficacy have all contributed to help advance its clinical role in cardiovascular medicine.The emergence of integrated PET/CT technology as the dominant configuration of clinical scanners also holds great promise for cardiac imaging as it provides a potential opportunity to delineate the anatomic extent and physiologic severity of coronary atherosclerosis in a single setting. However, the recent rapid growth of PET/CT is now opening a considerable gap between the most sophisticated users of the technology and those with a more limited knowledge base and fewer training opportunities; this includes cardiologists, as well as nuclear medicine specialists, and radiologists, who frequently lack clinical experience in performing and interpreting these cardiovascular procedures. The objective of this review ...

Low-dose 3D 82Rb PET

“…4 The estimated patient radiation doses have recently been revised down to 3.7 mSv for 82 Rb PET scans with 80 mCi total injected dose (stress ? rest) by more precise patient-specific calculations.…”

“…3 Most literature in cardiac PET imaging describes studies performed in 2D mode. 4 However, currently the users of new PET/CT equipment are unable to acquire images in 2D since almost all new scanners operate in 3D mode only and come without septa. Therefore, the optimal use of such 3D PET/CT for cardiac imaging and in particular for 82 Rb imaging is of great interest to the nuclear cardiology community.…”

Attenuation Correction Strategies for Positron Emission Tomography/Computed Tomography and 4-Dimensional Positron Emission Tomography/Computed Tomography

“…17 PET/ CT also plays an important role in biologically guided radiation therapy 18,19 and treatment response assessment. 20,21 Integration of functional PET data with anatomic CT data should be a standard in radiation therapy.…”

Is metal artefact reduction mandatory in cardiac PET/CT imaging in the presence of pacemaker and implantable cardioverter defibrillator leads?

“…With the advent of 64-slice and over CT subsystems combined with dedicated PET scanners, full clinical cardiac protocols are now possible including CT angiography and calcium score imaging as an adjunct to myocardial viability and perfusion imaging using dedicated radiotracers. Beyond the vast potential of combined cardiac anatomical and functional imaging on combined PET/CT scanners [3], PET data can be corrected for photon attenuation using corresponding CT images. However, CT images may exhibit streak artefacts if highdensity materials such as metals [4,5] and oral and intravenous contrast agents [6,7] were present resulting in erroneous interpretation of both viability and perfusion PET images in those cases with severe artefact.…”