Positron Emission Tomography in the Routine Management of Coronary Artery Disease

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With generator-produced Rb-82 having a half-life of 75 seconds, 40 to 50 mCi have to be infused quickly intravenously. Data acquisition has to be completed in five minutes with high count rates early in acquisition, 2M to 3M cps. Consequently, random coincidences, dead time and scatter are high with potentially high noise and poor signal to noise ratio. In the authorÔÇÖs experience of reducing noise and acquiring sufficiently high true counts, 2-D imaging with long extended septa, filtered back projection reconstruction and a scanner capable of high true count rate are essential for the advanced cold area imaging demonstrated in these examples. Acquisition of 3-D image and ordered-subset expectation maximization (OSEM) reconstruction techniques are not satisfactory for high-quality cardiac perfusion imaging using Rb-82.

Misregistration of attenuation and emission images is common in cardiac PET imaging, and causes artifactual defects in 20% of patients, predicted by diaphragmatic displacement, body mass index, and heart size. Software for visually optimizing co-registration of attenuation and emission images is essential for eliminating artifacts. Recognizing and correcting these misregistration artifacts are essential for reliably identifying mild perfusion defects of early non-obstructive coronary atherosclerosis as the basis for intense lifestyle and pharmacologic treatment.

Summary

Cardiac PET, conducted correctly with attention to technical details, provides definitive non-invasive assessment of early or advanced coronary atherosclerosis as the basis for invasive procedures or lifelong intense risk factor management, demonstrates progression or regression of disease, predicts clinical outcomes, and may serve as the primary basis for managing CAD. Ôûá

This article can be found with references in the Reference Section on the website supporting this business briefing (www.touchcardiology.com).

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