Excerpt

The obesity epidemic has impacted upon all aspects of modern health care delivery, and presents unique challenges for the accurate diagnosis and management of patients with suspected coronary artery disease (CAD). The prevalence of extreme obesity, defined as BMI ≥40 kg/m², has increased from approximately 1% to 6% of the adult US population from the 1960s to 2010,1 and extremely obese patients represent an increasing proportion of patients referred for myocardial perfusion imaging (MPI). From a diagnostic perspective, this patient subgroup embodies an important, modern conundrum. On the one hand, extremely obese patients are at increased cardiovascular risk over their lifespan as a result of chronic metabolic disease.2 They are also less likely to exercise or to be functionally active, and as such, may not manifest cardiovascular symptoms until the later stages of disease, possibly warranting a high index of suspicion for evaluation. On the other hand, extremely obese patients are also less likely to undergo an evaluation of sufficient diagnostic quality, no matter the imaging modality utilized.3 In radionuclide cardiac perfusion imaging, specifically with single photon emission tomography (SPECT), nonuniform attenuation of radiotracer counts by excess adipose tissue may result in apparent perfusion defects and false positive studies, which may lead to unnecessary referral for invasive evaluations with ensuing risk of complications. As such, modern technologies with increased sensitivity and specificity for diagnosing CAD are needed to meet the modern challenge of adequately caring for these patients. …