PET should not replace routine SPECT MPS for the assessment of patients with known or suspected CAD

Excerpt

Single-photon emission computed tomography (SPECT) myocardial perfusion scintigraphy (MPS) has been widely available for decades and has been extensively validated for the diagnosis and risk assessment of patients with known or suspected coronary artery disease (CAD).1,2 It has a class I indication in both US and European guidelines.3,4 The major part of this validation has been against invasive coronary angiography, largely reflecting the anatomical thinking historically prevalent in cardiology practice. The sensitivity and normalcy of SPECT MPS for the detection of angiographically defined significant CAD is 85%-90% and 89%, respectively,2 although lower figures are not uncommon in studies subject to post-test referral bias or where the images are interpreted in the absence of the usual clinical information. When compared with invasive coronary angiography with fractional flow reserve, sensitivity is maintained but specificity is lower (61%).5 Regardless, the prognostic value of normal MPS is well recognized, with an annual coronary event rate <1%.6 Although such patients may be further stratified by anatomical tests such as invasive or CT coronary angiography, patients with a normal study can usually be reassured without the need for further testing. Those with abnormal MPS have a seven-fold higher annual risk of myocardial infarction and death compared with those with normal studies7 and the coronary event rate increases with ischemic burden.6

…