Excerpt
In this issue of the
European Journal of Nuclear Medicine and Molecular Imaging, Flotats et al. [
1] report a striking improvement in image quality of myocardial perfusion studies with the use of
82Rb PET/CT as compared to conventional
99mTc-labelled SPECT/CT. When using PET/CT in concert with the positron-emitting myocardial perfusion tracer
82Rb, the improvement in image quality also manifested in a higher interpretative confidence and interreader agreement of
82Rb perfusion images than observed for
99mTc-labelled SPECT/CT. In particular, the current study is unique in that
82Rb PET/CT and
99mTc-labelled SPECT/CT were performed in the same patient with known or suspected coronary artery disease (CAD). Previous investigations commonly compared the sensitivity and specificity of cardiac PET versus SPECT perfusion imaging in the detection of flow-limiting epicardial lesions [
2]. For example, Go et al. [
3] showed sensitivity, specificity and accuracy of 95, 82 and 92 % for
82Rb PET and 79, 76 and 78 % for
201Tl SPECT for haemodynamically obstructive CAD lesions. Further, Stewart et al. [
4] reported that overall sensitivity, specificity and accuracy of
82Rb PET for detection of coronary artery lesions ≥50 % diameter stenosis were 84, 88 and 85 %, respectively. In comparison to this, the performance of
201Tl SPECT revealed a sensitivity of 84 % but a low specificity of 53 % and a diagnostic accuracy of 79 %. The commonly higher sensitivity in the identification of flow-limiting epicardial lesions with
82Rb PET as compared with SPECT imaging, either with
201Tl or
99mTc-labelled perfusion tracers, can be related to the higher spatial and contrast resolution of
82Rb PET, while the photon attenuation–free images of PET imaging may account for the relative increase in specificity [
2]. …