Stress myocardial perfusion tomoscintigraphy with cadmium-zinc-telluride cameras: comparison with conventional Anger cameras according to study protocol and anthropometric parameters

Results from stress myocardial perfusion imaging SPECT should be enhanced by new cadmium-zinc-telluride (CZT) cameras, although differences with results from conventional Anger cameras remain poorly known. This multicentric study was aimed at comparing results from CZT- and Anger-SPECT according to anthropometric parameters and study protocols. Methods. The study population comprised 276 patients (59 women, 61 obese subjects) referred to study protocols involving 201Tl (n=120) or 99mTc-Sestamibi injected at low dose at stress (99mTc-Low; stress/rest one-day protocol; n=110) or at high dose at stress (99mTc-High; rest/stress one-day or two-day protocol; n=46). Each Anger-SPECT was followed by a high-speed CZT-SPECT (2 to 4 min). CZT-SPECT images were reconstructed in conditions leading to a spatial resolution equivalent to Anger-SPECT. Results. Agreement rates between CZT- and Anger-SPECT were good irrespective of the study protocol (for abnormal SPECT, 201Tl: 94%, 99mTc-Low: 87%, 99mTc-High: 97%). Overall correlations were high for the extent of myocardial infarction (r=0.80) but lower for ischemic area (r=0.71), the latter being larger on Anger-SPECT (p<0.001). This larger extent was mainly observed in a sub-group of 50 obese patients who had a 201Tl or 99mTc-Low protocol and for whom stress myocardial counts were particularly low with Anger-SPECT (228±101 kcounts vs. 472±420 kcounts for other patients, p<0.001) but dramatically enhanced with CZT-SPECT (+279±251% vs. +168±116% for other patients, p<0.001). Conclusion. Although the overall concordance betweenCZT- and Anger-SPECT results is good, the use of CZT-cameras may lead to modified SPECT results, especially in cases of low Anger-SPECT counts and obese patients.