Dual-isotope SPET 201Tl rest/99mTc-MIBI stress: one-day protocol for pre-operative myocardial imaging?

We compared the results of a rest 201TI/stress 99mTc-MIBI protocol, both by means of separate single isotope and simultaneous dual isotope acquisition, with a standard stress/rest 99mTc-MIBI 2-day protocol in 11 patients with low probability of CAD and 14 patients with chronic CAD. In patients with CAD 406 segments (sgs) were analysed. In the standard protocol 119 sgs were classified as pathological of which 50.4% were fixed and 49.6% reversible defects. With the MIBI-stress/TI-rest single 33% of 119 pathological sgs were fixed and 67% reversible defects. With the MIBI-stress/TI-rest dual only 20% were fixed and 80% reversible defects. The reversibility of 59 MIBI-stress/MIBI-rest reversible defects was quantified: MIBI-stress/MIBI-rest 35 +/- 16% MIBI-stress/TI-rest single 50 +/- 26% and MIBI-stress/TI-rest dual 48 +/- 22%. The results of 99mTc-MIBI rest and 201TI rest studies in patients with chronic CAD are not the same. Dual-isotope 1-day 201TI-rest/99mTc-MIBI-stress SPET data, acquired separately, may give fast and complete information on myocardial perfusion at stress and rest, respectively, and on myocardial viability.