Assessment of resting thallium-201 reinjection after stress-delayed Tl imaging (I): Comparison with 24-hour scan and regional wall motion

Clinical value of resting reinjection of 1 mCi (37 MBq) of Tl after stress-delayed scan was assessed in comparison with 24 hr delayed scan and regional wall motion (RWM) in 37 patients with coronary artery disease. Of 101 segments with initial perfusion abnormality, concordant findings were observed after Tl reinjection in 67 segments (66%). But redistribution (RD) after Tl reinjection was observed in 19 of the 52 persistent defect (PD) segments (37%), and complete RD was observed 15 of the 43 segments (35%) where 3 hr scan showed incomplete RD. On the other hand, concordant findings were observed on 24 hr delayed scan in 11 of the 20 segments with perfusion abnormality (55%). RD on 24 hr delayed scan was observed in 5 of the 13 PD (38%), but it was not apparent in 3 of the 7 segments where 3 hr scan showed RD. Furthermore the segments which showed RD after Tl reinjection in PD segments tend to have less severe RWM abnormality than the sustained PD segments (RWM score: 1.65 +/- 1.17 vs. 2.29 +/- 1.05, p less than 0.05). These data indicate that Tl reinjection which permits assessment of RD with good quality images on the same day is considered as a valuable means for assessing myocardial viability.