Defect reversibility using thallium-201 reinjection. Comparison of stress-redistribution-reinjection with stress-immediate reinjection.

Immediate poststress thallium-201 reinjection followed by imaging one hour later has been proposed as an alternative reinjection protocol. This procedure is patient-convenient and time-saving as it shortens the investigation time to maximally 2.5 hours. The efficacy of the immediate thallium-201 reinjection protocol was assessed in 305 patients with stress perfusion defects in whom we compared the scintigraphic findings of 210 consecutive patients who underwent the standard thallium-201 stress/redistribution/reinjection protocol (Group I), with 95 consecutive patients who subsequently underwent the thallium-201 stress/immediate reinjection protocol (Group II). In all patients three-view planar images were visually and quantitatively analyzed. In Group I, defect reversibility was observed in 433 of 622 (70%) stress perfusion defects compared to 220 of 320 (69%) segments in Group II (p = NS). With respect to Q-wave related segments, defect reversibility was seen in 102 of 172 (59%) segments in Group I compared to 34 of 63 (54%) in Group II (p = NS). Based on defect reversibility, the diagnosis of myocardial ischemia was made in 184 of 210 (88%) patients Group I compared to 86 of 95 (91%) patients in Group II (p = NS). These findings indicate that immediate thallium-201 reinjection imaging provides at least similar data on defect reversibility as the standard thallium-201 stress/redistribution/reinjection approach. In practical terms, the stress/immediate reinjection approach seems advantageous as it reduces imaging time, enhances patient throughout and can be considered as one comprehensive imaging procedure.