Significance of fill-in after thallium-201 reinjection following delayed imaging: comparison with regional wall motion and angiographic findings 
 To identify reversible defects, reinjection of a small amount of thallium-201 (201Tl) following 3-hr delayed imaging was performed in 60 patients with coronary artery disease who had perfusion abnormalities on their post-exercise 201Tl images.
 Thallium-201 uptake was visually scored and judged as normal (Group 1), reversible defect (Group II), new fill-in after reinjection (Group IIIa) and no fill-in even after reinjection (Group IIIb).
 New fill-in after reinjection was observed in 27 segments of the 85 segments (32%), showing persistent defect on the stress and delayed images.
 The wall motion in Group IIIa was worse than Group II but better than Group IIIb.
 Group IIIa showed Q-wave on ECG more often (69%) than Group II (27%) (p less than 0.01), but less often than Group IIIb (85%) (p less than 0.05).
 These data indicate that the reinjection 201Tl imaging often identifies new fill-in in the areas of no redistribution on the delayed images and it may hold promise for assessing tissue viability which the conventional imaging may underestimate.
