[Reinjection of 201TL in postinfarct patients so as to improve the demarcation between cicatrix and ischemia]

In patients with earlier myocardial infarction the value of additional imaging after reinjection of 201Tl for better detection of ischemic myocardium was assessed. In 40 patients 40 MBq 201Tl were reinjected 24 h after stress and additional SPECT was performed 1 h later. Quantification of defect sizes showed a further reduction of 4 h redistribution defects by more than 30% in 18 patients. Comparison with clinical, electrocardiographic and scintigraphic parameters showed that none of these was sufficiently accurate for predicting additional thallium uptake after reinjection. In 22 patients with coronary angiography all 11 patients with collateralized occlusions of a coronary artery showed a reduction of the 4 h redistribution defect by > 20%, whereas all patients (5/5) with occlusions without distal collateralization had changes < 20%. This demonstrates that an improved thallium uptake after reinjection is typical of ischemic but vital myocardium.