The aim of this study was to carry out a quantitative analysis in order to compare 99mTc-sestamibi (99mTc-MIBI) uptake at rest with that of Thallium-201 (201Tl) among patients with ejection fraction lower than 35%. Methods: twenty-eight patients (average age 63 ± 14 years) with ischemic cardiopathy, were submitted to scintigraphy with 201Tl and 99mTc-MIBI. A quantitative analysis was carried out using a model of 17 myocardial segments. The myocardial 99mTc-MIBI uptake at rest was compared to images of late 201Tl redistribution in a total of 476 segments. The regional contractile function was assessed visually using the 99mTc-MIBI images gated to the electrocardiogram. Three myocardials segments groups were formed: group 1, normal kinetic; group 2, hypokinetic; and group 3, akinetic or dyskinetic. Results: A 90.3% concordance per segment was obtained between both tracers, considering a uptake cutoff point of amp;#8805; 50% in the viability assessment, with a Kappa coefficient of 0.671. Linear regression analysis showed a statistically significant correlation between the uptake of both tracers (r = 0.81; plt;0.0001). The Bland-Altman method, applied per patient, demonstrated that 96.4% of the differences between the activities of the two tracers ranged between 6.2 and +10.5%. Regarding the segment contractile function, there was no significant difference between the average uptake of the radioisotopes in groups 1 and 2, but there was a significant difference in group 3, where 99mTc-MIBI uptake was inferior to 201Tl uptake, 55 ± 25% x 60 ± 22%, respectively (p=0.001). Conclusion: Quantitative analysis of myocardial 99mTc-MIBI uptake at rest allows to detect viable myocardium. However, in segments with severe contractile dysfunction, the uptake of 99mTc-MIBI is inferior to that of 201Tl
The aim of this study was to carry out a quantitative analysis in order to compare 99mTc-sestamibi (99mTc-MIBI) uptake at rest with that of Thallium-201 (201Tl) among patients with ejection fraction lower than 35%. Methods: twenty-eight patients (average age 63 ± 14 years) with ischemic cardiopathy, were submitted to scintigraphy with 201Tl and 99mTc-MIBI. A quantitative analysis was carried out using a model of 17 myocardial segments. The myocardial 99mTc-MIBI uptake at rest was compared to images of late 201Tl redistribution in a total of 476 segments. The regional contractile function was assessed visually using the 99mTc-MIBI images gated to the electrocardiogram. Three myocardials segments groups were formed: group 1, normal kinetic; group 2, hypokinetic; and group 3, akinetic or dyskinetic. Results: A 90.3% concordance per segment was obtained between both tracers, considering a uptake cutoff point of amp;#8805; 50% in the viability assessment, with a Kappa coefficient of 0.671. Linear regression analysis showed a statistically significant correlation between the uptake of both tracers (r = 0.81; plt;0.0001). The Bland-Altman method, applied per patient, demonstrated that 96.4% of the differences between the activities of the two tracers ranged between 6.2 and +10.5%. Regarding the segment contractile function, there was no significant difference between the average uptake of the radioisotopes in groups 1 and 2, but there was a significant difference in group 3, where 99mTc-MIBI uptake was inferior to 201Tl uptake, 55 ± 25% x 60 ± 22%, respectively (p=0.001). Conclusion: Quantitative analysis of myocardial 99mTc-MIBI uptake at rest allows to detect viable myocardium. However, in segments with severe contractile dysfunction, the uptake of 99mTc-MIBI is inferior to that of 201Tl
