RESUMEN
OBJECTIVES: To assess the level of agreement and interchangeability among different software programs for calculation of T2 values for iron overload. METHODS: T2 images were analysed in 60 patients with thalassaemia major using the truncation method in three software programs. Levels of agreement were assessed using Pearson correlation and Bland-Altman plots. Categorical classification for levels of iron concentration by each software program was also compared. RESULTS: For the heart, all correlation coefficients were significant among the software programs (P < 0.001 for all coefficients). The mean differences and 95% limits of agreement were 0.2 (-4.73 to 5.0); 0.1 (-4.0 to 3.9); and -0.1 (-4.3 to 4.8). For the liver all correlations were also significant with P < 0.001. Bland-Altman plots showed differences of -0.02 (-0.7 to 0.6); 0.01 (-0.4 to 0.4); and -0.02 (-0.6 to 0.6). There were no significant differences in clinical classification among the software programs. CONCLUSIONS: All tools used in this study provided very good agreement among heart and liver T2 values. The results indicate that interpretation of T2 data is interchangeable with any of the software programs tested. KEY POINTS: Magnetic resonance imaging in iron overload assessment has become an essential tool. Post processing options to establish T2 values have not been compared. No differences were found on T2 of the liver or heart using 3 different techniques. Availability of these methods should allow more widespread interpretation of iron overload by MRI.
Asunto(s)
Sobrecarga de Hierro/diagnóstico , Hígado/patología , Imagen por Resonancia Magnética , Miocardio/patología , Programas Informáticos , Talasemia beta/diagnóstico , Adulto , Estudios Transversales , Femenino , Humanos , Hierro/metabolismo , Sobrecarga de Hierro/patología , Hígado/metabolismo , Masculino , Miocardio/metabolismo , Talasemia beta/patologíaRESUMEN
BACKGROUND: Iron chelation therapy in patients with thalassemia major may not prevent iron overload in all organs, especially those in which iron enters cells through specific calcium channels. We designed a controlled pilot study to assess the potential of the calcium channel blocker amlodipine in strengthening the efficacy of iron chelation. METHODS: Fifteen patients with thalassemia major undergoing chelation therapy were randomized to receive amlodipine added to standard treatment in a 1:2 allocation for 12 months. T2* values for assessment of iron overload in the liver and heart using magnetic resonance imaging were obtained at baseline and at 6 and 12 months. RESULTS: In the amlodipine-treated group, heart T2* increased significantly in comparison to baseline at 6 and 12 months (21.7 ± 7.2 ms to 28.2 ± 7.9 ms and 28.3 ± 8.0 ms, with P = .007 and .03, respectively), while no differences were observed in the control group (25.1 ± 8.8 ms to 24.7 ± 7.8 ms and 26.2 ± 11.4 ms; P = .99 and 0.95, respectively); significant differences between groups were observed at 6 months (28.2 ± 7.9 ms vs 24.7 ± 7.8 ms in the control group, P = .03). A significant reduction in ferritin levels also was observed in the treated group at 12 months. CONCLUSIONS: The use of amlodipine in conjunction with standard chelation therapy may suggest a new strategy in preventing and treating iron overload in patients with thalassemia major, especially in organs where iron absorption depends on active uptake by calcium channels like the heart.