Ressonância magnética comparada à biópsia por agulha fina para estimativa da sobrecarga hepática de ferro em jovens portadores de anemia falciforme

Abstract

Objectives: To compare the results of the estimation of hepatic iron overload using magnetic resonance imaging (MRI) with that obtained by pathological examination of a fragment of liver tissue in young patients with sickle cell anemia (SCA). Methods: We studied 25 young subjects with SCA, which were assayed in serum ferritin by chemiluminescence (F), MRI and needle biopsy (BAF) of the liver. RM: There were five gradient-echo sequences and a spinecho. Signal intensity was obtained in each sequence by means of regions of interest in liver and paravertebral muscles to obtain the ratio of intensity of signal (RIS) liver/muscle. The RIS was obtained from the estimated hepatic iron concentration (CHEF) by the formula: e [5.808 - (0.877 × T2 *) - (1,518 × PI)], where T2 * is the RIS in sequence with echo time (TE) of 14 ms and PI is the RIS sequence with intermediate weighting. BAF: assessment of hepatic iron deposition was semiquantitative, performed according to the criteria established by Scheuer and employees, establishing categories increasing iron deposited (0-4). Continuous variables were compared using ANOVA. The correlations between the results obtained by each method were evaluated by Pearson correlation coefficient (r). Results: There was a statistically significant difference between the values of CHEF and intensity categories iron deposition (p = 0.004), as well as a strong positive correlation between these values and the CHEF (r = 0.75). Conclusion: MRI has proven to be a method correlated to the results obtained by liver biopsy by BAF in semi-quantitative determination of hepatic iron overload, may be an effective and safe for patients with AF.