Comparison of Tissue Elastography With Magnetic Resonance Imaging T2* and Serum Ferritin Quantification in Detecting Liver Iron Overload in Patients With Thalassemia Major.

Abstract

We investigated whether tissue elastography (TE) can be used as an alternative to magnetic resonance imaging (MRI) T2* analysis to determine the degree of iron overload in patients with thalassemia major. We conducted a prospective study of 154 patients (99 male; mean age, 12 ± 3.6 years) with thalassemia major requiring chronic blood transfusion and on iron chelator therapy. The study was performed at a tertiary hospital in India from January 2015 through June 2015. We performed routine blood sample analyses, measurements of serum levels of ferritin, and TE within 1 month of MRI T2* analysis of the liver. The Spearman correlation test and linearregression analysis were used to evaluate the correlation between TE liver stiffness measurements and R2* MRI results or serum ferritin levels. The subjects' mean total serum levels of bilirubin, alanine aminotransferase, aspartate aminotransferase, and albumin were 1.4 ± 0.6 mg/dL, 65.0 ± 51.8 IU/L, 62.9 ± 44 IU/L, and 4.2 ± 0.2 g/d, respectively. Mean liver stiffness measurement, MRI T2* (3 T), corresponding MRI R2* (3 T), and ferritin values were 8.2 ± 4.4 kPa, 3.18 ± 2.6 milliseconds, 617.3 ± 549 Hz, and 4712 ± 3301 ng/mL, respectively. On the basis of MRI analysis, 67 patients (43.5%) had mild iron overload, 49 patients (31.8%) had moderate iron overload, and 22 patients (14.3%) had severe iron overload. Fibroscan liver stiffness measurements correlated with MRI R2* values (r=0.85; P < .001). TE results identified the patients with severe, moderate, and mild iron overload with area under the receiver operating characteristic curve values of 94.8%, 84.5%, and 84.7%, respectively. Liver stiffness measurements greater than 13.5, 7.8, and 5.5 kPa identified patients with severe, moderate, and mild iron overload, respectively; the sensitivity and specificity values were 92% and 93% for severe overload, 82% and 82% for moderate overload, and 73% and 75% for mild overload. No correlation was found between TE results and serum level of ferritin (r= 0.19; P= .11). Results of TE correlate with those from MRI T2* analysis. TE is cheaper and more available than MRI and might be used to estimate hepatic iron overload, especially moderate to severe overload in patients with thalassemia major who require chronic transfusion.