ASSESSMENT OF LIVER IRON OVERLOAD BY T2-QUANTITATIVE MAGNETIC-RESONANCE-IMAGING - CORRELATION OF T2-QMRI MEASUREMENTS WITH SERUM FERRITIN CONCENTRATION AND HISTOLOGIC GRADING OF SIDEROSIS

Purpose: To correlate hepatic 1/T2 values obtained by means of a T2-Qu antitative MRI (T2-QMRI) technique with three widely applied methods f or the evaluation of hemosiderosis, i.e., (a) liver iron concentration (LFeC) (b) serum ferritin (SF), and (c) histologic grading of sideros is. The impact of coexisting hepatitis was also considered. T2-QMRI me asurements were compared with signal intensity (SI) ratio measurements on conventional SE images. Materials and methods: Liver T2 relaxation times were calculated in 40 thalassemic patients, on an 0.5 T magneti c resonance imaging system using a multiple spin-echo sequence with pa rameters: TR = 2500 ms, TE = 12 ms in 20 symmetrically repeatable echo es. Results: (a) 1/T2 values were well correlated (r = 0.97) with live r iron concentration, which ranged from 2.32 to 18.0 mg/g dry weight ( normal <1.6 mg/g). (b) 1/T2 values were also correlated with serum fer ritin levels (r = 0.84). At various 1/T2 values, serum ferritin levels were higher for the anti-HCV(+) patients than the anti-HCV(-) ones. ( c) T2 values corresponding to successive grades of siderosis presented statistically significant differences. (d) SI ratio measurements assi gned less statistically significant results, as compared to T2 values. Conclusion: T2-QMRI measurement of T2 relaxation time is more accurat e than SI ratios in evaluating liver iron overload. It is particularly useful for hemosiderotic patients with coexisting hepatitis since, in this case, serum ferritin is not considered a reliable index of hemos iderosis.