Hepatic iron overload: quantitative MR imaging.

Abstract

Iron deposits demonstrate characteristically shortened T2 relaxation times. Several previously published studies reported poor correlation between the in vivo hepatic 1/T2 measurements made by means of midfield magnetic resonance (MR) units and the hepatic iron content of iron-overloaded patients. In this study, the authors assessed the use of in vivo 1/T2 measurements obtained by means of MR imaging at 0.5 T using short echo times (13.4 and 30 msec) and single-echo-sequences as well as computed tomographic (CT) attenuation as a measure of liver iron concentration in 10 severely iron-overloaded patients with beta-thalassemia major. The iron concentrations in surgical wedge biopsy samples of the liver, which varied between 3 and 9 mg/g of wet weight (normal, less than or equal to 0.5 mg/g), correlated well (r = .93, P less than or equal to .0001) with the preoperative in vivo hepatic 1/T2 measurements. The CT attenuation did not correlate with liver iron concentration. Quantitative MR imaging is a readily available noninvasive method for the assessment of hepatic iron concentration in iron-overloaded patients, reducing the need for needle biopsies of the liver.

Respiratory function in patients with thalassaemia and iron overload

“…Recently, KALTWASSER et al [10] reported a strong correlation between T2 relaxation time and hepatic iron concentration measured in biopsy specimens and a moderate correlation with serum ferritin. Likewise, GOMORI et al [11] found a significant correlation between hepatic T2 relaxation time and iron concentration measured in surgical wedge samples from the liver. A prior study [4] found that liver T2 values correlated with hepatic iron concentration and with serum ferritin.…”

Italian Society of Hematology practice guidelines for the management of iron overload in thalassemia major and related disorders

“…Nine studies of at least 10 thalassemic patients that evaluated the accuracy of measurement of LIC by MRI, and included a quantitative measurement of MRI signal and a detailed description of the patient population were selected (Table 2). 4,22,24,[26][27][28][29][30][31][32] Strong linear correlations (R 2 =approximate-ly 1.0) were demonstrated in four studies. 4,[27][28][29] The best result was obtained with the R2 methodology which resulted in a curvilinear relationship between R2 and LIC by biopsy over the entire clinically relevant range of LICs.…”

Hepatic iron overload in thalassemic patients: Proposal and validation of an MRI method of assessment

“…Although accurate, liver biopsy is an invasive procedure and cannot be used for routine follow-up. Other strategies have been proposed for noninvasive detection and quantitation of excess body iron, such as computed tomography [3,4] and magnetic susceptibility [5], but none have reproducible results [6]. Considerable data indicate that magnetic resonance imaging (MRI) is reliable in assessing tissue iron overload and distribution.…”