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Hepatic iron overload: quantitative MR imaging
J M Gomori1, G Horev, H Tamary
1Department of Radiology, Jerusalem, Israel.
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.
Insights
Magnetic resonance (MR) imaging can accurately measure liver iron concentration in patients with iron overload. This noninvasive technique correlates well with biopsy results, reducing the need for invasive procedures.
Area of Science:
- Radiology
- Medical Imaging
- Biophysics
Background:
- Iron deposits shorten T2 relaxation times.
- Previous studies showed poor correlation between in vivo hepatic 1/T2 and iron content.
- Accurate noninvasive assessment of liver iron is crucial for managing iron overload.
Purpose of the Study:
- To assess the utility of in vivo 1/T2 measurements using MR imaging for quantifying liver iron concentration.
- To compare MR imaging measurements with computed tomographic (CT) attenuation and liver biopsy in iron-overloaded patients.
Main Methods:
- In vivo hepatic 1/T2 measurements were obtained using MR imaging at 0.5 T with short echo times and single-echo-sequences.
- Liver iron concentration was determined from surgical wedge biopsy samples.
- CT attenuation was also measured as a comparative metric.
Main Results:
- A strong correlation (r = .93, P <= .0001) was found between in vivo hepatic 1/T2 measurements and liver iron concentrations (3–9 mg/g).
- CT attenuation did not correlate with liver iron concentration.
- MR imaging provided accurate, noninvasive assessment of hepatic iron.
Conclusions:
- Quantitative MR imaging is a reliable noninvasive method for assessing hepatic iron concentration in iron-overloaded patients.
- This technique can reduce the reliance on invasive liver biopsies.