T2-star (T2*) magnetic resonance imaging for assessment of kidney iron overload in thalassemic patients

Abstract

Background: Improved survival in thalassemic patients has lead to the manifestation of morbidities such as renal dysfunction. This involvement suggests the need for a reliable and non-invasive method to assess the degree of kidney iron overload. We conducted the present study to evaluate the relationship between serum ferritin levels, liver, heart, and kidney MRI gradient echo (T2*) relaxation times in thalassemic patients, as a step to evaluate the feasibility of using MRI T2* to assess the degree of kidney iron overload.

Methods: This was a prospective study of 120 (60 males, 60 females) regularly transfused thalassemic patients (mean age: 25.9 ± 9 years) who suffered from major and intermediate thalassemia. Patients attended an adult thalassemia clinic located in Tehran, Iran. Cardiac, hepatic and renal MRI T2* were performed. Serum ferritin levels were measured.

Results: Our results indicated a moderate correlation between kidney MRI T2* relaxation time and serum ferritin (r = -0.446, P < 0.001). Kidney MRI T2* relaxation time weakly correlated with liver MRI T2* relaxation time (r = 0.388, P < 0.001) and cardiac MRI T2* relaxation time (r = 0.338, P = 0.023).

Discussion: The moderate correlation between kidney MRI T2* relaxation time and serum ferritin, and its weak correlation with liver and heart T2* relaxation times indicate that relying on liver and heart MRI T2*, as well as serum ferritin levels to predict the exact condition of kidney iron overload might not be a reliable approach. Our findings suggest the use of kidney MRI T2* as a noninvasive method for evaluating renal iron overload in thalassemic patients. Further studies to investigate the relation between kidney MRI T2* relaxation times and renal function, as well as the cost benefit of using this method, are suggested.