T2 relaxation rate as an index of pituitary iron overload in patients with beta-thalassemia major.

OBJECTIVE

In transfusion-dependent ss-thalassemia major, increased iron deposition in the pituitary gland has a cytotoxic effect, leading mainly to hypogonadotropic hypogonadism. Early detection and quantification of iron in the pituitary gland are of particular importance for successful treatment. The purpose of this study was to evaluate the T2 relaxation rate (1/T2) as a marker of pituitary siderosis.

SUBJECTS AND METHODS

In 29 patients with ss-thalassemia major and 40 controls, we assessed the 1/T2 of the pituitary gland in a 1.5-T MR unit, using a multiecho spin-echo sequence. In all patients, an extensive endocrine evaluation was performed, including measurements of spontaneous and stimulated levels of gonadotropins, thyroid hormones, growth hormone, insulinlike growth factor, and adrenal hormones.

RESULTS

A positive correlation was found between the 1/T2 and the serum ferritin level (r = 0.73, p < 0.001). The 1/T2 was higher in patients (mean, 0.020 msec(-1); SD, 0.006) compared with that of controls (mean, 0.011 msec(-1); SD, 0.001; p < 0.001). The 1/T2 was higher in patients with hypogonadotropic hypogonadism (mean, 0.024 msec(-1); SD, 0.006) in comparison with that of patients without any pituitary dysfunction (mean, 0.017 msec(-1); SD, 0.004; p < 0.05).

CONCLUSION

The T2 relaxation rate could be used as an index of pituitary iron overload, and it might be of value to monitor treatment with deferoxamine in patients with ss-thalassemia major.