MRI in haemochromatosis: pituitary versus testicular iron deposition in five patients with hypogonadism

Evaluation of semen quality, endocrine profile and hypothalamus-pituitary-testis axis in male patients with homozygous beta-thalassemia major

PURPOSE

The endocrine profile, hypothalamus-pituitary-testis axis and semen quality were evaluated in male patients with homozygous beta-thalassemia major.

MATERIALS AND METHODS

A total of 168 male patients 18 years or older with homozygous beta-thalassemia major were enrolled in the study and 84 healthy age matched male volunteers served as controls. All subjects provided a medical history and underwent physical examination and routine semen analysis. Two blood samples were drawn from each participant at 20-minute intervals to determine the resting levels of certain hormones, including luteinizing hormone, follicle-stimulating hormone, prolactin, testosterone, estradiol, insulin-like growth factor-1 and insulin like growth factor binding protein-3. The hypothalamus-pituitary-testis axis was also assessed using the luteinizing hormone-releasing hormone test.

RESULTS

The prevalence of hypogonadotropic hypogonadism was 76.2% (128 patients). Of the studied patients with homozygous beta-thalassemia major 75 (44.6%) were short. Compared with normal controls the patients with homozygous beta-thalassemia major had lower serum luteinizing hormone, follicle-stimulating hormone, insulin-like growth factor-1, insulin-like growth factor-1 binding protein-3 and testosterone. In addition, there were decreased luteinizing hormone and follicle-stimulating hormone responses to luteinizing hormone-releasing hormone in patients with homozygous beta-thalassemia major compared to those in normal controls. Total sperm count, sperm motility and percent normal sperm morphology were lower in patients with homozygous beta-thalassemia major than in controls.

CONCLUSIONS

Most subjects with beta-thalassemia major have hypogonadotropic hypogonadism state, impairment fertility and growth retardation. Further studies are warranted to better clarify the causes and consequences of hypogonadotropic hypogonadism in patients with homozygous beta-thalassemia major.

Transfusional hemochromatosis: quantitative relation of MR imaging pituitary signal intensity reduction to hypogonadotropic hypogonadism

PURPOSE

To assess the relationship between magnetic resonance (MR) imaging pituitary signal intensity reduction in patients with transfusional hemochromatosis and the clinical manifestation of hypogonadotropic hypogonadism.

MATERIALS AND METHODS

Pituitary MR imaging at 0.5 T was performed in 38 consecutive patients affected by secondary hemochromatosis and in 20 healthy volunteers. Serum ferritin levels were estimated in the affected population. Twenty (53%) of the 38 patients had hypogonadotropic hypogonadism diagnosed. Pituitary-to-fat signal intensity ratios were calculated from coronal gradient-echo (GRE) T2*-weighted MR images. The relationship between the quantitative reduction of the pituitary-to-fat signal intensity ratio and the clinical manifestation of pituitary dysfunction was assessed in the affected population. Signal intensity reduction in the anterior lobe of the pituitary gland was also correlated with the serum ferritin level.

RESULTS

The degree of reduction of the pituitary-to-fat signal intensity ratio correlated with the presence of hypogonadotropic hypogonadism, with a sensitivity of 90%, a specificity of 89%, and an overall accuracy of 89%. In addition, the reduction of pituitary signal intensity was greater in patients with higher ferritin levels (r = -0.55, r(2) = -0.30, P <.001).

CONCLUSION

The degree of signal intensity reduction, measured as the pituitary-to-fat signal intensity ratio for GRE T2*-weighted images, in patients with secondary hemochromatosis correlates with the severity of pituitary dysfunction.

Magnetic resonance imaging of the pituitary gland in patients with secondary hypogonadism due to transfusional hemochromatosis

To identify pituitary iron overload in patients with transfusional hemochromatosis causing secondary hypogonadism, we prospectively evaluated signal intensity abnormalities of the anterior lobe of the pituitary gland of 18 patients affected by transfusion-dependent thalassemia major and secondary hypogonadism. Magnetic resonance (MR) imaging is useful to assess pituitary iron overload in patients with transfusional hemochromatosis and secondary hypogonadism by detection of a significant decreased signal intensity of the anterior lobe of the pituitary gland on GRE T2*-weighted images. The decreased signal intensity of the anterior lobe of the pituitary gland on GRE T2*-weighted images was correlated to increasing serum ferritin level (r = -0.84, r2 = -0.70, P < 0.001). Indeed, the lower the signal intensity of the pituitary gland, the greater the serum ferritin level. However an exact quantification of pituitary iron overload by correlation with serum ferritin level is not allowed. No correlation was found between MR imaging results and hormonal status; however, the detection of pituitary iron overload on GRE T2*-weighted images is consistent with the hypothesis of hypogonadotrophic pituitary insufficiency due to iron-induced cellular damage.