Pituitary Versus Hepatic Iron Assessment in Transfusion-Dependent Thalassemia: Is Signal Intensity Ratio a Reliable Tool?

Advances in transfusion and chelation have improved survival in transfusion-dependent thalassemia major (TDT), yet cumulative iron toxicity can impair endocrine function. We evaluated whether pituitary iron detected by MRI is associated with endocrine outcomes. Medical records of 60 pediatric TDT patients (mean age 11.5±4.4 years) were reviewed. Iron burden was estimated using serum ferritin and liver iron concentration (LIC) measured by R2 MRI. Pituitary iron was assessed on 1.5-T MRI with coronal and axial sequences using a signal intensity ratio (SIR) method, placing regions of interest in the pituitary gland and nasopharyngeal fat. Endocrine outcomes included short stature, thyroid dysfunction, and hypogonadism. Short stature was present in 25 patients (41.7%), subclinical hypothyroidism in 5 (8.3%), and hypogonadism in 9 (15%). Among 54 patients who underwent liver R2 MRI, 40 (74%) had no iron overload and 14 (26%) had mild accumulation. Neither serum ferritin nor LIC correlated with endocrine complications. Additionally, LIC did not correlate with the pituitary/fat SIR. Overall, the SIR method showed limited diagnostic utility and low specificity for assessing pituitary iron deposition. In this single-center pediatric cohort, pituitary SIR did not reflect hepatic iron load or predict endocrine morbidity. Given these limitations, quantitative T2/T2* techniques may offer greater accuracy for detecting pituitary iron overload. Larger, multicenter studies are warranted to validate the clinical relevance of pituitary MRI in the assessment of endocrine dysfunction in TDT.