Semiquantitative analysis of hypothalamic damage on MRI predicts risk for hypothalamic obesity

ObjectiveExcessive weight gain frequently occurs in patients with hypothalamic tumors and lesions leading to hypothalamic obesity (HO). MethodsDigital brain magnetic resonance imaging (MRI) and clinical outcomes were studied retrospectively in a single center, including 45 children with postoperative lesions in the sellar region (41 craniopharyngiomas, 4 with Rathke's cleft cysts), approximate to 5 years post-surgery, mean age 13.9 years. Four standard sections covering hypothalamic areas critical to energy homeostasis were used to assess lesions and calculate a hypothalamic lesion score (HLS); the association with HO was examined. ResultsCompared to subjects who did not develop HO (n = 23), subjects with HO (n = 22) showed more frequently lesions affecting the third ventricular floor, mammillary bodies, and anterior, medial (all P<0.05), and most importantly posterior hypothalamus (P < 0.01). The HLS correlated significantly with BMI z-score changes 12 and 30 months post-surgery, even after adjusting for potential confounders of gender, age at surgery, surgery date, surgery BMI z-score, hydrocephalus, and residual hypothalamic tumor (r = 0.34, P = 0.03; r = 0.40, P = 0.02, respectively). Diabetes insipidus was found to be an endocrine marker for HO risk. ConclusionsThe extent of damage following surgery in the sellar region can be assessed by MRI using a novel scoring system for early HO risk assessment.