Functional Neuroimaging in Craniopharyngioma: A Useful Tool to Better Understand Hypothalamic Obesity?

Abstract

Objective: To use functional magnetic resonance imaging (fMRI) in craniopharyngioma (CP) patients to examine the hypothesis that hypothalamic damage due to CP and its treatment results in enhanced perception of food reward and/or impaired central satiety processing. Methods: Pre- and post-meal responses to visual food cues in brain regions of interest (ROI; bilateral nucleus accumbens, bilateral insula, and medial orbitofrontal cortex) were assessed in 4 CP patients versus 4 age- and weight-matched controls. Stimuli consisted of images of high- (‘fattening’) and low-calorie (‘non-fattening’) foods in blocks, alternating with non-food object blocks. After the first fMRI scan, subjects drank a high-calorie test meal to suppress appetite, then completed a second fMRI scan. Within each ROI, we calculated mean z-scores for activation by fattening as compared to non-fattening food images. Results: Following the test meal, controls showed suppression of activation by food cues while CP patients showed trends towards higher activation. Conclusion: These data, albeit in a small group of patients, support our hypothesis that perception of food cues may be altered in hypothalamic obesity (HO), especially after eating, i.e. in the satiated state. The fMRI approach is encouraging for performing future mechanistic studies of the brain response to food cues and satiety in patients with hypothalamic or other forms of childhood obesity.

Hypothalamic Obesity in Patients with Craniopharyngioma: Profound Changes of Several Weight Regulatory Circuits

“…Before and after the scans, hunger ratings were performed. Following the test meal, controls showed suppression of activation in ROIs while CP patients showed trends toward higher activation in ROIs (Roth et al, 2011a). These preliminary data support our hypothesis that perception of food cues may be altered in HO, especially after eating.…”

Management of hypothalamic disease in patients with craniopharyngioma

“…Early reports of hyperphagia in CP patients led to a reluctance to consider bariatric surgery in this cohort; more recent studies have suggested that excessive calorie consumption in CP may be more subtle in aetiology—for example there may be a relative calorie excess in a state of low physical activity or there may be a selection of high‐calorie “reward” foods . Bariatric surgery therefore may be a viable tool to reduce the burden of HO in CP patients and can result in 10%‐20% weight loss at a year post‐surgery.…”

Hypothalamic Obesity in Craniopharyngioma Patients: Disturbed Energy Homeostasis Related to Extent of Hypothalamic Damage and Its Implication for Obesity Intervention

“…Functional magnetic resonance imaging (fMRI) is a powerful tool for observing the human brain’s in vivo responses to stimuli. One recent study tested satiety responses in a small group of four adolescent CP patients versus four BMI matched adolescent controls [ 79 ]. Following a test meal, controls showed suppression of activation by images of high-calorie, energy dense food while CP patients showed trends towards higher activation in regions of interest including the insula, nucleus accumbens, and medial orbitofrontal cortex.…”