The Assessment of Brain Volume Differences in Idiopathic Central Precocious Puberty Girls; Comparison of Age-Matched Girls and Normal Puberty Girls

Abstract

Objective: Although there have been several studies on the neuroanatomical changes in idiopathic central precocious puberty (ICPP), the association between each brain region and ICPP has not yet been clearly elucidated. This study aimed to evaluate the difference in brain structure in ICPP compared with age-matched healthy controls and normal puberty controls, and additionally the correlation between brain volume difference and the luteinizing hormone (LH).

Materials and methods: The study enrolled fifteen girls with ICPP, as well as 15 age-matched healthy girls and 15 normal puberty girls as controls. The subjects underwent a 1.5 Tesla Avanto MR Scanner. Anatomical T1-weighted images were acquired with a T1 spin-echo sequence. The volumes of total and regional brain were compared with each of the two control groups and analyzed through the paired T-test, and the brain region related to the peak LH level was also analyzed through a simple correlation test.

Results: The mean age of the ICPP group, age-matched group, and puberty group were 8.0 ± 0.9 years, 7.8 ± 0.9 years, and 11.9 ± 0.9 years, respectively. In our findings, the regional cerebral volumes in ICPP were different from age-matched controls. Compared with controls, ICPP showed a significant increase in gray matter (GM) volumes (the medial prefrontal cortex, superior parietal gyrus, supramarginal gyrus, angular gyrus, postcentral gyrus, superior occipital gyrus, cuneus, hippocampus, parahippocampal gyrus, posterior cingulate gyrus (PCgG), cerebellar cortex (Cb)) and in white matter (WM) volumes (the insular, caudate, splenium of corpus callosum (p < 0.001)). Especially, the GM volumes of the PCgG (r = 0.57, p = 0.03) and Cb (r = 0.53, p = 0.04) were correlated positively with LH concentrations stimulated by the gonadotropin-releasing hormone agonist. Compared to the normal puberty control, no significant difference in GM volume was found.

Conclusions: This study showed the overall brain volumetric differences between ICPP girls and age-matched controls using voxel-based morphometric analysis, and further showed the correlation between brain volume and the sex hormone in ICPP. Through a comparison between the two groups, the cerebral development pattern of ICPP is similar to that of normal puberty, and these local differences in cerebral volume may affect social and congenital changes. These findings will be useful for understanding the neuroanatomical mechanisms on the specific morphological variations associated with ICPP.

Keywords: gray matter; luteinizing hormone; magnetic resonance imaging; precocious puberty; white matter.

Figure 1

Brain areas with a significant increase in GM (a) and WM (b) volumes in ICPP girls in contrast to age-matched healthy girls (uncorrected; p < 0.001, excluded 100 voxels). Hi, hippocampus; PHG, parahippocampal gyrus; PCgG, posterior cingulate gyrus; Cun, cuneus; PoG, postcentral gyrus; SCC, splenium of corpus callosum; mPFC, medial prefrontal cortex; Ang, angular gyrus; SMG, supramarginal gyrus; SPG, superior parietal gyrus; STG, superior temporal gyrus; Ins, insula; Cd, caudate nucleus; Cb, cerebellar cortex.

Figure 2

Brain areas with a significant difference in WM volumes in ICPP girls in contrast to normal puberty girls (uncorrected; p < 0.001, excluded 100 voxels). SCC, splenium of corpus callosum; PCgG, posterior cingulate gyrus.

Figure 3

Scatterplot of correlation between LH level and increased GM; PCgG (MNI x, y, and z coordinates 3, −48, and 21) (a) and Cb (−23, −69, −47) (b) in ICPP girls. Each correlation coefficient is 0.57 (p* = 0.03) and 0.53 (p* = 0.04) in PCgG and Cb. * p value is uncorrected on this model.