Objective To study the importance of hypothalamus-pituitary region magnetic resonance imaging (MRI) and serum insulin-like growth factor-1 (IGF-1) in the clinical diagnosis of girls with idiopathic central precocious puberty(ICPP). Methods 60 ICPP female patients diagnosed between February 2007 and December 2009 were selected from Department of Pediatric Endocrinology, Provincial Hospital Affiliated to Shandong University. Fasting serum was collected from the early ICPP group with 8 patients, the typical ICPP group with 36 patients and the ICPP associated with growth hormone deficiency(GHD) group with 16 patients. IGF-1 and growth hormone (GH) were detected by radio immune assay (RIA), and (0min) FSH, LH, E2, the peak of LH and LH/FSH after the stimulation of GnRHa were detected by immunochemiluminometric assays(ICMA). In the ICPP associated with GHD group, Growth Hormone Stimulation Test was plused. The MRI of the hypothalamus and the pituitary gland (the anterior pituitary height was measured and classified to 5 grades by Elster)， the ultrasound of ovaries and uterus， the bone age(BA)were observed. 30 healthy prepuberty girls were selected as the contrast group. All the indicators above were compared among the three groups. The relevance between the anterior pituitary height and the fasting serum IGF-1, E2, basal LH and LH/FSH, peak LH and LH/FSH, the difference between BA and chronological age(BACA) was analyzed. Results Serum E2, peak LH and LH/FSH, CA, (BA-CA) in the early ICPP group were significantly lower than those in the typical ICPP group (P<0.01). Compared with those of the control group, the anterior pituitary height and the IGF-1 in the typical ICPP group and the early ICPP group were both significantly higher (P<0.01). The anterior pituitary height and the IGF-1 in the two groups showed no significant difference (P>0.05). GnRHa treatment had significant effect on the early ICPP group. The anterior pituitary height showed a significant linear positive correlation with fasting serum IGF-1, E2, basal LH and LH/FSH, peak LH and LH/FSH, (BA-CA) (r=0.65，0.54，0.54，0.45，0.58，0.57，0.45，P<0.05). In the typical ICPP group, (BA-CA), the anterior pituitary height and the IGF-1 were significantly higher than those in the ICPP associated with GHD group (P <0.01), the peak LH and LH/FSH were higher than those in the ICPP associated with GHD group (P<0.05). Compared with those in the control group, the anterior pituitary height and the serum IGF-1 in the ICPP associated with GHD group were significantly lower (P <0.01). Conclusion The value of MRI and IGF-1 is significant in the early diagnosis of ICPP girls and the differential diagnosis between ICPP and ICPP associated with GHD girls. MRI is closely related to the functions of the hypothalamus-pituitary-gonad axis.
