Objective: In patients with growth hormone deficiency (GHD), even in those with no major organic lesion, anterior pituitary height (APH) is reported decreased. Limitations in the evaluation of APH and changes according to pubertal status make its validity questionable. Recently, in a small scale study, pons ratio (PR) has been suggested as a more sensitive marker for evaluation of pituitary gland in GHD patients. The study aims to evaluate the validity of PR as a diagnostic tool in GHD.
Method: We retrospectively evaluated the pituitary MRI of patients with a diagnosis of GHD. Primary axis(PA) was assigned as a line crossing the midsaggital dorsum sella and fourth ventricle which divides pons into two symmetrical parts. PR was defined as the pons height above the PA divided by total pons height. The PR of patients with GHD was compared with patients with no GHD.
Results: Study included 138 patients with GHD (84 male) and 28 healthy controls. While 127 patients (92%) had isolated GHD, 11 (8%) had multiple pituitary hormone deficiencies (MPHD). In the isolated GHD group, 18 patients (14.2%) had an organic lesion on pituitary MRI. The PR measured for GHD patients (mean: 0.32±0.90; range: 0.15-0.63) was higher compared to those of the control subjects (mean: 0.27±0.63; range: 0.19-0.44) (p:0.005). There was a statistically significant moderate negative correlation between PR and pituitary height (r:-0.273; p:0.002). The PR of GHD patients who had an organic brain lesion (mean: 0.37±10; range: 0.15-0.55) was higher than those with no organic lesion (mean: 0.32±0.86; range: 0.17-0.63) (p:0.016). ROC analysis revealed the best cut-off value of PR as 0.27 for GHD with a sensitivity of 71% and specificity of 53%. In addition, bone age, peak GH value in the GH stimulation test and IGF1-SDS was negatively correlated with PR with r:-0.375 (p:0.000), r:-0.246 (p:0.005) and r:-0.281 (p:0.003) respectively. Although the pituitary height was higher in pubertal subjects compared to the prepubertal group, there was not a statistically significant difference between the PR of prepubertal and pubertal patients.
Conclusion: As is not change depending on pubertal status, PR can potentially be a more sensitive tool for evaluation pituitary gland in GHD patients compared to APH. PR measurement is a noninvasive, practical and cost-benefit method that can be measured using a sagittal section of routine pituitary MRI.
19 - 21 Sep 2019
European Society for Paediatric Endocrinology