The influence of pituitary volume on the growth response in growth hormone-treated children with growth hormone deficiency and idiopathic short stature.

Purpose: Magnetic resonance imaging (MRI) can be used for assessing the morphology of pituitary gland. The purpose of this study was 1) to determine whether the pituitary volume (PV) distinguish growth hormone (GH) deficiency from idiopathic short stature (ISS) and 2) to validate an association between PV and severity of GH deficiency and 3) to compare the PV between good and poor response groups in children with GH deficiency and ISS. Methods: Data were collected from the medical records of 152 children with short stature who underwent GH stimulation test, sella MRI, and GH treatment. Estimated PV were calculated using the formula of an ellipsoid. We compared the PV in patients with GH deficiency with that of patients with ISS. In addition, we assessed the association between PV and severity of GH deficiency, and growth response after treatment. Results: No difference was observed in the PV between patients with GH deficiency and ISS. The PV seemed to be smaller as the degree of GH deficiency was severe (P=0.082). The PV in good response group was smaller than that in poor response group in patients with GH deficiency (P< 0.005). The PV showed no association with responsiveness to GH treatment in patients with ISS (P=0.073). Conclusions: The measurement of PV cannot be used for differential diagnosis between GH deficiency and ISS. In patients with GH deficiency, the PV tend to be smaller as the severity of GH deficiency even though no statistical significance, and may be a good response predictor for GH treatment.