Idiopathic growth hormone deficiency in the morphologically normal pituitary gland is associated with perfusion delay.

Abstract

To investigate quantitatively the topographic perfusion characteristics of the adenohypophysis by using dynamic contrast material-enhanced magnetic resonance (MR) imaging in a subgroup of patients with idiopathic growth hormone deficiency (IGHD) and with normal-appearing pituitary morphology on MR images. This HIPAA-compliant, prospective study was approved by an institutional review board, and informed consent was obtained for all patients. Twenty-five patients (mean age, 10.6 years ± 3.3 [standard deviation]) with clinical growth retardation, proved IGHD, and normal pituitary morphology on MR images were included for analysis. Sixteen children (mean age, 10.8 years ± 5.5) were included as control subjects. Time to peak (TTP) perfusion properties of the adenohypophysis in 10 regions of interest from multisection coronal dynamic contrast-enhanced T1-weighted MR images were quantitatively derived by using the Brix pharmacokinetic model. Significant difference was determined with a two-tailed Student t test. The Pearson correlation coefficient was used to correlate the perfusion parameters, including maximal enhancement peak and slope, with serum growth hormone levels in the IGHD group. TTP for the IGHD group was significantly prolonged compared with that for the control group (P < .005). The prolonged TTP in the IGHD group was found to be diffuse. The levels of growth hormone deficiency were negatively correlated with the peak enhancement and the slope of the wash-in phase, which suggests increased blood volume in IGHD within the pituitary gland. IGHD and the degree of growth hormone deficiency are associated with nonregional perfusion delay in morphologically normal adenohypophyses. The lack of lateralization of perfusion delay may suggest that microvascular structural abnormalities play a role in IGHD.