Pituitary Gland Morphology: A Novel Diagnostic Marker for Differentiating Growth Hormone Deficiency from Idiopathic Short Stature in Children.

Background: The primary causes of short stature (SS) are idiopathic short stature (ISS) and growth hormone deficiency (GHD). The diagnosis of GHD relies on growth hormone stimulation tests (GHSTs), while the diagnosis of ISS is achieved through exclusion. Objectives: Growth hormone (GH) and insulin-like growth factor-I are the best therapeutic drugs for treating GHD, but their suitability for ISS remains controversial. Therefore, distinguishing between these two causes of SS is crucial. Currently, the diagnosis of GHD depends on GHSTs, whereas the diagnosis of ISS is achieved through exclusion, which is an invasive process. Thus, developing a noninvasive and convenient method to differentiate between GHD and ISS would be of great importance. Patients and Methods: We enrolled patients aged 3 -14 years who presented with SS and underwent GHSTs and pituitary gland (PG) magnetic resonance imaging (MRI) at our hospital from January 2020 to October 2022 for a cross-sectional study. A total of 205 patients were included, comprising 83 with ISS and 122 with GHD. The GHD patients were further divided into two groups based on the peak GH level in GHSTs. All patients underwent routine physical examinations, GHSTs, PG MRI, and X-rays of the left wrist. Two authors independently recorded the PG features (height, length, width, volume, pituitary stalk diameter, pituitary stalk length, and morphology). The PG morphology was categorized into three types: Convex, flat, and concave. Bone age was estimated from X-rays of the left wrist, which were reviewed by an experienced radiologist. Comparisons between the two groups were conducted using two independent samples t-tests or chi-square (χ²) tests. Results: There were no differences between the two groups regarding baseline clinical characteristics, except for the GH peak in GHSTs (P < 0.05). Pituitary stalk diameter, PG height, PG volume, and the dorsum sellae were significantly lower, while the tuberculum sellae was higher in the GHD group compared to the ISS group (all P < 0.05). The proportion of concave PG was higher, and the proportion of flat PG was lower in the GHD group (all P < 0.05). In subgroup analysis, PG height and PG volume were significantly lower in the absolute GHD (AGHD) group compared to the partial GHD (PGHD) group (all P < 0.05). Correlation analysis showed that PG height (r = 0.635, P < 0.01) and PG volume (r = 0.786, P < 0.01) were positively correlated with the GH peak level. Further analysis also demonstrated the differential diagnostic accuracy of PG height and PG volume, with high sensitivity (PG height: 66.3%; PG volume: 843%) and specificity (PG height: 85.2%; PG volume: 77.9%). Conclusion: pituitary gland height, PG volume, and the concave type of PG morphology may be very helpful in the differential diagnosis of GHD and ISS. [ABSTRACT FROM AUTHOR]