FIG 2. Case 16, group A. In this patient, a 35 year–old woman with a nonfunctioning adenoma, MR studies were repeated at 3, 12, and 24 months after surgery and showed essentially the same findings, including HSI (arrow).

A and B, At 2 years after surgery, HSI is visible at the tip of pituitary stalk at the level of the diaphragma sellae on the coronal (A) and sagittal (B) sections.

C–F, Before surgery, linear HSI is visible at the posterior surface of adenoma, above the indentation formed by the diaphragma sellae, on the sagittal (C), coronal (D), contrast-enhanced sagittal (E), and axial (F) sections. HSI is identifiable at the stalk stump. The enhanced image shows HSI with more remarkable enhancing effect due to normal pituitary tissue; this finding suggests its connection to the pituitary stalk.