HYPOTHALAMIC-PITUITARY VASCULARIZATION IN PITUITARY-STALK TRANSECTIONSYNDROME - IS THE PITUITARY-STALK REALLY TRANSECTED - THE ROLE OF GADOLINIUM-DTPA WITH SPIN-ECHO T1 IMAGING AND TURBO-FLASH TECHNIQUE

We examined 14 patients, aged 10-25 years, with idiopathic hypopituita rism. All presented an ectopic posterior pituitary at the median emine nce with a hypoplastic anterior pituitary on magnetic resonance imagin g (MRI). Eight patients had isolated growth hormone deficit (IGHD) and six had multiple hormone deficits (MPHD). Unenhanced MRI showed the p ituitary stalk, which was extremely thin, in only three patients, whil e T1-weighted images obtained after intravenous injection of gadopente tate dimeglumine (Gd-DTPA) showed a thin pituitary stalk in seven pati ents (six with IGHD and one with MPHD), demonstrating a preserved vasc ular component of the stalk. MRI with Gd-DTPA was more sensitive than unenhanced MRI in detecting the pituitary stalk in patients with hypop ituitarism with an ectopic posterior pituitary: the stalk was demonstr ated in 50% of the cases (seven patients), versus 21.4% (three patient s) by unenhanced MRI. The dynamic study of the hypothalamo-hypophyseal axis performed with turbo-FLASH sequences after bolus injection of Gd -DTPA showed the residual anterior pituitary to have arterial enhancem ent times, which suggests that an arterial system compensates for the absent or diminished blood supply from the portal system, independent of stalk detection.