Gadolinium-DTPA and MR imaging of pituitary adenoma: a preliminary report

Gadolinium-DTPA MR imaging (Gd-MR), unenhanced MR imaging, and contrast-enhanced CT studies were compared prospectively in six patients with surgically confirmed pituitary adenomas and three patients without sellar pathology to determine the utility of Gd-MR in the diagnosis of pituitary adenoma. In normal patients, the pituitary gland, cavernous sinus, and infundibulum enhanced by T1 shortening after gadolinium. In adenoma patients, two of four focal lesions identified with contrast-enhanced CT were identified with Gd-MR, and one was identified with unenhanced MR. The earliest short repetition-time sequence performed after gadolinium injection was best for focal lesion detection. Normal cavernous sinus enhancement by gadolinium made identification of cavernous sinus extension of adenoma difficult. Infundibulum displacement was better seen with contrast-enhanced CT (two vs one); however, unenhanced and Gd-MR were better than contrast-enhanced CT for demonstrating chiasmal compression (four vs three). Contrast-enhanced CT, Gd-MR, and plain MR were equally able to identify gland enlargement, sellar floor erosion, and abnormalities of the diaphragma sellae. In this preliminary series, we found Gd-MR to be promising for imaging adenomas; however, modifications in Gd-MR technique including thinner slices and immediate scanning after gadolinium injection are necessary for the best detection of focal lesions.