Normal and abnormal pituitary glands: gadopentetate dimeglumine-enhanced MR imaging.

Abstract

Dynamic magnetic resonance (MR) imaging with a 1.5-T superconductive unit was used in the evaluation of nine normal pituitary glands and 10 pituitary adenomas, including four microadenomas and six macroadenomas. Seven to 10 images were obtained every 20-30 seconds with use of the spin-echo technique after rapid injection of gadopentetate dimeglumine. The earliest contrast material enhancement of normal structures was seen in the infundibulum and posterior lobe of the pituitary gland at 20 seconds, followed by gradual contrast material enhancement of the anterior lobe of the pituitary gland from the junction of the infundibulum to the peripheral portion of the anterior lobe of the pituitary gland within 80 seconds after gadopentetate dimeglumine injection. The peak enhancement of pituitary adenomas occurred at 60-200 seconds, usually after the most marked enhancement of the normal pituitary gland. Microadenomas are best visualized at earlier phases of gadopentetate dimeglumine-enhanced dynamic imaging, with signal intensity lower than that seen on images of normal pituitary glands.

Evaluation of Diffusivity in the Anterior Lobe of the Pituitary Gland: 3D Turbo Field Echo with Diffusion-Sensitized Driven-Equilibrium Preparation

“…We suspect that the lack of myelination and hypervascularity in the normal pituitary gland may contribute to the increased diffusivity compared with the pons and vermis. 18,19 Further studies are needed to investigate this possibility.…”

Gamma Knife Radiosurgery for Functioning Pituitary Adenomas

“…True sensitivity of various techniques in the detection of microadenomas is estimated at about 85±90% for contrast-enhanced MR imaging. The actual tumor margin can be obscure on dynamic MRI by the timing of enhancement and susceptibility artifact [14,15], so broad coverage of the tumor on imaging for radiosurgery could result in earlier hormonal normalization. It is contended that measurement of the prescription isodose volume gives a better indication of coverage than the target volume, because of the inherent difficulties in drawing the target accurately.…”

Usefulness of the dynamic gadolinium-enhanced magnetic resonance imaging with simultaneous acquisition of coronal and sagittal planes for detection of pituitary microadenomas

“…In the dynamic gadolinium-enhanced MR imaging of pituitary glands, contrast enhancement has been estimated to occur in the following order described in previouslypublished papers: posterior lobe, stalk, anterior lobe, because a normal posterior pituitary lobe receives direct arterial blood supply from the inferior hypophyseal arteries; the stalk is supplied from the superior hypophyseal arteries; and the anterior lobe is supplied from the superior hypophyseal arteries indirectly through the pituitary portal system [1][2][3][4][5].…”

“…Because pituitary adenomas gradually or rapidly enhance compared with normal anterior pituitary glands, they are detected more clearly in the early phase after injection of contrast material on dynamic contrast-enhanced MR imaging [1][2][3][4][5][6]. However, in the case of microadenomas that are small or located in the far anterior or the far posterior portions of glands, the lesions might be overlooked on MR images using only coronal imaging [7].…”