Gadolinium-DTPA-enhanced and digitally subtracted magnetic resonance imaging of estrogen-induced pituitary lesions in rats: correlation with pituitary anatomy.
Pituitary hypertrophy and tumors were induced in male Sprague Dawley rats using estradiol-17 beta. This tumor model generates a variety of pituitary lesions which are relevant to human pituitary disease. In order to characterize these lesions, gadolinium DTPA was injected intravenously into the tail vein of estrogen treated and control rats. High resolution T1-weighted MR images, pre- and postenhancement, were obtained at 8 different time points spanning 300 days following the subcutaneous implantation of the estrogen pellets. Images with 2-mm slice thickness were made with a 2 Telsa small-bore MR imaging system. Both normal and tumorous pituitaries were found to enhance with contrast agent, but contrast uptake was not uniform. Gd-DTPA distribution was sensitive to the different types of lesions generated in the course of this study. Digital subtraction of congruent images, pre- and postcontrast, provided difference images reflecting contrast concentration and allowed identification of subtle enhancement effects. Hypertrophic pituitaries displayed uptake of contrast, but the distribution of contrast agent was nonuniform and appeared mottled. A bright rim enhancement was often seen anterior to the pituitary gland, most likely arising from the oculomotor nerves and arachnoid. Histological slices in the same anatomical plane as the MR images were obtained on the animals allowing identification of individual lesions. Cystic areas within tumors were found to give strong contrast enhancement in less than five min postinjection. Solid and hemorrhagic areas of the pituitary tumor were hypo- to isointense relative to surrounding brain and did not take up contrast agent. Significant perfusion in these areas apparently does not occur.(ABSTRACT TRUNCATED AT 250 WORDS)
van Nesselrooij
J H
JH
Department of Radiology, State University of New York, Syracuse 13210.
Szeverenyi
N M
NM
Tillapaugh-Fay
G M
GM
Hendriksen
F G
FG
D000818:Animals; D001921:Brain / Q000473:pathology; D003287:Contrast Media; D003560:Cysts / Q000473:pathology; D004958:Estradiol / Q000009:adverse effects*; D005682:Gadolinium; D019786:Gadolinium DTPA; D006470:Hemorrhage / Q000473:pathology; D006984:Hypertrophy; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009942:Organometallic Compounds; D004369:Pentetic Acid; D010902:Pituitary Gland / Q000473:pathology*; D010911:Pituitary Neoplasms / Q000139:chemically induced* / Q000473:pathology; D051381:Rats; D011919:Rats, Inbred Strains; D012815:Signal Processing, Computer-Assisted; D013382:Subtraction Technique
D003287:Contrast Media; D009942:Organometallic Compounds; D004958:Estradiol; D004369:Pentetic Acid; D005682:Gadolinium; D019786:Gadolinium DTPA