PT  - JOURNAL ARTICLE
AU  - Cross, D.J.
AU  - Flexman, J.A.
AU  - Anzai, Y.
AU  - Sasaki, T.
AU  - Treuting, P.M.
AU  - Maravilla, K.R.
AU  - Minoshima, S.
TI  - In Vivo Manganese–MR Imaging of Calcium Influx in Spontaneous Rat Pituitary Adenoma
AID  - 10.3174/ajnr.A0693
DP  - 2007 Nov 01
TA  - American Journal of Neuroradiology
PG  - 1865--1871
VI  - 28
IP  - 10
4099  - http://www.ajnr.org/content/28/10/1865.short
4100  - http://www.ajnr.org/content/28/10/1865.full
SO  - Am. J. Neuroradiol.2007 Nov 01; 28
AB  - BACKGROUND AND PURPOSE: Rapid uptake of the calcium analog manganese (Mn2+) into spontaneous pituitary adenoma during MR imaging of aged rats generated the hypothesis that neuroendocrine tumors may have a corresponding increase in calcium influx required to trigger hormonal release. A goal of this study was to investigate the potential for clinical evaluation of pituitary adenoma by MR imaging combined with administration of Mn2+ (Mn-MR imaging).MATERIALS AND METHODS: Mn-MR imaging was used to characterize the dynamic calcium influx in normal aged rat pituitary gland as well as spontaneous pituitary adenoma. To confirm the validity of Mn2+ as a calcium analog, we inhibited Mn2+ uptake into the olfactory bulb and pituitary gland of normal rats by using the calcium channel blocker verapamil. Rats with adenomas received fluorodeoxyglucose–positron-emission tomography (FDG-PET) scanning for characterization of tumor metabolism. Mn2+ influx was characterized in cultured pituitary adenoma cells.RESULTS: Volume of interest analysis of the normal aged pituitary gland versus adenoma indicated faster and increased calcium influx in adenoma at 1, 3, 11, and 48 hours. Mn2+ uptake into the olfactory bulb and pituitary gland of normal rats was inhibited by calcium channel blockers and showed dose-dependent inhibition on dynamic MR imaging. FDG-PET indicated correlation between tumor energy metabolism and Mn2+ influx as well as tumor size.CONCLUSION: These results indicate that adenomas have increased activity-dependent calcium influx compared with normal aged pituitary glands, suggesting a potential for exploitation in the clinical work-up of pituitary and other neuroendocrine tumors by developing Mn-MR imaging for humans.