Gholam Reza Berenji MD, Presenter: Nothing to Disclose

Bradley A. Jabour MD, Abstract Co-Author: Nothing to Disclose

Edwin Glass MD, Abstract Co-Author: Nothing to Disclose

Although MRI and CT are widely employed in evaluating the sella, both methods provide limited contrast resolution for the detection of pituitary adenomas, particularly small adenomas. We have often observed bright uptake F-18FDG in these pituitary lesions, and therefore investigated the relationship of detection of adenomas by FDG PET and MRI/CT.

We retrospectively evaluated 40 patients (4 women and 36 men, mean age 66, age range 38-87) with known or suspected pituitary adenomas who underwent FDG PET during 1993-2006. Results of PET, MRI or CT were compared. All PET and MRI-CT scans were rated as (+) or (-) overall, and also by lesion size (4-scale as negative, small, medium, large). PET scans were further characterized by FDG uptake (0-4+). Concordance between PET and MRI-CT for size and uptake were evaluated using kappa and Fisher’s exact testing.

35/40 patients had MRI (28/35) or CT (7/35) studies out of whom 20 (57%) had positive pituitary findings by MRI or CT. Lesions were classified for size by MRI-CT and PET, with complete concordance for size (4 categories) in 51%, with kappa=0.346+-0.08, p<0.01. When categorized for concordance between MRI or CT size versus PET uptake however, a significantly lower concordance was observed between MRI or CT size and PET uptake (kappa=0.075+-0.07, p=NS). Alternatively, using 2 x 2 categorizations (MRI as negative/small or moderate-large, PET uptake as 0-2+ or 3-4+) a similar discordance was demonstrated using Fisher exact testing, p=0.009. These discordances between PET and MRI-CT findings were explained by the frequent occurrence of bright (3+ or 4+) FDG uptake in adenomas (in 45%) that were negative or small by MRI or CT. Four patients who had undergone previous pituitary resections had both (-) PET and (-) MRI or CT.

Pituitary adenomas are often distinctly identifiable in FDG PET images, which offer complimentary and additional information to that provided by MRI or CT. This characteristic offers potential clinical benefits in the diagnosis, management, and follow up of these pituitary lesions.

FDG PET can potentially be used as a complementary imaging method to CT and MRI for evaluation of pituitary adenomas.

Berenji, G, Jabour, B, Glass, E, FDG PET in the Detection of Pituitary Adenomas.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5007934.html