title: The diagnostic value of fused positron emission tomography/computed tomography in the localization of adrenocorticotropin-secreting pituitary adenoma in Cushing's disease.
abstract: Despite the high resolution of magnetic resonance imaging (MRI) of the pituitary gland, up to 40% of cases of Cushing's disease (CD) have normal MRI. Fused images of positron emission tomography and computed tomography (PET-CT) may have a potential diagnostic role in CD in general and in such cases in particular. Objective of this study is to explore the diagnostic potential of PET-CT for localization of adrenocorticotropin-secreting pituitary adenomas in CD. PET-CT was performed in 12 cases with de novo (7 cases) or persistent CD (5 cases) that were proven to have CD on biochemical, radiological and/or histopathological findings. These cases had a definite CD confirmed on histopathological and immunostaining examination of the subsequent transphenoidal surgical specimens (10 cases) and/or bilateral inferior petrosal sinus sampling (IPSS, 4 cases). PET-CT was positive in 7 of the 12 cases of CD (58%) showing a focal area of uptake in the pituitary gland. In these seven cases, MRI was positive in six (85.7%) but negative in one case (14.3%). In the other five cases with negative PET-CT, MRI was positive in two and negative in three cases. Of four cases with negative MRI, PET-CT was positive in one case (25%). We conclude that PET-CT is positive in around 60% of the cases of CD. Although the majority of cases with positive PET-CT had positive MRI, PET-CT may detect some cases with negative MRI and thus provides important diagnostic information. If these findings are confirmed in larger studies, PET-CT might become an important diagnostic technique, especially when the more invasive and technically demanding procedure of IPSS is not available or inconclusive.
authors.affiliation: Department of Medicine (MBC-46), King Faisal Specialist Hospital and Research Centre, P.O. Box 3354, Riyadh, 11211, Saudi Arabia. aliz@kfshrc.edu.sa
authors.forename: Ali S
authors.initials: AS
authors.lastname: Alzahrani
authors.forename: Rafif
authors.initials: R
authors.lastname: Farhat
authors.forename: Abdullah
authors.initials: A
authors.lastname: Al-Arifi
authors.forename: Nora
authors.initials: N
authors.lastname: Al-Kahtani
authors.forename: Imad
authors.initials: I
authors.lastname: Kanaan
authors.forename: Mohei
authors.initials: M
authors.lastname: Abouzied
mesh_terms: D049913:ACTH-Secreting Pituitary Adenoma / Q000175:diagnosis* / Q000473:pathology; D000328:Adult; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D047748:Pituitary ACTH Hypersecretion / Q000209:etiology / Q000473:pathology*; D010902:Pituitary Gland / Q000378:metabolism / Q000473:pathology; D049268:Positron-Emission Tomography / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*