A critical analysis of the value of simultaneous inferior petrosal sinus sampling in Cushing's disease and the occult ectopic adrenocorticotropin syndrome. by Kaltsas, G, Giannulis, MG, Newell-Price, J, Dacie, J, Thakkar, C, Afshar, F, Monson, J, Grossman, AB, Besser, G, Trainer, P