EDUCATION EXHIBIT 93 T1 Signal Hyperin- tensity in the Sellar Region: Spectrum of Findings 1 LEARNING OBJECTIVES FOR TEST 4 After reading this article and taking the test, the reader will be able to: � Recognize normal entities with T1 hy- perintensity in the sellar region. � Identify sellar and parasellar lesions that exhibit high T1 sig- nal intensity. � Describe the spe- cific sources of T1 hyperintensity after surgery or medical therapy. Fabrice Bonneville, MD ● Franc ¸oise Cattin, MD ● Kathlyn Marsot-Dupuch, MD ● Didier Dormont, MD ● Jean-Franc ¸ois Bonneville, MD ● Jacques Chiras, MD T1 signal hyperintensity is a common finding at magnetic resonance imaging of the sellar region. However, this signal intensity pattern has different sources, and its significance depends on the clinical context. Normal variations in sellar T1 signal hyperintensity are related to vaso- pressin storage in the neurohypophysis, the presence of bone marrow in normal and variant anatomic structures, hyperactive hormone secre- tion in the anterior pituitary lobe (eg, in newborns and pregnant or lac- tating women), and flow artifacts and magnetic susceptibility effects. Pathologic variations in T1 signal hyperintensity may be related to clotting of blood (in hemorrhagic pituitary adenoma, pituitary apo- plexy, Sheehan syndrome, or thrombosed aneurysm) or the presence of a high concentration of protein (Rathke cleft cyst, craniopharyngioma, or mucocele), fat (lipoma, dermoid cyst, lipomatous meningioma), calcification (craniopharyngioma, chondroma, chordoma), or a para- magnetic substance (manganese, melanin). After treatment, T1 signal hyperintensity may result from the presence of materials used for surgi- cal packing (gelatin sponge, fat); from compression of the cavernous sinus and reduction of the venous flow, caused by overpacking of the operative bed; or from hormone hypersecretion by a remnant of nor- mal tissue in the anterior lobe of the pituitary gland. © RSNA, 2006 RadioGraphics 2006; 26:93–113 ● Published online 10.1148/rg.261055045 ● Content Codes: 1 From the Department of Neuroradiology, Pitie ´-Salpe ˆtrie `re Hospital, 74 Boulevard de l’Ho ˆ pital, 75013 Paris, France (F.B., D.D., J.C.); Department of Neuroradiology, Jean Minjoz Hospital, Besanc ¸on, France (F.C., J.F.B.); and Department of Neuroradiology, Bice ˆtre Hospital, Le Kremlin-Bice ˆtre, France (K.M.). Recipient of an Excellence in Design award for an education exhibit at the 2004 RSNA Annual Meeting. Received March 7, 2005; revision requested April 12 and received May 4; accepted May 5. All authors have no financial relationships to disclose. Address correspondence to F.B. (e-mail: fabrice.bonneville@psl.ap-hop-paris.fr). © RSNA, 2006 CME FEATURE See accompanying test at http:// www.rsna.org /education /rg_cme.html RadioGraphics See last page TEACHING POINTS Note: This copy is for your personal non-commercial use only. To order presentation-ready copies for distribution to your colleagues or clients, contact us at www.rsna.org/rsnarights.