DIAGNOSTIC NEURORADIOLOGY Magnetic resonance imaging of the normal pituitary gland using ultrashort TE (UTE) pulse sequences (REV 1.0) Olivia Portman & Stephen Flemming & Jeremy P. D. Cox & Desmond G. Johnston & Graeme M. Bydder Received: 25 June 2007 / Accepted: 9 October 2007 / Published online: 22 November 2007 # Springer-Verlag 2007 Abstract Introduction The purpose of this study was to examine the normal pituitary gland in male subjects with ultrashort echo time (TE) pulse sequences, describe its appearance and measure its signal intensity before and after contrast enhancement. Methods Eleven male volunteers (mean age 57.1 years; range 36–81 years) were examined with a fat-suppressed ultrashort TE (=0.08 ms) pulse sequence. The studies were repeated after the administration of intravenous gadodi- amide. The MR scans were examined for gland morphol- ogy and signal intensity before and after enhancement. Endocrinological evaluation included baseline pituitary function tests and a glucagon stimulatory test to assess pituitary cortisol and growth hormone reserve. Results High signal intensity was observed in the anterior pituitary relative to the brain in nine of the 11 subjects. These regions involved the whole of the anterior pituitary in three subjects, were localised to one side in two examples and were seen inferiorly in three subjects. Signal intensities relative to the brain increased with age, with a peak around the sixth or seventh decade and decreasing thereafter. Overall, the pituitary function tests were considered to be within normal limits and did not correlate with pituitary gland signal intensity. Conclusion The anterior pituitary shows increased signal intensity in normal subjects when examined with T 1 - weighted ultrashort TE pulse sequences. The cause of this increased intensity is unknown, but fibrosis and iron deposition are possible candidates. The variation in signal intensity with age followed the temporal pattern of iron content observed at post mortem. No relationship with endocrine status was observed. Keywords Anterior pituitary . Magnetic resonance imaging . Signal level . Ultrashort echo time Introduction Magnetic resonance (MR) imaging is the technique of choice for examining the pituitary gland. On conventional T 1 -weighted spin echo images, the posterior pituitary gland has a high signal intensity relative to that of the brain. The cause of this increased intensity remains uncertain, but it has been linked to the presence of neurophysin and vasopressin and is directly related to function. A loss of signal is seen in patients with diabetes insipidus [1]. In the neonatal period and up to an age of 5–6 months, the anterior pituitary gland has a high signal intensity which is equal to that of the posterior pituitary when the gland is examined with T 1 -weighted sequences. After this time the signal intensity of the anterior pituitary gland becomes lower than that of the posterior pituitary and isointense with that of the white matter [1] or grey matter [2] in males, although a relative increase in signal intensity may be seen in pregnancy or during lactation. This latter phenomenon is generally attributed to hyperactive hormone secretion [3]. The pituitary gland has mainly been examined with two- dimensional (2D) spin echo sequences with echo times Neuroradiology (2008) 50:213–220 DOI 10.1007/s00234-007-0329-7 O. Portman : S. Flemming : J. P. D. Cox : D. G. Johnston Endocrinology and Metabolic Medicine, Imperial College Faculty of Medicine, St Mary’ s Hospital, Praed Street, London W2 1NY, UK G. M. Bydder (*) Department of Radiology, University of California, San Diego, 408 Dickinson Street, San Diego, CA 92103 8226, USA e-mail: gbydder@ucsd.edu