Neurohypophysis NMR Signal Anomalies

Abstract

Hypothalamic or central diabetes insipidus (HD or CDI) is a heterogeneous condition characterized by polydipsia and polyuria due to deficient arginine vasopressin (AVP) synthesis from the supraoptic and paraventricular nuclei of the hypothalamus and/or secretion from the neurohypophysis which have been stored as a complex with neurophysin (NP). Over one third of CDI cases are classified as idiopathic. Absence of the physiological neurohypophyseal hyperintense signal or bright spot on sagittal T1-weighted magnetic resonance imaging (MRI) is a common feature of all cases of CDI. The finding of a thickened infundibulum or pituitary stalk (or both), although not specific, suggests the presence of an infiltrative disease. We investigated the clinical presentation, morphologic characteristics of the pituitary region on MRI and the size of the pituitary stalk over time in two young girls who both later developed another hormone deficiency.