Relationship Between Hypothalamic-pituitary MRI And Central Diabetes Insipidus

Background and objectives:Central diabetes insipidus (CDI) is a syndrome characterized by polydipsia, polyuria, high output of hyposthenuria and low specific gravity of urine due to deficiency in synthesis and/or secretion of antidiuretic hormone(ADH). This disease can seriously impair children’s health. Poor night’s sleep and poor appetite without proper therapy can result in short stature, expansion of urinary system and secondary renal failure and influence lifetime of children. And CDI may be an early clinical manifestation of tumors of the hypothalamic-pituitary region. Therefore, magnetic resonance imaging (MRI) has an important value in the diagnosis of CDI. Neurosecretory granules of ADH are released by hypothalamic nudei and stored in the posterior lobe. Therefore, there is a high signal of posterior pituitary "bright spot" on MRI. The disappearance or reduction of the high signal of posterior pituitary " bright spot"on MRI is important for the diagnosis of CDI. CDI can be divided into primary CDI and secondary CDI according to different reasons. Primary CDI is caused by unknown reasons resulting in deficiency in ADH secreted by neurosecretory cells in hypothalamus. Secondary CDI is caused by various reasons of damage in hypothalamic-pituitary axis, such as tumors in saddle area (craniopharyngioma, germinoma, hypophysoma), langerhan cell tissue hyperplasia, empty sella turcica, pituitary hypoplasia, pituitary stalk interruption syndrome (PSIS), surgery, radiotherapy. In multiple pituitary hormone deficiency (MPHD), congenital factors, pituitary mass, damage of pituitary stalk, intracranial tumors or infection, craniocerebral trauma can result in CDI and other manifestations of deficiency in corresponding target of pituitary gland. In addition to growth hormone deficiency, there is one or more of the anterior and/or posterior pituitary deficiency in MPHD. In this study, we analyzed MRI manifestations, water deprivation and vasopressin tests, pituitary function, and treatment response of68children with CDI and investigated the relationship between MRI of the hypothalamic-pituitary region and central diabetes insipidus. Methods:1.Subjects:68children with CDI, aged (10.63±3.18) years. Etiological analysis were carried out according to MRI, water deprivation and vasopressin tests, and treatment response.2.MRI:Hypothalamic-pituitary MRI of all children was performed using3.0T MR scanner in the sagittal and coronal planes on T1WI and T2WI. The slice thickness was3mm. The contrastmedia was gadolinium-DTPA using dose of0.1mmol/kg. The contrast-enhanced MRI was done after contrastmedia. The pituitary morphology, height of anterior pituitary, location and size of posterior pituitary, morphology of pituitary stalk, other abnormalities of saddle.3.Laboratory tests:Fasting blood was collected from all CDI children at diagnosis. Thyroid stimulating hormone (TSH), free thyroxine (FT4), follicle stimulating hormone (FSH), luteinizing hormone (LH), estrodiol (E2), testosterone (To), prolactin (PRL), beta-human chorionic gonadotropin (β-HCG), alpha fetoprotein (AFP), growth hormone (GH), insulin-like growth factor1(IGF-1), and water deprivation and vasopressin tests.Results:1.In68children with CDI,18cases (14male) were postoperation of craniopharyngioma,15cases (14male) were completed PSIS without posterior pituitary " bright spot",15cases (13male) were PSIS with ectopic and approximately disappear posterior pituitary " bright spot",18cases had thicken pituitary stalk without posterior pituitary (8cases were germinoma,10cases were langerhan cell tissue hyperplasia),2cases were secondary nephrogenic diabetes insipidus.2.There were50cases who had various degree of MPHD.3.There were2cases with long medical history who had mental retardation, hydronephrosis, ureterectasia, bladder expanding. And Minirin treatment was not good until hydrochlorothiazide was added.Conclusions:1.Abnormalities in morphology of pituitary and surrounding can be found by MRI. Complete or partial disappearance in posterior pituitary combined with water deprivation and vasopressin tests are important for the diagnosis of CDI.2.In secondary CDI, tumors and PSIS are the main cause. Pituitary hormones and tumor markers should be considered for further confirmation. 3.In CDI patients with a long medical history, they may have renal complications, such as hydronephrosis, ureterectasia, bladder expanding. Treatment using Minirin combined with hydrochlorothiazide is better.