Purpose: To investigate the correlation between signal intensity of the posterior pituitary gland on magnetic resonance (MR) images and levels of plasma antidiuretic hormone (ADH) in patients undergoing hemodialysis.
Materials and methods: The cases of 25 patients undergoing hemodialysis (15 men and 10 women, aged 24-75 years [mean, 51 years]) were prospectively evaluated. Laboratory testing and MR imaging were performed both before and after hemodialysis in 14 patients and only before hemodialysis in 11 patients.
Results: Before hemodialysis, nine patients (36%) had normal hyperintensity in the posterior pituitary gland, with almost normal plasma ADH levels and slightly elevated plasma osmolality. In six patients (24%) with less hyperintensity than is characteristic in the posterior pituitary gland, plasma ADH levels were slightly increased or normal. In 10 patients (40%) with an isointense posterior pituitary gland, plasma ADH and osmolality levels were evaluated.
Conclusion: Elevated plasma osmolality may cause increased plasma ADH concentration and a lack of hyperintensity in the posterior pituitary gland at MR imaging.