Paper

Imaging Renal Urea Handling in Rats at Millimeter Resolution using Hyperpolarized Magnetic Resonance Relaxometry

Verkman, Alan S, Cornelius von Morze, Lustig, Michael, Chaumeil, Myriam M, Ronen, Sabrina M, Vigneron, Daniel B, Wang, Zhen J, Kurhanewicz, John, Larson, Peder E Z, Jan Henrik Ardenkjær Larsen, Sands, Jeff M, Reed, Galen D, Koelsch, Bertram L

2015

Overview

In vivo spin spin relaxation time (\\(T_2\\)) heterogeneity of hyperpolarized 13C urea in the rat kidney was investigated. Selective quenching of the vascular hyperpolarized 13C signal with a macromolecular relaxation agent revealed that a long-\\(T_2\\) component of the 13C urea signal originated from the renal extravascular space, thus allowing the vascular and renal filtrate contrast agent pools of the 13C urea to be distinguished via multi-exponential analysis. The \\(T_2\\) response to induced diuresis and antidiuresis was performed with two imaging agents: hyperpolarized 13C urea and a control agent hyperpolarized bis-1,1-(hydroxymethyl)-1-13C-cyclopropane-\\(^2H_8\\). Large \\(T_2\\) increases in the inner-medullar and papilla were observed with the former agent and not the latter during antidiuresis suggesting that \\(T_2\\) relaxometry may be used to monitor the inner-medullary urea transporter (UT)-A1 and UT-A3 mediated urea concentrating process. Two high resolution imaging techniques - multiple echo time averaging and ultra-long echo time sub-2 mm\\(^3\\) resolution 3D imaging - were developed to exploit the particularly long relaxation times observed.

• Publisher: Cornell University Library, arXiv.org
• Subject: Contrast agents / Cyclopropane / Diuresis / Image resolution / Imaging techniques / Magnetic resonance / Relaxation time / Urea