Modeling Systemic and Renal Gadolinium Chelate Transport with MRI

John Votaw

This research aims to derive quantitative physiologic information from sequential MRI images following gadolinium chelate (Gd) infusion.  In this case, Renal blood flow and glomerular filtration rate.

The movie below shows 450 seconds following the infusion of Gd.  The Gd can be seen traveling down the aorta, into and through the kidneys, and then in the ureters as it progresses to the urinary bladder.

The concentration of Gd in the aorta and kidney are displayed graphically below.

These curves are interpreted with the aid of a kinetic model written in terms of partial differential equations.  By employing this model, renal blood flow and blood volume, capillary permeability, and the glomerular filtration rate can be determined.  A screen shot of the program in operation follows.

For this particular patient, the blood flow to the left kidney is only 3.8 ml/sec, which is about half of normal.  However, the GFR is 55 ml/min, which is in the normal range.  This is an example of a kidney under stress that may be susceptible to losing function in the future.

Conclusions
Rapid sequential MRI imaging can be used to accurately assess renal function in less than 5 minutes.