Assessment of Renal Physiology by Magnetic Resonance Imaging (MRI) in Normal Volunteers

Assessment of Renal Physiology (Glomerular Filtration Rate and Blood Flow) by MRI With Validation by Inulin and Para-Aminohippuric Acid Clearance in Normal Volunteers

Estimation of Glomerular Filtration Rate (GFR) is the primary test used to assess patients with renal disease. Although serum creatinine based GFR and nuclear medicine based estimations are routinely used in clinical practice, GFR estimation by Inulin is the recommended gold standard. Inulin based estimation of GFR is cumbersome and time consuming.

A decrease in blood flow to the kidney (Renal Blood Flow (RBF)) is known to cause a decrease in GFR. RBF is typically determined using radioactive tracers, contrast MRI or a cumbersome para-aminohippuric acid (PAH) clearance method.

MRI based assessment of GFR and RBF have been suggested to provide reasonable accuracy. Most of these studies did not compare the GFR and RBF estimation directly to Inulin and PAH clearance which are ther gold standards . In this study we propose to estimate MRI based GFR estimation directly to Inulin and noncontrast MRI based derived RBF to PAH to assess if MRI is an accurate test of kidney function.

Inclusion Criteria:

• Healthy male or female volunteers with no known renal disease
• Ages between 18-65 years
• Normal routine urinalysis
• Estimated GFR (eGFR) >=90mls/min
• Arterial pressure < 130/85
• No medications (birth control pills and vitamins are acceptable)

Exclusion Criteria:

• Pregnancy
• Age <18y or >65y
• Proteinuria or hematuria as determined by routine urinalysis
• Estimate GFR (eGFR) < 90 ml/min
• Known history or requirement of treatment for hypertension
• Known allergy to inulin or PAH
• MRI contrast allergy, general contraindications to MRI such as pacemaker, etc.