Dynamic three-dimensional MR renography for the measurement of single kidney function: initial experience

Area of Science:

• Radiology
• Nephrology
• Medical Imaging

Background:

• Assessing kidney function, including glomerular filtration rate (GFR) and split renal function, is crucial for diagnosing and managing renal diseases.
• Traditional methods like technetium 99m (99mTc) diethylenetriaminepentaacetic acid (DTPA) clearance are established but involve radionuclide exposure.
• There is a need for non-invasive imaging techniques that can accurately quantify renal function.

Purpose of the Study:

• To develop and validate a three-dimensional magnetic resonance (MR) renographic method for measuring single kidney glomerular filtration rate (GFR) and split renal function.
• To evaluate the correlation of MR renography with a standard radionuclide method (99mTc-DTPA).

Main Methods:

• A three-dimensional MR renographic technique was developed utilizing renal signal intensity measurements.
• A low dose (2 mL or 0.01 mmol/kg) of gadopentetate dimeglumine was intravenously injected.
• Measurements were taken 2-3 minutes post-injection, alongside contrast-enhanced MR imaging of kidneys and renal arteries.

Main Results:

• Single kidney MR GFR indices showed good correlation with 99mTc-DTPA clearance (r = 0.7-0.8) for GFR values ranging from 7-48 mL/min.
• MR right kidney split renal function values (32%-59%) correlated well with 99mTc-DTPA measurements (r = 0.76), with minimal average difference (0.8% +/- 8).
• The MR renography procedure added 8 minutes or less to the total examination time.

Conclusions:

• Three-dimensional MR renography is a feasible and accurate method for assessing single kidney GFR and split renal function.
• This MR-based technique offers a non-invasive alternative to radionuclide methods, with comparable diagnostic performance.
• The method is efficient, minimally increasing examination time, and uses a low dose of gadolinium contrast.