Improvement of MRI-functional measurement with automatic movement correction in native and transplanted kidneys

Purpose: To improve 2D software for motion correction of renal dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and to evaluate its effect using the Patlak-Rutland model.Material and methods: A subpixel accurate method to correct for kidney motion during DCE-MRI was evaluated on native and transplanted kidneys using data from two different institutions with different magnets and protocols. The Patlak-Rutland model was used to calculate Glomerular Filtration Rate (GFR) on a voxel-by-voxel basis providing mean ( Kp) and uncertainty (Sigma_Kp) values for GFR. Results: In transplanted kidneys, average absolute variation of Kp was 6.4 %±4.8 % (max= 16.6 %). In native kidneys average absolute variation of was 12.11 % ±6.88 % (max= 25.6 %) for the right and 11.6 % ± 6 % (max= 20.8 %) for the left. Movement correction showed an average reduction of Sigma_Kp of 6.9 %±6.6 % (max= 21.4 %) in transplanted kidneys, 30.9 %±17.6 % (max= 60.8 %) for the right native kidney and 31.8 %±14 % (max= 55.3 %) for the left kidney. Conclusion: The movement correction algorithm showed improved uncertainty on GFR computation for both native and transplanted kidneys despite different spatial resolution from the different MRI systems and different levels of signal-to-noise ratios on DCE-MRI.