Measurement of renal perfusion may be a tool to assess the significance of renal artery stenosis and to assess ischemic nephropathy, and it may be used in renal transplant assessment. Several techniques have been studied to measure renal perfusion [1]. The maximum slope Gd-DTPA technique uses the maximum slope of the Gd-DTPA enhancement curve in relation to the maximum Gd-DTPA concentration in the aorta to calculate renal blood flow. The Gd-DTPA concentration in the aorta can be calculated using pre-contrast and post-contrast relaxation times measured in the aorta, assuming a linear relationship between gadolinium concentration and the inverse of the pre- and post-contrast T1 difference. Calibration of the signal intensity is performed using phantoms with increasing gadolinium concentration .
Furthermore, attempts have been made to assess renal perfusion by arterial spin labeling. To prevent leakage of the contrast medium into the extravascular space, albumin-bound contrast agent is used. However, the different MRI renal perfusion techniques still need to be validated so more research is needed to assess the clinical usefulness.
Source: http://www.ncbi.nlm.nih.gov/
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