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Updated: Aug 29, 2026

Non-invasive Imaging of Acute Allograft Rejection after Rat Renal Transplantation Using 18F-FDG PET
Published on: April 28, 2013
Measurement of renal extraction fraction using contrast-enhanced computed tomography
Graham Sommer1, Lawrence Chow, Norbert Pelc
1Department of Radiology, Stanford University School of Medicine, Stanford, California 94305, USA. gsommer@stanford.edu
Abstract:
Renal extraction fraction (EF) is the percentage of plasma entering the glomerulus which is filtered. Contrast agents which are freely filtered and neither secreted nor reabsorbed, may be used as markers for renal filtration, allowing EF to be calculated from computed tomography (CT) measurements of systemic vessels and renal veins. CT scans of 10 adult patients having no known renal disease were studied in this manner, giving EF values averaging 12.6% and 12.3% for the right and left kidneys, respectively, compared to the accepted value of 15%-20%. EF measurement using CT may provide noninvasive evaluation of renal function, complementing CT-derived morphologic information.
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