Nathan Artz, Presenter: Nothing to Disclose

Elizabeth A. Sadowski MD, Abstract Co-Author: Nothing to Disclose

Andrew Louis Wentland BS, Abstract Co-Author: Nothing to Disclose

Thomas Martin Grist MD, Abstract Co-Author: Speaker, General Electric Company Advisory Board, Bayer AG Consultant, Bracco Group Speaker, Bracco Group

Arjang Djamali MD, Abstract Co-Author: Nothing to Disclose

Sean B. Fain PhD, Abstract Co-Author: Research grant, General Electric Company Research Consultant, Marvel Medtech, LLC

Due to the link between gadolinium-based contrast agents and Nephrogenic Systemic Fibrosis (NSF), non-contrast methods of evaluating renal perfusion are of increased importance and may be helpful for assessing transplant function. This work examines intra-day and inter-day reproducibility of cortical perfusion measurements using a pulsed ASL method (FAIR-FIESTA) in native and transplanted kidneys over a broad range of renal function.

We recruited 10 native subjects and 14 transplant subjects representing a range of renal function. For the inter-day data, two MR examinations using the pulsed ASL sequence were performed at least 24 hours apart and the estimated glomerular filtration rate (eGFR) was measured each day just prior the MR scanning session. Perfusion measurements were also repeated on the same day for 8 native subjects and 13 transplanted subjects. On a 1.5 T MR system, ASL cortical perfusion images were acquired using a FAIR-FIESTA technique and analyzed assuming a one compartment model. Following automated normalized mutual information (NMI) registration, the cortex of the kidney was segmented out. ASL perfusion measurements over the cortex were averaged for each kidney. Percent difference was determined by using the measurement from the first exam as the reference measurement such that a lower perfusion measurement on the second exam corresponds to a negative percent difference.

Combining native and transplanted kidneys, cortical perfusion measurements demonstrated an average absolute percent difference of 5% for intra-day exams and 10% for inter-day exams. Native and transplant data exhibited similar inter-day percent difference distributions about zero, with the 95% confidence interval ranging from + 22% in natives and + 27% in transplants. Perfusion correlated to eGFR in both native (r = 0.80, p = 0.00004) and transplant kidneys (r = 0.57, p = 0.03).

Cortical perfusion measured by non-contrast pulsed ASL appears to be reproducible and correlates to eGFR in both native and transplanted kidneys. This technique may be useful for the longitudinal assessment of transplant function in future studies.

MR perfusion measurements may be more sensitive to nephron loss than current clinical parameters while also providing a non-invasive test to follow disease progression.

Artz, N, Sadowski, E, Wentland, A, Grist, T, Djamali, A, Fain, S, Non-Contrast Arterial Spin Labeling Approach to Kidney Perfusion: Assessing Reproducibility in Native and Transplanted Kidneys.  Radiological Society of North America 2009 Scientific Assembly and Annual Meeting, November 29 - December 4, 2009 ,Chicago IL. http://archive.rsna.org/2009/8016920.html