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Abstract: TH-PO916

Assessment of MRI Filtration Fraction in Healthy Subjects and Patients with Diabetic Kidney Disease

Session Information

Category: Diabetic Kidney Disease

  • 602 Diabetic Kidney Disease: Clinical

Authors

  • Johansson, Lars, Antaros Medical, Molndal, Sweden
  • Hockings, Paul, Antaros Medical, Molndal, Sweden
  • Makvandi, Kianoush, Sahlgrenska University Hospital, Göteborg, Sweden
  • Jensen, Gert, Sahlgrenska University Hospital, Göteborg, Sweden
  • Unnerstall, Tim, Sahlgrenska University Hospital, Göteborg, Sweden
  • Leonhardt, Henrik, Sahlgrenska University Hospital, Göteborg, Sweden
  • Jarl, Lisa, Antaros Medical, Molndal, Sweden
  • Englund, Camilla, Antaros Medical, Molndal, Sweden
  • Erlandsson, Fredrik, AstraZeneca, Gaithersburg, Maryland, United States
  • Sundgren, Anna K., AstraZeneca, Gaithersburg, Maryland, United States
  • Hulthe, Johannes, Antaros Medical, Molndal, Sweden
  • Baid-Agrawal, Seema, Sahlgrenska University Hospital, Göteborg, Sweden
Background

Filtration fraction (FF) is the ratio of the glomerular filtration rate (GFR) to renal plasma flow (RPF) and therefore an important marker of glomerular health. FF is not normally measured, as estimation of RPF requires constant infusion of para-aminohippurate over 8 h (1). Therefore, quicker, simpler assays of FF are needed.
We assessed a novel magnetic resonance imaging (MRI) technique to measure FF in patients with diabetic kidney disease (DKD). MRI was previously used to measure FF in kidney donors (2,3).

Methods

The study included 2 CKD2, 16 CKD3, and 20 CKD4 patients with DKD, 18-79 years old, eGFR between 15-60 ml/min/1.73 m2 and 20 age-, gender-matched healthy controls. GFR was measured using iohexol clearance (mGFR). Renal blood flow (RBF) (ml/min) was measured by phase contrast MRI. The phase contrast MRI scan is a 5 minutes add-on to an MRI examination.

MRI FF = (mGFR x BSA)/(RBF x 1.73)

RBF was corrected for Body Surface Area (BSA) to use the same units as GFR. EVF (hematocrit) was not available and therefore RPF was not calculated.

Results

MRI FF % (Mean (SD)) was 8.28 (1.00)% for Healthy Controls; 6.57 (2.62) % for CKD2; 6.30 (0.93)% for CKD3; and 5.15 (1.36)% for CKD4.
We tested for significant differences between groups (p 0.05) using Bonferroni/Dunn multiple testing correction. p-values less than 0.008 were significant. Differences in FF in controls vs both CKD3 and CKD4 (p < 0.0001), and CKD3 vs CKD4 (p 0.005) were significant.

Conclusion

Standard deviations in the CKD 2 group were relatively large as there were only 2 subjects in this group. All MRI FF comparisons between control subjects, CKD3 subjects and CKD4 subjects were statistically significant. This MRI FF measurement can be further improved by correcting RBF for extracellular volume in order to calculate RPF.
References 1) Costanzo L (2007) Physiology. Lippincott Williams and Wilkins, Philadelphia; 2) Eikefjord, et al AJR (2016) 207, 1022-1030; 3) Cutajar, et al. Eur Radiol (2015) 25: 2390.

Funding

  • Commercial Support