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Abstract: SA-PO1090

Noninvasive Evaluation of Renal Allograft Fibrosis Using Magnetization Transfer Imaging

Session Information

Category: Transplantation

  • 2102 Transplantation: Clinical

Authors

  • Al Saeedi, Mina H., Mayo Clinic Research Rochester, Rochester, Minnesota, United States
  • Gandhi, Deep, Mayo Clinic Research Rochester, Rochester, Minnesota, United States
  • Jiang, Kai, Mayo Clinic Research Rochester, Rochester, Minnesota, United States
  • Lerman, Amir, Mayo Clinic Research Rochester, Rochester, Minnesota, United States
  • Glockner, James, Mayo Clinic Research Rochester, Rochester, Minnesota, United States
  • Stegall, Mark D., Mayo Clinic Research Rochester, Rochester, Minnesota, United States
  • Kukla, Aleksandra, Mayo Clinic Research Rochester, Rochester, Minnesota, United States
  • Lerman, Lilach O., Mayo Clinic Research Rochester, Rochester, Minnesota, United States
Background

Fibrosis negatively affects kidney allograft survival, but the options for early noninvasive diagnosis are limited. Magnetic transfer imaging (MTI) magnetic resonance imaging (MRI) assesses tissue macromolecule accumulation (like collagen), a characteristic of fibrosis. We tested the hypothesis that MTI non-invasively detects allograft fibrosis in patients with KT.

Methods

Multiparametric MRI was performed in 13 (M9/F4) KT recipients with stable kidney function prior to the protocol allograft biopsy (Table 1). Cortical and medullary magnetization transfer ratio (MTR) at 1.5T MRI, oxygenation (blood oxygen level-dependent MRI), perfusion (arterial spin labeling), and microstructure (diffusion-weighted imaging) were compared with interstitial fibrosis (IF) on the kidney biopsy (trichrome staining) and with albumin-to-creatinine ratio (ACR). Glomerular filtration rate (GFR) was measured using iothalamate clearance.

Results

MTR correlated directly with both cortical and medullary histological IF and with ACR (Figure-1) but not with GFR. No other imaging-derived index correlated with any renal parameter.

Conclusion

Both the % of IF on kidney biopsy and ACR correlated significantly with MTR-MRI but not with any other MRI indices. Hence, MTR may provide a noninvasive tool for the detection and assessment of IF in renal allografts, pending confirmation in a larger number of patients.

Patient demographics (mean±standard deviation or median (min, max))
ParameterTotal
Post-transplant, Yrs.4 (4,7)
Age, Yrs,58 ± 12
MRI-kidney biopsy interval, days1 (1,41)
Cortical fibrosis (%)9.9 (6.3,41.8)
Medullary fibrosis (%)17.3 ± 9.7
Mean arterial pressure, mmHg100 ± 12
Serum creatinine, mg/dl2 ± 1
Iothalamate clearance, ml/min/BSA53 ± 18
Albumin/creatinine ratio, mg/g14 (3,102)

MRI=magnetic resonance imaging; BSA=body surface area.

Funding

  • NIDDK Support