Abstract: FR-PO667

Automatic Data Analysis for Standardization of Renal Diffusion Tensor MRI

Session Information

Category: Diabetes

  • 502 Diabetes Mellitus and Obesity: Clinical

Authors

  • Doenyas-Barak, Keren, Asaf-Harofhe MC, Zerifin, Israel
  • Efrati, Shai, Asaf-Harofhe MC, Zerifin, Israel
Background

Diffusion tensor MRI (DTI) noninvasively evaluates renal microstructure, especially fibrosis. DTI parameters and creatinine clearance have shown good correlation. However, neither a uniform technique for data analysis nor standard values exists. DTI is analyzed using manual selection of regions of interest (ROIs). Subjectivity of operator's interpretation and poor reproducibility limit the clinical value of this technique. We evaluated standard protocols for renal DTI quantification.

Methods

Twelve adults with diabetic kidney disease, defined as eGFR<60 ml/min/1.73m2 or proteinuria, and 5 healthy volunteers were scanned in a 3T Siemens scanner. Data were analyzed using 3 definitions of ROI:
Manual selection of ROI based on intensity: Four circle ROIs are placed on high and low signal intensity regions of the 4 anatomical slices to define the medulla and cortex, respectively.
Automatic ROI selection: The cortex was defined as 5-10 mm from the external margin of the kidney and the medulla as the region from the internal margin of the cortex to the inner margin of the kidney of 4 slices.
Fiber tracking: DTI fiber-tracking was performed on 4 coronal slices of the kidney medulla, reconstruction kidney fibrils. Fiber volume, calculated as a percent of the whole kidney volume, was extracted in 5 fractional anisotropy (FA) thresholds: 0.1-0.2.

Results

Mean age was 65.9 years (60.5-70.7) and mean eGFR 62.9 ml/min/1.73m2 (37.1-83.5). The mean cortical apparent diffusion coefficient (ADC) and FA were 0.0029(0.0026-0.0032) and 0.165(0.152-0.184) using manual ROI selection, and 0.0024 (0.0026-0.0029) and 0.175(0.172-0.196) using automatic selection. Respective values for medullary ADC and FA were 0.0028 (0.0026-0.0029) and 0.175(0.160-0.196); and 0.0022(0.0021-0.0034) and 0.023(0.126-0.182). A strong correlation with eGFR was demonstrated for medullary ADC and FA (r=0.748 and r=0.657 p<0.05) and for cortical ADC (r=0.617 p<0.05) using automatic ROI selection, but only for medullary FA using manual ROI selection (r=0.678 p<0.05). Fiber tracking at FA thresholds of 0.12, 0.15 and 0.17 showed a strong correlation with eGFR (r=0.783, 0.787, 0.712 p<0.05 for all).

Conclusion

Objective data analysis using anatomic ROIs or fiber tracking strongly correlate to renal function and may be used for standard analysis of renal DTI.