Assessment of renal dysfunction with diffusion-weighted imaging: comparing intra-voxel incoherent motion (IVIM) with a mono-exponential model

Abstract

Background

Because renal dysfunction is a worldwide problem, accurate assessment is required for planning treatment and follow-up. Intra-voxel incoherent motion (IVIM) can isolate fast from slow water motion in well-perfused organs and may be helpful in assessing renal dysfunction.

Purpose

To determine the clinical value of IVIM in the assessment of renal dysfunction compared with a mono-exponential model.

Material and Methods

Fifty-four consecutive participants (mean age, 53.13 ± 13.96 years) were recruited into this study. The estimated glomerular filtration rate (eGFR) was calculated to classify the participants as having severe renal injury (sRI, eGFR ≤ 30 mL/min/1.73 m²) or not (non-sRI). DWI with seven b-factors was performed. Image analysis was performed by a radiologist to generate an apparent diffusion coefficient map (ADC_mon) by mono-exponential model, diffusion coefficient (D_slow and D_fast), and fraction of fast diffusion (F_fast) maps by IVIM. The circular regions of interest were placed at the interface between the cortex and medulla for parameter measurements.

Results

The ADC_mon, D_slow, D_fast, and F_fast were less in sRI than non-sRI (P < 0.05). ADC_mon and D_slow were positively related with eGFR (P < 0.05). For differentiating sRI from non-sRI, receiver operating characteristic curve indicated no significant difference between the two methods (P > 0.05). Furthermore, the correlation was 0.93 between ADC_mon and D_slow, followed by 0.57 between D_fast and F_fast, 0.48 between ADC_mon and D_fast, and 0.34 between ADC_mon and F_fast (P < 0.05).

Conclusion

The IVIM model contributed little to improving the assessment of renal dysfunction compared with a mono-exponential model.