Cardiac-Gated Diffusion-Weighted Magnetic Resonance Imaging Assessment of Kidney Function in Patients With Kidney...

Area of Science:

• Nephrology
• Radiology
• Biomedical Engineering

Background:

• Serum creatinine-based estimated glomerular filtration rate (eGFR) has limitations in accuracy due to factors like muscle wasting and inflammation, particularly in kidney cancer patients.
• Accurate assessment of split renal function (SRF) is critical for surgical planning, but traditional methods like eGFR are insufficient.
• Measured GFR (mGFR) using 99mTc-DTPA is the gold standard but involves lengthy procedures and radioactivity; kidney volume measurements offer functional proxies but not tissue quality insights.

Purpose of the Study:

• To evaluate advanced quantitative diffusion-weighted (DW) magnetic resonance (MR) imaging (MRI) metrics as potential surrogates for assessing kidney function.
• To correlate MR imaging parameters with measured GFR (mGFR) and estimated GFR (eGFR) in patients with renal masses.
• To assess the ability of MR metrics to differentiate proteinuria status.

Main Methods:

• A cohort of 27 patients with renal masses underwent advanced 3.0 T quantitative DW MRI, including cardiac-gated diffusion tensor imaging (DTI) and intravoxel incoherent motion (IVIM) analysis.
• Kidney volume measurements were also obtained.
• MR metrics were correlated with eGFR and mGFR using Pearson correlations and mixed-model analysis, respectively; LASSO regression predicted mGFR, and t-tests compared metrics between proteinuria groups.

Main Results:

• Kidney volume showed significant correlation with split renal function (split mGFR r = 0.54; split mGFRt r = 0.69).
• Advanced MR metrics demonstrated strong correlations with individual kidney mGFR and mGFRt (r = 0.76 and 0.81, respectively).
• Mixed-effects LASSO regression models accurately predicted mGFR and mGFRt (R² = 0.880 and 0.700, respectively), and MR metrics differentiated proteinuria status.

Conclusions:

• Advanced quantitative DW MRI metrics show potential as non-invasive surrogates for assessing mGFR in patients with renal masses.
• These MR parameters may also serve as indicators for proteinuria, offering valuable clinical information.
• Specific parameters derived from diastolic and systolic flow compensation were particularly informative for evaluating kidney function.