Intravoxel Incoherent Motion Magnetic Resonance Imaging in Partially Nephrectomized Kidneys.

Area of Science:

• Radiology and Imaging Science
• Nephrology and Urology
• Biomedical Engineering

Background:

• Solid renal masses often necessitate partial nephrectomy (PN), a procedure that impacts kidney function.
• Accurate assessment of individual kidney function is crucial for managing patients undergoing PN.
• Diffusion-weighted magnetic resonance imaging (DWI) offers a noninvasive method to evaluate tissue microstructure and function.

Purpose of the Study:

• To investigate the effects of partial nephrectomy (PN) on apparent diffusion coefficient (ADC) and intravoxel incoherent motion (IVIM) parameters in kidneys with solid renal masses.
• To assess the utility of quantitative DWI parameters as noninvasive biomarkers for single kidney function after PN.

Main Methods:

• Fifteen patients with renal masses underwent DWI before and 1 week after PN using a 3 T scanner.
• Apparent diffusion coefficients (ADCs) and IVIM parameters (f, Dslow, Dfast, PF) were calculated using monoexponential and biexponential models.
• Estimated glomerular filtration rate (eGFR) was calculated using the Modification of Diet in Renal Disease (MDRD) formula.

Main Results:

• Partially nephrectomized kidneys showed significantly lower ADC, f, and PF values compared to contralateral kidneys post-PN.
• A significant decrease in ADC, f, and PF was observed in partially nephrectomized kidneys from baseline to follow-up.
• Nonnephrectomized kidneys showed a significant increase in ADC and PF, while eGFR correlated positively with most DWI parameters in partially nephrectomized kidneys.

Conclusions:

• Quantitative DWI parameters, including ADC and IVIM-derived metrics, are highly indicative of renal function after PN.
• IVIM analysis provides additional insights into kidney physiology beyond standard ADC measurements.
• Quantitative DWI, especially perfusion-related IVIM parameters, holds significant potential as a noninvasive biomarker for single kidney function assessment.