Functional evaluation of secondary renal amyloidosis with diffusion-weighted MR imaging

Area of Science:

• Nephrology
• Radiology
• Medical Imaging

Background:

• Secondary renal amyloidosis (AN) poses diagnostic challenges.
• Accurate differentiation from other chronic kidney diseases (CKD) is crucial for effective management.
• Non-invasive diagnostic methods are highly desirable.

Purpose of the Study:

• To evaluate the diagnostic efficacy of diffusion-weighted magnetic resonance imaging (DW-MRI) for secondary renal amyloidosis.
• To compare two apparent diffusion coefficient (ADC) measurement methods (region of interest indicators [ROIs] and whole renal parenchyma [WP]) in diagnosing AN.
• To assess the potential of DW-MRI to obviate the need for renal biopsy.

Main Methods:

• The study included 24 AN patients, 20 CKD patients, and 20 healthy volunteers (HV).
• ADC values were measured using both ROIs and WP methods.
• Statistical analysis was performed to compare diagnostic performance between groups and methods.

Main Results:

• The ROIs method significantly differentiated AN from CKD (p=0.007) and AN from HV (p<0.05).
• Both ROIs and WP methods differentiated AN from HV.
• The ROIs method achieved 79% sensitivity and 60% specificity in differentiating AN from CKD.
• ADC values were lower in AN patients with GFR > 60 mL/min compared to HV (p<0.01).

Conclusions:

• DW-MRI is a valuable non-invasive tool for diagnosing secondary renal amyloidosis.
• The ROIs method demonstrates superior sensitivity and specificity for assessing renal amyloidosis.
• DW-MRI diagnosis may eliminate the need for renal biopsy in AN cases.