Whole-tumor apparent diffusion coefficient measurements in nephroblastoma: Can it identify blastemal predominance?

Area of Science:

• Radiology
• Pediatric Oncology
• Medical Imaging

Background:

• Nephroblastoma (Wilms tumor) is a common pediatric kidney cancer.
• Accurate histopathological subtyping is crucial for treatment stratification.
• Diffusion-weighted MRI offers non-invasive insights into tumor tissue characteristics.

Purpose of the Study:

• To investigate the correlation between whole-tumor apparent diffusion coefficient (ADC) parameters and histopathological findings in nephroblastoma.
• To assess the potential of ADC measurements to differentiate between tumor subtypes before and after neoadjuvant chemotherapy.

Main Methods:

• Diffusion-weighted MRI was performed on 52 children with nephroblastoma before chemotherapy and on 25 post-chemotherapy.
• Whole-tumor ADC values were measured, excluding non-enhancing areas.
• Associations between ADC parameters and histological subtypes were analyzed using correlation coefficients and ROC curves.

Main Results:

• The 25th percentile ADC at presentation showed a significant negative correlation with the proportion of blastema (r = -0.303, P = 0.026).
• Post-chemotherapy ADC demonstrated a moderate positive correlation with the stromal subtype (r = 0.579, P = 0.002).
• Median ADC of 1.362 × 10^-3 mm²/s optimally identified the stromal subtype with 100% sensitivity and 78.9% specificity.

Conclusions:

• Apparent diffusion coefficient (ADC) parameters in nephroblastoma are associated with stromal subtype histopathology.
• Whole-tumor ADC measurements may aid in identifying the stromal component but are likely insufficient for detecting blastema-predominant tumors.