Diagnostic value of diffusion-weighted magnetic resonance imaging in differentiating benign and malignant fetal adrenal tumors

Objective: To evaluate diffusion-weighted imaging (DWI) and the apparent diffusion coefficient (ADC) for the prenatal differentiation of fetal adrenal neuroblastoma (NB) from benign masses. Methods: This retrospective study analyzed prenatal magnetic resonance imaging/DWI data from 54 pregnant women (59 adrenal masses) with a suspected solid adrenal mass on ultrasound. Cases with severe malformations or poor image quality were excluded. The minimum ADC (ADC min ), mean ADC (ADC mean ), and relative ADC (rADC) values within the tumor solid components were measured. Group comparisons and receiver operating characteristic (ROC) curve analysis were performed to assess the diagnostic performance. Results: Eighteen masses (30.5%) were classified as NB, while the remaining 41 (69.5%) were benign, including sequestration, hematoma, and teratoma. The NB group showed significantly greater gestational age at detection (mean age, 35 weeks), higher right adrenal prevalence (66.7%), and larger maximum diameters (3.6 cm vs. 2.4 cm; P < 0.01) compared to the non-NB group. The ADC min , ADC mean , and rADC were significantly lower in the NB group ( P < 0.001). ROC analysis identified ADC min as the optimal diagnostic parameter (area under the curve = 0.981). An ADC min threshold of 1382 μm 2 /s yielded 97.56% sensitivity and 100% specificity. Conclusion: These findings indicate that the quantitative DWI parameter ADC min can reliably differentiate fetal adrenal NB from benign lesions prenatally. Its high sensitivity and specificity may provide an objective basis for clinical decisions and optimized perinatal management.