Diagnostic Performance of Different b-values in Diffusion- Weighted MRI for the Characterization of Focal Liver Lesions in Gaza Strip Governmental Hospitals

Abstract

Objective: To evaluate the diagnostic performance of apparent diffusion coefficient (ADC) mapping for differentiating benign and malignant focal liver lesions (FLLs) using different diffusion-weighted imaging (DWI) b-values.

Methods and Materials: A retrospective cross-sectional study was conducted among 51 consecutive patients with FLLs at Al-Shifa Medical Complex and European Gaza Hospital between March 2019 and December 2020. Patients underwent 1.5-T magnetic resonance imaging (MRI) with diffusion-weighted imaging using three b-values (0, 500, and 1000 s/mm²). Quantitative ADC measurements were obtained by manually placing regions of interest (ROIs) within the solid components of lesions. Statistical analysis was performed using MedCalc version 19.0.4, including receiver operating characteristic (ROC) curve analysis.

Results: Quantitative ADC values were significantly higher in benign FLLs compared with malignant lesions at both b = 500 and b = 1000 s/mm² (p < 0.05). At b = 500 s/mm², benign lesions showed a mean ADC value of 2.25 ± 0.50 × 10⁻³ mm²/s, whereas malignant lesions showed a mean value of 1.16 ± 0.17 × 10⁻³ mm²/s. At b = 1000 s/mm², mean ADC values were 1.25 ± 0.52 × 10⁻³ mm²/s for benign lesions and 0.83 ± 0.17 × 10⁻³ mm²/s for malignant lesions. ROC analysis demonstrated that an ADC cutoff value of 1.4 × 10⁻³ mm²/s at b = 500 s/mm² achieved 99% sensitivity and 85.9% specificity, while an ADC cutoff value of 1.1 × 10⁻³ mm²/s at b = 1000 s/mm² yielded 95.7% sensitivity and 84.5% specificity.

Conclusion: ADC mapping provides quantitative imaging biomarkers that may improve the differentiation of benign and malignant focal liver lesions. Standardized ADC cutoff values may enhance diagnostic confidence and support clinical decision-making in the characterization of liver lesions.