Qualitative and quantitative performance of diffusion-weighted imaging in differentiation between benign and malignant soft tissue lesions

Introduction
MRI is the method of choice for the diagnostic workup of soft tissue lesions. Several studies have proved the ability of diffusion-weighted imaging (DWI) and apparent diffusion coefficients (ADC) to investigate the histological features of soft tissue tumors. However, its diagnostic potential is still questionable in avoiding unnecessary invasive maneuvers like biopsy or surgery owing to some overlapping characteristics between benign and malignant lesions.
Objective
The study aimed to evaluate the quantitative performance of the ADC and the qualitative performance of DWI in the differentiation between benign and malignant soft tissue lesions.
Patients and methods
A total of 50 patients with a histologically proof of newly diagnosed primary soft tissue tumors were retrospectively included in the study. All patients underwent MRI with DWI with sensitivities of values (50, 400, 800, and 1000 s/mm). ADC values of the solid components of these tumors were obtained and were correlated with the histopathological results.
Results
The mean ADC value of the benign soft tissue lesions was 1.52 × 10 mm/s, with a range of 0.4–2.6 × 10 mm/s, and for the malignant soft tissue lesions was 0.78 × 10 mm/s, with a range of 0.5–2.02 × 10 mm/s. The cutoff of mean ADC was 0.86 × 10 mm/s, which showed the highest specificity (97.22%) and accuracy (94.55%).
Conclusion
Using quantitative ADC value to standard MRI can improve the diagnostic accuracy of differentiating malignant and benign soft tissue lesions. It is considered as an attractive noninvasive diagnostic tool, except for myxoid and lipid-rich neoplasms, which showed an overlap of ADC values.