Diffusion weighted MRI of soft tissue masses: Can measurement of ADC value help in the differentiation between benign and malignant lesions?

Abstract

Objective: To assess the ability of DWI & numerical ADC values associated with routine MRI in classification of different musculoskeletal soft tissue masses. Patient & method: 45 patients (32 females and 13 males) with known or clinically suspected to have musculoskeletal soft tissue masses were included. Their age ranging from (9–72) years, they all subjected to conventional MRI, DWI and ADC values were calculated, The diagnosis was confirmed by histologic biopsy. Results: Benign neoplasms (except for lipomas) showed values of ADC above 1.275 × 10−3 mm2/s while malignant soft tissue tumors (except for high-grade myxofibrosarcoma) have ADC values below 1.1 × 10−3 mm2/s. Mean ADC values for benign and malignant soft tissue tumors were 1.53 ± 0.91 mm2/s and 0.84 ± 0.33 mm2/s respectively with cutoff value 1.235 mm2/s showing sensitivity, specificity & accuracy 73%, 91.7% & 80.3% respectively. Tru cut biopsy done in (28) patients (8 benign & 20 malignant masses), frozen sections confirmed diagnosis of other 10 benign masses and reconfirmed diagnosis of the previously biopsied 20 malignant masses, the last 7 patients couldn't be biopsied & were diagnosed from patient medical profile at our institute. Conclusion: Addition of DWI &quantitative ADC mapping to routine MR examination is advised for evaluation of soft tissue tumors especially in the inconclusive cases. Keywords: Diffusion MRI, Soft tissue masses