Differentiation between malignant and benign musculoskeletal tumors using diffusion kurtosis imaging

ObjectiveThe purpose of this study was to evaluate differences in parameters of diffusion kurtosis imaging (DKI) and minimum apparent diffusion coefficient (ADC(min)) between benign and malignant musculoskeletal tumors.Materials and methodsIn this prospective study, 43 patients were scanned using a DKI protocol on a 3-T MR scanner. Eligibility criteria were: non-fatty, non-cystic soft tissue or osteolytic tumors; >2cm; location in the retroperitoneum, pelvis, leg, or neck; and no prior treatment. They were clinically or histologically diagnosed as benign (n=27) or malignant (n=16). In the DKI protocol, diffusion-weighted imaging was performed using four b values (0-2000s/mm(2)) and 21 diffusion directions. Mean kurtosis (MK) values were calculated on the MR console. A recently developed software application enabling reliable calculation was used for DKI analysis.ResultsMK showed a strong correction with ADC(min) (Spearman's rs=0.95). Both MK and ADC(min) values differed between benign and malignant tumors (p<0.01). For benign and malignant tumors, the mean MK values (SD) were 0.49 +/- 0.17 and 1.14 +/- 0.30, respectively, and ADC(min) values were 1.54 +/- 0.47 and 0.49 +/- 0.17x10(-3)mm(2)/s, respectively. At cutoffs of MK=0.81 and ADC(min)=0.77x10(-3)mm(2)/s, the specificity and sensitivity for diagnosis of malignant tumors were 96.3 and 93.8% for MK and 96.3 and 93.8% for ADC(min), respectively. The areas under the curve were 0.97 and 0.99 for MK and ADC(min), respectively (p=0.31).Conclusions p id=Par4 MK and ADC(min) showed high diagnostic accuracy and strong correlation, reflecting the accuracy of MK. However, no clear added value of DKI could be demonstrated in differentiating musculoskeletal tumors.