Intravoxel incoherent motion combined with conventional MRI for the differentiation of benign, intermediate, and malignant fibrous soft-tissue tumors.

BACKGROUND

Fibroblastic/myofibroblastic tumors are among the most common soft-tissue tumors (STTs) encountered clinically. Several magnetic resonance imaging (MRI) features associated with malignant tumors overlap with benign tumors, making differential diagnosis challenging. Intravoxel incoherent motion (IVIM) is a valuable MRI technique for differentiating various tumors. This study aims to evaluate the abilities of conventional MRI and IVIM in differentiating benign, intermediate, and malignant fibrous STTs.

METHODS

Fifty-five patients with fibrous STTs were prospectively enrolled, comprising 18 benign, 18 intermediate, and 19 malignant cases. All the patients underwent MRI examinations including IVIM. Conventional MRI signs and standard-apparent diffusion coefficient (ADC), true diffusion coefficient (D), pseudo-diffusion coefficient (D*), and perfusion fraction (f) were recorded. Statistical analyses were performed using Kruskal-Wallis H test, Chi-square test,post hoc test with Bonferroni correction, receiver operating characteristic (ROC) curves, and DeLong test. p < 0.05 indicated statistical significance.

RESULTS

Malignant tumors had higher heterogeneity on T2WI (p = 0.020 and 0.009) and contrast enhancement T1WI (p = 0.013 and 0.029), and were more prone to necrosis (p < 0.001 andp = 0.001) compared with benign and intermediate tumors, respectively. Tail-like pattern (p = 0.034 and 0.009) and invasiveness (p = 0.018 and 0.033) were more frequently observed in intermediate and malignant tumors than in benign tumors, respectively. Standard-ADCmean, standard-ADCmin, Dmean, and Dmin values decreased from benign to intermediate and malignant fibrous STTs. Malignant STTs displayed higher fmean and fmin values than benign tumors (p = 0.002 and 0.013, respectively). Standard-ADCmean showed the highest AUC (0.894) in differentiating intermediate from benign STTs. Dmean showed the highest AUC (0.961 and 0.905) in differentiating malignancies from benign and intermediate STTs, respectively. For discriminating between benign and non-benign fibrous STTs, the combination of conventional MRI signs and IVIM parameters yielded the highest AUC of 0.971.

CONCLUSION

IVIM diffusion parameters differentiated benign, intermediate, and malignant fibrous STTs and can complement conventional MRI signs.