Diffusion kurtosis imaging and dynamic contrast-enhanced MRI for the differentiation of parotid gland tumors.

ABSTRACT

OBJECTIVE: To assess the usefulness of combined diffusion kurtosis imaging (DKI) and dynamic contrast-enhanced MRI (DCE-MRI) in the differentiation of parotid gland tumors. METHODS: Seventy patients with 80 parotid gland tumors who underwent DKI and DCE-MRI were retrospectively enrolled and divided into four groups pleomorphic adenomas (PAs), Warthin tumors (WTs), other benign tumors (OBTs), and malignant tumors (MTs). DCE-MRI and DKI quantitative parameters were measured. The Kruskal-Wallis H test and post hoc test with Bonferroni correction and ROC curve were used for statistical analysis. RESULTS: WTs demonstrated the highest Kep value (median 1.89, interquartile range [1.46-2.31] min-1) but lowest Ve value (0.20, [0.15-0.25]) compared with PAs (Kep, 0.34 [0.21-0.55] min-1; Ve, 0.36 [0.24-0.43]), OBTs (Kep, 1.22 [0.27-1.67] min-1; Ve, 0.28 [0.25-0.41]), and MTs (Kep, 0.71 [0.50-1.23] min-1; Ve, 0.35 [0.26-0.45]) (all p < .05). MTs had the lower D value (1.10, [0.88-1.29] × 10-3 mm2/s) compared with PAs (1.81, [1.60-2.20] × 10-3 mm2/s) and OBTs (1.57, [1.32-1.89] × 10-3 mm2/s) (both p < .05). PAs had the lower Ktrans value (0.12, [0.07-0.18] min-1) compared with OBTs (0.28, [0.11-0.50] min-1) (p < .05). The cutoff values of combined Kep and Ve, D, and Ktrans to distinguish WTs, MTs, and PAs sequentially were 1.06 min-1, 0.28, 1.46 × 10-3 mm2/s, and 0.21 min-1, respectively (accuracy, 89% [71/80], 91% [73/80], 78% [62/80], respectively). CONCLUSION: The combined use of DKI and DCE-MRI may help differentiate parotid gland tumors. KEY POINTS • The combined use of DKI and DCE-MRI could facilitate the understanding of the pathophysiological characteristics of parotid gland tumors. • A stepwise diagnostic diagram based on the combined use of DCE-MRI parameters and the diffusion coefficient is helpful for accurate preoperative diagnosis in parotid gland tumors and may further facilitate the clinical management of patients.