Quantitative analyses of the correlation between dynamic contrast-enhanced MRI and intravoxel incoherent motion DWI in thyroid nodules.

This study investigated the correlation between dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and intravoxel incoherent motion diffusion-weighted imaging (IVIM DWI) to differentiate thyroid nodules. Quantitative DCE-MRI parameters, including the transfer constant (Ktrans), rate constant (Kep) and volume fraction of the extracellular extravascular space (Ve), were calculated. The diffusion coefficient (D), pseudo-diffusion coefficient (D* ), and perfusion fraction (f) were derived from biexponential fitting of IVIM DWI. A total of 38 nodules, including 22 malignant and 16 benign nodules, were analyzed. The Ktrans, Kep and Ve for benign lesions were 1.32 ± 0.76 min-1, 6.44 ± 1.44 min-1, and 2.02 ± 0.89 min-1, respectively, and for malignant lesions, the values were 0.84 ± 0.30 min-1, 5.43 ± 1.38 min-1, and 1.71 ± 0.83 min-1, respectively (P = 0.027, 0.036, and 0.257, respectively). The D, f, and D* for benign lesions were 1.51 ± 0.52 mm2/s, 26.63 ± 8.75%, and 15.84 ± 8.71 mm2/s, respectively, and for malignant lesions, the values were 0.68 ± 0.17 mm2/s, 31.63 ± 10.72%, and 11.10 ± 4.21 mm2/s, respectively (P [ 0.05). In benign nodules, a moderate inverse correlation was found between D and Kep (r = -0.54, P = 0.031). IVIM DWI shows no significant correlation with perfusion parameters derived from DCE-MRI; however, IVIM DWI combined with quantitative DCE-MRI may be a useful imaging tool for the assessment of thyroid nodules in clinical studies.