Quantitative differentiation of malignant and benign thyroid nodules with multi-parameter diffusion-weighted imaging

Table 2 Comparison of diffusion parameters between benign and malignant thyroid nodules

Diffusion parameter	Benign nodules	Malignant nodules	P value
Mono-exponential
ADC(0 and 1000)	1.85 ± 0.24	1.29 ± 0.27	< 0.01
ADC(0 to 1000)	1.79 ± 0.021	1.19 ± 0.23	< 0.01
ADC(0 and 2000)	1.35 ± 0.15	0.95 ± 0.15	< 0.01
ADC(0 to 2000)	1.41 ± 0.15	0.95 ± 0.15	< 0.01
Biexponential
D	1.34 ± 0.41	0.89 ± 0.26	< 0.01
D*	22.08 ± 18.53	26.09 ± 20.87	> 0.05
f	0.38 ± 0.19	0.30 ± 0.14	< 0.01
Stretched exponential
DDC	2.15 ± 0.62	1.45 ± 0.51	< 0.01
α	0.78 ± 0.19	0.67 ± 0.19	< 0.01
Kurtosis DWI
Dapp	2.88 ± 0.73	2.11 ± 0.67	< 0.01
Kapp	0.57 ± 0.12	0.85 ± 0.19	< 0.01

ADC: Apparent diffusion coefficient; D: Slow diffusion coefficient; D*: Fast diffusion coefficient; f: Fraction of fast diffusion; DDC: Distributed diffusion coefficient; α: Anomalous exponent term; DWI: Diffusion-weighted imaging; Dapp: Mean diffusivity; Kapp, mean kurtosis. The ADC, D, D*, DDC, and Dapp are given in units of ×10^-3 mm²/s. P values from statistical comparison between benign and malignant nodules were obtained by using the Mann–Whitney U test.