Comparison of Intravoxel Incoherent Motion Diffusion-Weighted Magnetic Resonance (MR) Imaging to T1 Mapping in Characterization of Hepatic Alveolar Echinococcosis

Background: The aim of this study was to compare intravoxel incoherent motion diffusion-weighted magnetic resonance imaging (IVIM DW MRI) to T1 mapping for characterization of hepatic alveolar echinococcosis (HAE). Material/Methods: Eighteen HAE patients confirmed by surgery were examined with conventional MRI, IVIM DWI MRI with 10 b values (range: 0-1,000 sec/mm(2)), and longitudinal relaxation time (T1) mapping. Diffusion coefficient (D), perfusion fraction (f), pseudo-diffusion coefficient (D*), and T1 relaxation time were calculated in solid components, perilesional components, and background liver parenchyma of HAE patients. The correlation between T1 relaxation time and IVIM-derived parameters was assessed by using the Pearson correlation test. Results: T1 relaxation times were significantly higher in solid components (820.58 +/- 331.24 ms) compared to background components (551.52 +/- 182.93 ms) of HAE patients (p<0.05). IVIM-derived D values were significantly higher in solid components (1.30 +/- 0.28x10(-3) mm(2)/sec) compared to perilesional components (0.88 +/- 0.28x10(-3) mm(2)/sec) and background liver parenchyma (0.97 +/- 0.27x10(-3) mm(2)/sec) of liver parenchyma. There were significant differences in f values between solid components (13.70 +/- 7.66%), perilesional components (23.59 +/- 10.73%) and background liver parenchyma (30.78 +/- 10.18%). IVIM derived D* values were significantly lower in solid components (14.32 +/- 10.85x10(-3) mm(2)/sec) than in background liver parenchyma (30.06 +/- 15.68x10(-3) mm(2)/sec). Importantly, IVIM-derived f values were significantly correlated with T1 relaxation time: r=-0.337 (p<0.05). Conclusions: Based on our image comparison, IVIM DWI MRI might be better than T1 mapping, and IVIM-derived f values might be a valuable index for characterization of HAE.