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±0.28×10(−)(3) mm(2)/sec) compared to perilesional components (0.88±0.28×10(−)(3) mm(2)/sec) and background liver parenchyma (0.97±0.27×10(−)(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±10.85×10(−)(3) mm(2)/sec) than in background liver parenchyma (30.06±15.68×10(−)(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.