[Influence of Inversion Time of Fat Suppression Methods on Measurement of Apparent Diffusion Coefficient]

Recently, tumor differentiation in various tissues has been performed by using the apparent diffusion coefficient (ADC) value. However, the influence of ADC value due to the different inversion time (TI) of fat suppression methods has not been reported yet. Therefore, the purpose of our study was to verify the influence of the different TI of fat suppression methods on the ADC value. ADC values were compared for diffusion-weighted imaging (DWI), using the short-TI inversion recovery (STIR) method and the spectral attenuated inversion recovery (SPAIR) method. For the STIR method, when TI was closed to the null point of each phantom, signal intensity decreased, and the ADC value thereby decreased. However, by the SPAIR method, signal intensity and ADC value were not affected by the inversion time. When using the STIR method, signal intensity decreased when the null point for each phantom was approached, which was thought to decrease the ADC value. In conclusion, when using STIR-DWI after contrast agent administration, the ADC value might have been affected by the TI.