Apparent diffusion coefficient and diffusion-weighted signal intensity of the interpeduncle region of the midbrain in adults: initial evaluation

ObjectiveThe diffusion-weighted signal intensity (SI) of the interpeduncle region (IPR) of the midbrain has not been fully understood. This study was to evaluate the apparent diffusion coefficient (ADC) and SI of the IPR on axial diffusion-weighted imaging (DWI).MethodsAxial brain DWI (4-mm slice thickness, no gap) was performed in 145 healthy subjects at 1.5T MR scanner. Correlations between the contrast-to-noise ratio (CNR) and ADC value in the IPR and age, gender were statistically analyzed.ResultsThe CNR was significantly higher in the IPR than in the periaqueductal gray (PAG) (P<.001). The CNR of the IPR positively correlated with age (P=.032) but not with gender (P=.091). The ADC value was significantly lower in the IPR than in the PAG (P<.001). The ADC value of the IPR did not correlate with age (P=.522) or gender (P=.217). There was no correlation between the CNR and ADC value of the IPR (P=.622).ConclusionsThe IPR usually shows high SI on DWI in healthy subjects, especially in older adults. DWI combined with the ADC maps would help to evaluate signal characteristics of the IPR.