Increased signal intensity in the dentate nucleus on unenhanced T1-weighted MR images after multiple gadolinium-based contrast material administrations: a preliminary study

Abstract

Objective To compare changes in signal intensity (SI) of the dentate nucleus (DN), pons and cerebrospinal fluid (CSF) on unenhanced T1-weighted magnetic resonance imaging (MRI) scans after multiple administrations of the linear gadolinium-based contrast agent. Methods Clinical and imaging data of forty-nine patients who underwent at least 4 consecutive enhanced MRI examinations were analyzed retrospectively (unenhanced T1-weighted MRI scans were performed before and after consecutive enhanced MRI examinations). The mean SI of DN, pons and CSF were measured on unenhanced T1-weighted images. The SI ratio of DN to pons was calculated by dividing the SI in the DN by that in the pons, and so was The DN to CSF SI ratio. The difference of SI ratio of DN-to-pons and DN-to-CSF in the same patient before and after repeated contrast-enhanced T1WI were analyzed by paired-samples t tests. Linear regression analysis was used to analyze whether the SI ratios of DN-to-pons, DN-to-CSF were correlated with any clinical factor. Results The SI ratios of DN-to-pons and DN-to-CSF after multiple contrast administrations were higher than those before enhancement, and the differences were statistically significant. The SI ratios of DN-to-pons and DN-to-CSF before and after repeated contrast enhancement were 0.98±0.62, 1.05±0.54; 3.89±0.94, 4.97±1.61 (t=-8.494, -4.526, P 0.05). Conclusions This study indicates that serial injections of linear gadolinium-based contrast agent may lead to an increase in SI in the DN. Key words: Gadolinium; Dentate nucleus; Magnetic resonance imaging