Contrast Agent–Induced High Signal Intensity in Dentate Nucleus on Unenhanced T1-Weighted Images: Comparison of Gadodiamide and Gadoxetic Acid
The aim of this study was to evaluate whether an association exists between T1-signal increase in the dentate nucleus (DN) on unenhanced magnetic resonance imaging and previous administration of gadoxetic acid and gadodiamide.Materials and Methods
This retrospective study was approved by the institutional review board; the requirement for informed patient consent was waived. A total of 132 patients (male-female ratio, 86:46; mean age, 68.8 ± 11.6 years) who underwent imaging between December 2000 and April 2016 were divided into 4 groups: patients with 5 or more administrations of gadoxetic acid (“gadoxetic acid ≥5 administrations” group), only 1 administration of gadoxetic acid (“gadoxetic acid 1 administration” group), no gadolinium-based contrast agent (GBCA) administration or chronic liver disease (CLD; “no GBCA administration and no CLD” group), and 5 or more administrations of gadodiamide (“gadodiamide ≥5 administrations” group). Unenhanced T1-weighted images were quantitatively analyzed by 2 radiologists. Intergroup comparison of DN-to-pons signal intensity ratios was performed by the Dunn test, with the no GBCA administration and no CLD group as control. Interobserver agreement was assessed by intraclass correlation coefficients.Results
The DN-to-pons ratio of the “gadodiamide ≥5 administrations” group was significantly higher (P < 0.0001) and those of the “gadoxetic acid ≥5 administrations” and “gadoxetic acid 1 administration” groups did not differ significantly (P = 0.3912 and 1.0000, respectively) compared with the DN-to-pons ratio of the “no GBCA administration and no CLD” group. The interobserver intraclass correlation coefficient for measurement of DN-to-pons ratio was excellent (0.835; 95% confidence interval, 0.767–0.883).Conclusions
Hyperintensity in the DN on unenhanced T1-weighted images is associated with previous administration of gadodiamide but not gadoxetic acid. Although the number of administrations for the 2 GBCA groups was identical, the administered dose of gadoxetic acid was only a quarter the amount of gadolinium as those with gadodiamide. This difference might influence the results of this study.