High Signal Intensity in Globus Pallidus and Dentate Nucleus on Unenhanced T1-weighted MR Images: Evaluation of Two Linear XXXX -based Contrast Agents.

@entity1 @entity2287 @entity23432 @entity5777
UNASSIGNED: Purpose To determine if a correlation exists between the number of previous enhanced magnetic resonance (MR) imaging examinations and high signal intensity in the globus pallidus (GP) and dentate nucleus (DN) in @entity1 who received @entity5777 ( @entity5777 ), a linear nonionic @entity2287 -based contrast agent, and in those who received @entity23432 (MultiHance), a linear ionic contrast agent. Materials and Methods Institutional review board approval was obtained for this single-center retrospective study, with waiver of informed consent. The study population included 69 @entity1 divided into two groups: Group 1 included @entity1 who underwent @entity5777 -enhanced MR imaging, and group 2 included @entity1 who underwent @entity23432 -enhanced MR imaging. Two radiologists conducted a quantitative analysis of unenhanced T1-weighted images by using region of interest measurements. The GP-to-thalamus (TH) signal intensity ratio, DN-to-middle cerebellar peduncle (MCP) signal intensity ratio and relative percentage change (Rchange) between the first and last examinations for each @entity1 were calculated. Relation between the signal intensity ratios and Rchange and the number of enhanced MR imaging examinations was analyzed by using a generalized additive model. Inter- and intraobserver agreement was evaluated with the Lin concordance correlation coefficient test. Results Group 1 included 23 @entity1 (19 female), with a mean of 5.0 doses    2.4 (standard deviation) (range, 3-11 doses) administered. Group 2 included 46 @entity1 (24 female) with a mean of 4.6 doses    2.2 (range, 3-11 doses) administered. The interval between the first and last examination was 1500.1 days    780.2 (range, 98-3097 days) for group 1 and 1086.2 days    582.9 (range, 94-2633) for group 2. All @entity1 had normal liver and renal function. @entity5777 showed a significant increase in DN:MCP and GP:TH (P < .001 for both) and in Rchange (P = .001 for GP:TH, P < .001 for DN:MCP). In group 2, there was no significant increase in DN:MCP or GP:TH over time or in Rchange for GP:TH, but there was a significant trend toward an increase in Rchange for DN:MCP (P = .013). Interobserver agreement was almost perfect (0.99; 95% confidence interval: 0.99, 0.99) for all evaluated structures. Intraobserver agreement was substantial to almost perfect for both readers. Conclusion A significant increase in GP:TH and DN:MCP is associated with multiple @entity5777 -enhanced studies but not with @entity23432 -enhanced studies, likely reflecting differences in stability and elimination of both contrast agents. Rate-of-change data indirectly suggest @entity2287 deposition in the DN with @entity23432 use, although it is considerably less than that with @entity5777 use. (  ) RSNA, 2015.
