title: High Signal Intensity in Globus Pallidus and Dentate Nucleus on Unenhanced T1-weighted MR Images: Evaluation of Two Linear Gadolinium-based Contrast Agents.
abstract: OBJECTIVE
  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 patients who received gadodiamide (Omniscan), a linear nonionic gadolinium-based contrast agent, and in those who received gadobenate dimeglumine (MultiHance), a linear ionic contrast agent.
  
  
  METHODS
  Institutional review board approval was obtained for this single-center retrospective study, with waiver of informed consent. The study population included 69 patients divided into two groups: Group 1 included patients who underwent gadodiamide-enhanced MR imaging, and group 2 included patients who underwent gadobenate dimeglumine-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 patient 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 patients (19 female), with a mean of 5.0 doses ± 2.4 (standard deviation) (range, 3-11 doses) administered. Group 2 included 46 patients (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 patients had normal liver and renal function. Gadodiamide 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.
  
  
  CONCLUSIONS
  A significant increase in GP:TH and DN:MCP is associated with multiple gadodiamide-enhanced studies but not with gadobenate dimeglumine-enhanced studies, likely reflecting differences in stability and elimination of both contrast agents. Rate-of-change data indirectly suggest gadolinium deposition in the DN with gadobenate dimeglumine use, although it is considerably less than that with gadodiamide use.
authors.affiliation: From the Department of Radiology, University of North Carolina at Chapel Hill, CB 7510, 2001 Old Clinic Bldg, Chapel Hill, NC 27599-7510 (J.R., M.C., M.A., R.H.N., M.R., R.C.S.); Department of Radiology. King Faisal Specialist Hospital & Research Center, Riyadh. Saudi Arabia (M.A.); and Siemens Healthcare, Cary, NC (B.M.D.).
authors.forename: Joana
authors.initials: J
authors.lastname: Ramalho
authors.affiliation: From the Department of Radiology, University of North Carolina at Chapel Hill, CB 7510, 2001 Old Clinic Bldg, Chapel Hill, NC 27599-7510 (J.R., M.C., M.A., R.H.N., M.R., R.C.S.); Department of Radiology. King Faisal Specialist Hospital & Research Center, Riyadh. Saudi Arabia (M.A.); and Siemens Healthcare, Cary, NC (B.M.D.).
authors.forename: Mauricio
authors.initials: M
authors.lastname: Castillo
authors.affiliation: From the Department of Radiology, University of North Carolina at Chapel Hill, CB 7510, 2001 Old Clinic Bldg, Chapel Hill, NC 27599-7510 (J.R., M.C., M.A., R.H.N., M.R., R.C.S.); Department of Radiology. King Faisal Specialist Hospital & Research Center, Riyadh. Saudi Arabia (M.A.); and Siemens Healthcare, Cary, NC (B.M.D.).
authors.forename: Mamdoh
authors.initials: M
authors.lastname: AlObaidy
authors.affiliation: From the Department of Radiology, University of North Carolina at Chapel Hill, CB 7510, 2001 Old Clinic Bldg, Chapel Hill, NC 27599-7510 (J.R., M.C., M.A., R.H.N., M.R., R.C.S.); Department of Radiology. King Faisal Specialist Hospital & Research Center, Riyadh. Saudi Arabia (M.A.); and Siemens Healthcare, Cary, NC (B.M.D.).
authors.forename: Renato H
authors.initials: RH
authors.lastname: Nunes
authors.affiliation: From the Department of Radiology, University of North Carolina at Chapel Hill, CB 7510, 2001 Old Clinic Bldg, Chapel Hill, NC 27599-7510 (J.R., M.C., M.A., R.H.N., M.R., R.C.S.); Department of Radiology. King Faisal Specialist Hospital & Research Center, Riyadh. Saudi Arabia (M.A.); and Siemens Healthcare, Cary, NC (B.M.D.).
authors.forename: Miguel
authors.initials: M
authors.lastname: Ramalho
authors.affiliation: From the Department of Radiology, University of North Carolina at Chapel Hill, CB 7510, 2001 Old Clinic Bldg, Chapel Hill, NC 27599-7510 (J.R., M.C., M.A., R.H.N., M.R., R.C.S.); Department of Radiology. King Faisal Specialist Hospital & Research Center, Riyadh. Saudi Arabia (M.A.); and Siemens Healthcare, Cary, NC (B.M.D.).
authors.forename: Brian M
authors.initials: BM
authors.lastname: Dale
authors.affiliation: From the Department of Radiology, University of North Carolina at Chapel Hill, CB 7510, 2001 Old Clinic Bldg, Chapel Hill, NC 27599-7510 (J.R., M.C., M.A., R.H.N., M.R., R.C.S.); Department of Radiology. King Faisal Specialist Hospital & Research Center, Riyadh. Saudi Arabia (M.A.); and Siemens Healthcare, Cary, NC (B.M.D.).
authors.forename: Richard C
authors.initials: RC
authors.lastname: Semelka
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002529:Cerebellar Nuclei / Q000378:metabolism* / Q000473:pathology*; D003287:Contrast Media / Q000493:pharmacokinetics*; D005260:Female; D019786:Gadolinium DTPA / Q000493:pharmacokinetics*; D005917:Globus Pallidus / Q000378:metabolism* / Q000473:pathology*; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008536:Meglumine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D008875:Middle Aged; D009942:Organometallic Compounds / Q000493:pharmacokinetics*; D012189:Retrospective Studies; D013788:Thalamus / Q000378:metabolism* / Q000473:pathology*; D014018:Tissue Distribution; D055815:Young Adult
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C064572:gadobenic acid; D008536:Meglumine; C064925:gadodiamide; D019786:Gadolinium DTPA