Volume 56, Issue 5 pp. 1499-1504
Research Article

Optimization of Detection of Gadodiamide Brain Retention in Rats Using Quantitative T2 Mapping and Intraperitoneal Administration

Serguei M. Liachenko MD, PhD

Corresponding Author

Serguei M. Liachenko MD, PhD

Division of Neurotoxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, USA

Address reprint requests to: S.L., 3900 NCTR Rd, Jefferson, AR 72079, USA. E-mail: [email protected]

Search for more papers by this author
Natalya V. Sadovova PhD

Natalya V. Sadovova PhD

Division of Neurotoxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, USA

Search for more papers by this author
Arnold Tripp

Arnold Tripp

Division of Neurotoxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, USA

Search for more papers by this author
Suman Ghorai PhD

Suman Ghorai PhD

Nanotechnology Core Facility, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, USA

Search for more papers by this author
Anil K. Patri PhD

Anil K. Patri PhD

Nanotechnology Core Facility, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, USA

Search for more papers by this author
Joseph P. Hanig PhD

Joseph P. Hanig PhD

Office of Pharmaceutical Quality, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, White Oak, Maryland, USA

Search for more papers by this author
Jonathan E. Cohen PhD

Jonathan E. Cohen PhD

Office of New Drugs, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, White Oak, Maryland, USA

Search for more papers by this author
Ira Krefting MD

Ira Krefting MD

Office of New Drugs, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, White Oak, Maryland, USA

Search for more papers by this author
First published: 12 March 2022

This article reflects the views of the authors and should not be construed to represent US FDA's views or policies.

Abstract

Background

Currently, the gadolinium retention in the brain after the use of contrast agents is studied by T1-weighted magnetic resonance imaging (MRI) (T1w) and T1 mapping. The former does not provide easily quantifiable data and the latter requires prolonged scanning and is sensitive to motion. T2 mapping may provide an alternative approach. Animal studies of gadolinium retention are complicated by repeated intravenous (IV) dosing, whereas intraperitoneal (IP) injections might be sufficient.

Hypothesis

T2 mapping will detect the changes in the rat brain due to gadolinium retention, and IP administration is equivalent to IV for long-term studies.

Study Type

Prospective longitudinal.

Animal Model

A total of 31 Sprague–Dawley rats administered gadodiamide IV (N = 8) or IP (N = 8), or saline IV (N = 6) or IP (N = 9) 4 days per week for 5 weeks.

Field strength/sequences

A 7 T, T1w, and T2 mapping.

Assessment

T2 relaxation and image intensities in the deep cerebellar nuclei were measured pre-treatment and weekly for 5 weeks. Then brains were assessed for neuropathology (N = 4) or gadolinium content using inductively coupled plasma mass spectrometry (ICP-MS, N = 12).

Statistical tests

Repeated measures analysis of variance with post hoc Student–Newman–Keuls tests and Hedges' effect size.

Results

Gadolinium was detected by both approaches; however, T2 mapping was more sensitive (effect size 2.32 for T2 vs. 0.95 for T1w), and earlier detection (week 3 for T2 vs. week 4 for T1w). ICP-MS confirmed the presence of gadolinium (3.076 ± 0.909 nmol/g in the IV group and 3.948 ± 0.806 nmol/g in the IP group). There was no significant difference between IP and IV groups (ICP-MS, P = 0.109; MRI, P = 0.696). No histopathological abnormalities were detected in any studied animal.

Conclusion

T2 relaxometry detects gadolinium retention in the rat brain after multiple doses of gadodiamide irrespective of the route of administration.

Evidence Level

1

Technical Efficacy

Stage 1

The full text of this article hosted at iucr.org is unavailable due to technical difficulties.