New Method of Manganese-Enhanced Magnetic Resonance Imaging (MEMRI) for Rat Brain Research

• Published in: Experimental Animals Vol. 61; no. 2; pp. 157 - 164
• Main Authors: Jeong, Keun-Yeong, Lee, Chulhyun, Cho, Jee-Hyun, Kang, Ji-Hyuk, Na, Heung-Sik
• Format: Journal Article
• Language: English
• Published: Japan Japanese Association for Laboratory Animal Science 2012
• Subjects: Animals; Behavior, Animal - drug effects; Brain - metabolism; Brain Mapping - methods; cannula implantation; Chlorides - administration & dosage; Chlorides - toxicity; Contrast Media - administration & dosage; Contrast Media - toxicity; Dose-Response Relationship, Drug; Image Enhancement; Imaging, Three-Dimensional - methods; Infusions, Intraventricular; intracerebroventricular injection; Magnetic Resonance Imaging - methods; Male; Manganese Compounds - administration & dosage; manganese-enhanced MRI; Mn2; rat brain; Rats; Rats, Sprague-Dawley; Time Factors
• ISSN: 1341-1357; 1881-7122
• DOI: 10.1538/expanim.61.157

Manganese (Mn2+)-enhanced MRI (MEMRI) is known to provide insight into functional and anatomical biology. However, this method, which uses Mn2+ as a MRI-detectable contrast agent, has drawbacks such as the toxicity to cells beyond a certain level of Mn2+. In this study, we attempt to determine a new method of ICV administration, the optimal concentration of administered Mn2+ and the optimal MEMRI acquisition time following administration. Male Sprague-Dawley rats were used in the following experimental sessions: (1) intracerebroventricular (ICV) cannula implantation in the region of the cisterna magna, (2) serial dilution of MnCl2 (20–80 mM), (3) ICV administration of MnCl2 through the cannula, and (4) T1-weighted MRI measurements. We confirmed that cannula implantation in the region of the cisterna magna was a new ICV injection method for the administration of a contrast agent. The optimal concentration for MEMRI was 20/50 mM/μl of MnCl2. The MEMRI data acquired at different time points indicate that most signal enhancement is maintained during 14–48 h after contrast agent injection, and 24 h was the optimal time to acquire images of the rat brain. The present study offers optimized parameters for contrast agent injection that would be a good basis for studies using MEMRI to research the rat brain.