Manganese-Enhanced Magnetic Resonance Imaging: Application in Central Nervous System Diseases

Abstract

Manganese-enhanced magnetic resonance imaging (MEMRI) relies on the strong paramagnetism of Mn²⁺. Mn²⁺ is a calcium ion analog and can enter excitable cells through voltage-gated calcium channels. Mn²⁺ can be transported along the axons of neurons via microtubule-based fast axonal transport. Based on these properties, MEMRI is used to describe neuroanatomical structures, monitor neural activity, and evaluate axonal transport rates. The application of MEMRI in preclinical animal models of central nervous system (CNS) diseases can provide more information for the study of disease mechanisms. In this article, we provide a brief review of MEMRI use in CNS diseases ranging from neurodegenerative diseases to brain injury and spinal cord injury.

Keywords: MEMRI; brain injury; central nervous system; manganese; neurodegeneration.

Figure 1

(A) is the brain of a tree shrew in MEMRI after MnCl₂ intraperitoneal administration 24 h. The hippocampus can be observed enhancement. (B–D) are the visual pathways of a tree shrew in MEMRI. MEMRI can be used to observe visual pathways from the retina, optic nerve, optic chiasm, lateral geniculate nucleus, and superior colliculus after intravitreal injection of MnCl₂ in a tree shrew (a kind of squirrel-like mammal which is the closest to primates). H, hippocampus; R, retina; L, lens; ON, optic nerve; OC, optic chiasm; LGN, lateral geniculate nucleus; SC, superior colliculus.

Figure 2

MEMRI of a rat using left nasal administration of MnCl₂. Mn²⁺ uptake into the olfactory bulb (white arrows) and transport to olfactory cortex along the olfactory pathway. The red arrows indicate the lateral olfactory tract with unilateral enhancement. From (A–I) are axial continuous images of rat brain MRI.