Increased anatomical detail by in vitro MR microscopy with a modified Golgi impregnation method

Abstract

Golgi impregnation is unique in its ability to display the dendritic trees and axons of large numbers of individual neurons by histology. Here we apply magnetic resonance microscopy to visualize the neuroanatomy of animal models by combining histologic fixation chemistry with paramagnetic contrast agents. Although there is some differential uptake of the standard small-molecular-weight contrast agents by different tissue types, detailed discrimination of tissue architecture in MR images does not approach that of standard histology. Our modified Golgi impregnation method significantly increases anatomic detail in magnetic resonance microscopy images. Fixed mouse brains were treated with a solution containing a paramagnetic contrast agent (gadoteridol) and potassium dichromate. Results demonstrate a specific contrast enhancement likely due to diamagnetic hexavalent chromium undergoing tissue specific reduction to paramagnetic trivalent chromium. This new method dramatically improves neuroanatomical contrast compared to conventional fixation, displaying detail approximating that of histologic specimens at low (43) magnification. Magn Reson Med 63:1391-1397,

Enhanced characterization of the zebrafish brain as revealed by super-resolution track-density imaging

“…As a result, researchers rely on a variety of pulse sequences to exploit variations in either proton density and tissue relaxation properties (Johnson et al 2010;McLaren et al 2009;Johnson et al 2012), and/or a limited number of contrast agents. To date the majority of studies have utilized gadolinium-based contrast agents, such as Magnevist® and Pro-Hance®, however Manganese, a functional contrast agent (Koretsky and Silva 2004) (Leergaard et al 2003), and more recently potassium dichromate (Rowland 2011;Zhang et al 2010) and myelin-specific (Frullano et al 2012) contrast agents have also been used.…”

3D high spectral and spatial resolution imaging of ex vivo mouse brain

“…The structures visible in these water peak height images are consistent with anatomy previously demonstrated by MR imaging using an exogenous contrast agent introduced during the fixative process. [48][49][50][51][52] Of interest, the pyramidal layer appears multilaminar, [53][54][55][56] a feature that correlates with acetylcholinesterase staining [ Fig. 3(c)].…”

Long-Term Effects of Neonatal Hypoxia-Ischemia on Structural and Physiological Integrity of the Eye and Visual Pathway by Multimodal MRI

“…20,[41][42][43] In the eye, lipid peroxidation may play an important role in degenerative diseases, such as AMD, cataract, glaucoma, retinopathy of prematurity, and diabetic retinopathy. 44 Chromium-enhanced MRI may provide an in vivo biomarker to help determine the pathophysiological and pharmacological implications of lipid peroxidation in the injured eye, as peroxides and metabolites of long-chain polyunsaturated fatty acids in the retina may alter the integrity of neurotransmitter pools and provide new potential target sites and pathways for the treatment of degenerative ocular diseases.…”