Mouse brain fixation to preserve In vivo manganese enhancement for ex vivo manganese-enhanced MRI.
OBJECTIVE
To develop a tissue fixation method that preserves in vivo manganese enhancement for ex vivo magnetic resonance imaging (MRI). The needs are clear, as conventional in vivo manganese-enhanced MRI (MEMRI) applied to live animals is time-limited, hence limited in spatial resolution and signal-to-noise ratio (SNR). Ex vivo applications can achieve superior spatial resolution and SNR through increased signal averaging and optimized radiofrequency coil designs. A tissue fixation method that preserves in vivo Mn(2+) enhancement postmortem is necessary for ex vivo MEMRI.


METHODS
T1 measurements and T1 -weighted MRI were performed on MnCl2 -administered mice. The mice were then euthanized and the brains were fixed using one of two brain tissue fixation methods: aldehyde solution or focused beam microwave irradiation (FBMI). MRI was then performed on the fixed brains.


RESULTS
T1 values and T1 -weighted signal contrasts were comparable between in vivo and ex vivo scans on aldehyde-fixed brains. FBMI resulted in the loss of Mn(2+) enhancement.


CONCLUSIONS
Aldehyde fixation, not FBMI, maintained in vivo manganese enhancement for ex vivo MEMRI.
Department of Radiology, University of Nebraska Medical Center, Omaha, NE 68198, USA. yutongliu@unmc.edu
Yutong
Y
Liu
Balasrinivasa R
BR
Sajja
Howard E
HE
Gendelman
Michael D
MD
Boska
D000447:Aldehydes; D000818:Animals; D001921:Brain / Q000033:anatomy & histology* / Q000528:radiation effects; D001923:Brain Chemistry / Q000528:radiation effects*; D002712:Chlorides / Q000737:chemistry; D003287:Contrast Media / Q000737:chemistry; D005404:Fixatives; D007089:Image Enhancement / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D017895:Manganese Compounds / Q000737:chemistry; D051379:Mice; D016513:Mice, SCID; D008872:Microwaves; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016707:Tissue Fixation / Q000379:methods*
D000447:Aldehydes; D002712:Chlorides; D003287:Contrast Media; D005404:Fixatives; D017895:Manganese Compounds; C025340:manganese chloride
MRI; aldehyde; ex vivo MRI; focused beam microwave irradiation; manganese enhanced MRI; tissue fixation