Program Information
Rapid High Magnetic Field MRI Scanning of Mouse Neuroanatomy and Labelled Cell Tracking
H Morris*, National Institutes of Health, Bethesda, MD
Presentations
MO-F-CAMPUS-IT-5 (Monday, July 31, 2017) 4:30 PM - 5:30 PM Room: Imaging ePoster Theater
Purpose: Develop and test MRI sequences of high image quality for relaying anatomical detail and detecting nanoparticle labelled neuroprogenitor stem cells. A focus of reduced scanning time is a determinate to use the method as a rapid screening tool.
Methods: MR images were acquired on a Bruker Avance III 14.1T NMR spectrometer with microimaging apparatus (Bruker Biospin, Inc., Billerica MA, USA) using a standard Avance RF III console, Micro-5 gradients (G=1.5 T/m, SR=2500 T/m/s) and 25 mm ID SAW RF coil. A modified Balanced Steady-State Free-Precession (SSFP) sequence was developed capable of phase-shifting within sequence lines. The 3D SSFP imaging parameters are TR/TE=2.0/1.0ms, pulse angle 60°, 1 NEX, FOV 30x18x13 mm, 512x340x168 for a resolution of 50x50x75 micron, with a total acquisition time of 1 minute 45 seconds per image. The linear combination SSFP (LCSSFP) images are the sum of 3 phase precession sequences. The time for each LCSSFP sequence is 5:15 resulting in a 3D image of 50 micron acquired resolution. Neuroprogenitor cells were labelled in situ via stereotactically injected FeO nanoparticles.
Results: The phase-progression of the RF pulse and receiver phase cancel the mis-registration artefact due to the large concentration of the label particles in the ventricles. The artefact cancellation does not affect the local field signature of the isolated FeO nanoparticles. The speed of the LCSSFP technique is most apparent when compared to the standard gradient recalled echo (GRE) sequence with a TR/TE=100 ms/5 ms for a total time of 53:42.
Conclusion: High-resolution images of rat brain injected with iron oxide particles can be acquired with a more than 10 fold increase in acquisition speed compared to standard GRE MRI sequences. The rapid production of data allows this technique to be used as a rapid screening tool with MRI that can compare with other imaging modalities
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