Comparison of T2 and T2 *-weighted MR molecular imaging of a mouse model of glioma
1 Department of Clinical Neurosciences and Radiology, University of Calgary, 3330 Hospital Dr NW, Calgary, Alberta T2N 4N1, Canada
2 Polish Academy of Sciences, Institute of Nuclear Physics, Krakow,152 Radzikowskiego, Krakow, Malopolska 31-342, Poland
3 Thunder Bay Regional Research Institute, 980 Oliver Road, Thunder Bay, Ontario P7B 6V4, Canada
4 Departments of Radiation Medicine, Radiology, Pediatrics, Loma Linda University Chan Shun Pavilion, Room A101011175 Campus Street, Loma Linda, California 92354, USA
5 Faculty of Veterinary Medicine, University of Calgary, 3330 Hospital Dr NW, Calgary, Alberta T2N 4N1, Canada
6 Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, Ontario K1H 8M5, Canada
7 Human Health Therapeutics Portfolio, National Research Council of Canada, Ottawa K1A 0R6, Ontario Canada
8 Alberta Innovates – Technology Futures, 3608 33 Street NW, Calgary T2L 2A6, Alberta, Canada
BMC Medical Imaging 2013, 13:20 doi:10.1186/1471-2342-13-20Published: 18 July 2013
Standard MRI has been used for high-grade gliomas detection, albeit with limited success as it does not provide sufficient specificity and sensitivity to detect complex tumor structure. Therefore targeted contrast agents based on iron oxide, that shorten mostly T2 relaxation time, have been recently applied. However pulse sequences for molecular imaging in animal models of gliomas have not been yet fully studied. The aim of this study was therefore to compare contrast-to-noise ratio (CNR) and explain its origin using spin-echo (SE), gradient echo (GE), GE with flow compensation (GEFC) as well as susceptibility weighted imaging (SWI) in T2 and T2* contrast-enhanced molecular MRI of glioma.
A mouse model was used. U87MGdEGFRvIII cells (U87MG), derived from a human tumor, were injected intracerebrally. A 9.4 T MRI system was used and MR imaging was performed on the 10 day after the inoculation of the tumor. The CNR was measured prior, 20 min, 2 hrs and 24 hrs post intravenous tail administration of glioma targeted paramagnetic nanoparticles (NPs) using SE, SWI, GE and GEFC pulse sequences.
The results showed significant differences in CNR among all pulse sequences prior injection. GEFC provided higher CNR post contrast agent injection when compared to GE and SE. Post injection CNR was the highest with SWI and significantly different from any other pulse sequence.
Molecular MR imaging using targeted contrast agents can enhance the detection of glioma cells at 9.4 T if the optimal pulse sequence is used. Hence, the use of flow compensated pulse sequences, beside SWI, should to be considered in the molecular imaging studies.