In Vivo MRI

Cell Tracking may be performed in vivo provided the label is sensitive to the technique used for imaging. Fe particles in stem cells may be tracked using ultrashort echo time experiments which allow the very short T2 to be seen.

Compatible Scanners

• 500 MHz 89 mm NMR & MRI/S system (Tallahassee)
• 750 MHz 89 mm NMR Magnet (Gainesville)
• 11.1 Tesla 33 cm MRI/S System (Gainesville)

Compatible Probes

For 750 MHz 89 mm NMR & MRI/S System (Gainesville)

• 17.6 Tesla MRI probe for in-vivo imaging of rats with multiple head coils (NHMFL #52)

For 11.1 Tesla 40 cm MRI/S System (Gainesville)

• Agilent 395/290HD gradient bore size 290mm gmax = 100 mT/m, trise = 370 µs
• Agilent 205/120HD gradient – bore size 120mm, gmax = 600 mT/m, trise = 130 µs
• RRI 113/60 gradient bore size 60mm gmax = 1500 mT/m, trise = 130 µs

For 500 MHz 89mm NMR & MRI/S system (Tallahassee)

• 500 MHz Bruker Micro 2.5 probe for ex vivo and in vitro MRI adapted with multiple 1H and 7Li probe heads.
• 500 MHz NHMFL MRI probe for in vivo imaging of rats with 2-RF channels adapted with 1H probe head (NHMFL #35A)

This is an in vivo image of a mouse leg bone. The black dots are stem cells which have been tagged with iron particles which allows them to be easily tracked by standard imaging techniques.

For more information, please contact Sam Grant or Huadong Zeng.

This following instruments can be used with this technique:

• 500 MHz 89 mm NMR & MRI/S system (Tallahassee)
• 750 MHz 89 mm NMR Magnet (Gainesville)

This following probes can be used with this technique:

• 500 MHz Bruker Micro 2.5 probe for ex vivo and in vitro MRI adapted with multiple 1H and 7Li probe heads.
• 500 MHz NHMFL MRI probe for in vivo imaging of rats with 2-RF channels adapted with 1H probe head (NHMFL #35A)

For more information, please contact Tom Mareci in Gainesville or Sam Grant in Tallahassee.

Functional magnetic resonance imaging, or fMRI, makes it possible for us to non-invasively measure signatures of localized brain activity in variety of animal species, including humans. Its relatively good spatial and temporal resolution has opened a window to the mind like no other technique in scientific history. The most popular functional imaging technique relies on the blood oxygen level dependent (BOLD) contrast mechanism first reported by Ogawa and colleagues in the late 80’s and early 90’s. A variant of T2 relaxation, known as T2* (“T-2-star”), is produced by inhomogeneities or imperfections in the main magnetic field generated by the MRI scanner. This inhomogenous environment causes reductions faster transverse relaxation that then becomes sensitive to the oxygenation state of the brain tissue. Deoxyhemoglobin in plasma red blood cells is paramagnetic while oxyhemoglobin is diamagnetic. The intravascular difference between the two provides for an endogenous contrast mechanism. Early in the 90’s Ogawa and co-workers provided evidence that a decreased T2* signal in blood vessels, particularly veins of the rat cortex, is due to blood oxygenation state. Darker veins in the cortex were distinguishable in rats inhaling low oxygen concentrations in inspired air while increased oxygen saturation (significantly less deoxyhemoglobin concentration in blood veins and venules) increased the brightness of the MR images. Thus, this T2* contrast mechanism was shown to be dependent on blood oxygenation. Publications providing support for task-dependent changes in the BOLD signal followed and the application of fMRI emerged in the many fields of neuroscience. The use of 4.7 T and 11.1 T horizontal bore systems for rodent and other small animal applications are optimal both because of the high signal-to-noise ratio and excellent T2* contrast for functional studies. An advantage of having higher resolution images obtained in higher field systems (11.1 T to 17.6 T, and above) is that they can create voxels that better localize activity in the brain without significant losses in signal to noise. Our laboratory employs fMRI techniques in a variety of applications to gain an understanding of how the brain works and following the progression of specific neuropsychiatric like and neurodegenerative diseases.

Compatible Scanners

• 750 MHz 89 mm NMR Magnet (Gainesville)
• 11.1 Tesla 33 cm MRI/S System (Gainesville)
• 3 Tesla 70 cm Scanner (Gainesville)

Compatible Probes

For 750 MHz 89 mm NMR & MRI/S System (Gainesville)

• Micro 2.5 Imaging probe with 5mm, 10mm, 15mm, 20mm, 25mm and 30mm coils
• Mini 0.75 Imaging probe with 33mm 1H coil

For 11.1 Tesla 40 cm MRI/S System (Gainesville)

• Agilent 395/290HD gradient bore size 290mm gmax = 100 mT/m, trise = 370 µs
• Agilent 205/120HD gradient – bore size 120mm, gmax = 600 mT/m, trise = 130 µs
• RRI 113/60 gradient bore size 60mm gmax = 1500 mT/m, trise = 130 µs

For more information, please contact Marcelo Febo.

Localized spectroscopy techniques such as STEAM, PRESS, ISIS and CSI may be used to provide spectra of 1H, 13C and 31P both in excised tissue and in vivo.

Compatible Scanners

• 500 MHz 89 mm NMR & MRI/S system (Tallahassee)
• 900 MHz 105 mm NMR Magnet (Tallahassee)
• 750 MHz 89 mm NMR Magnet (Gainesville)
• 11.1 Tesla 33 cm MRI/S System (Gainesville)

Compatible Probes

For 750 MHz 89 mm NMR & MRI/S System (Gainesville)

• 17.6 Tesla MRI probe for in-vivo imaging of rats with multiple head coils (NHMFL #52)

For 11.1 Tesla 40 cm MRI/S System (Gainesville)

• Agilent 395/290HD gradient bore size 290mm gmax = 100 mT/m, trise = 370 µs
• Agilent 205/120HD gradient – bore size 120mm, gmax = 600 mT/m, trise = 130 µs
• RRI 113/60 gradient bore size 60mm gmax = 1500 mT/m, trise = 130 µs

For 500 MHz 89mm NMR & MRI/S system (Tallahassee)

• 500 MHz Bruker Micro 2.5 probe for ex vivo and in vitro MRI adapted with multiple 1H and 7Li probe heads.
• 500 MHz NHMFL MRI probe for in vivo imaging of rats with 2-RF channels adapted with 1H probe head (NHMFL #35A)

For more information, please contact Sam Grant (Tallahassee), Huadong Zeng (Gainesville) or Joanna Long (Gainesville).