• Oxford 30-cm horizontal bore magnet
• GE 12.5 EXCITE console that provides reception at frequencies from 13-85 MHz
• A set of 40 Gauss/cm shielded gradients provide very rapid switching at 400 mT/m over a 120-mm clear bore
• Interfaces to a scan-synchronous ventilator system
• 1 MHz receiver

Figure of a pre-Methocholine drug-induced challenge of an ovalbumin-sensitized mouse, imaged on the 2T MR with hyperpolarized 3He.

Adapted from NN Mistry, A Thomas, SS Kaushik, GA Johnson, B Driehuys, Quantitative analysis of hyperpolarized 3He ventilation changes in mice challenged with Methacholine, Magn Reson Med 63:658–666, 2010, Free PMC article

• Magnex 21-cm horizontal bore magnet
• GE 12.5X EXCITE console provides simultaneous excitation in 2 channels and reception in 8 channels at frequencies from 46-300 MHz
• A set of shielded gradients provide very rapid switching at 770 mT/m over a 90-mm clear bore
• Interfaces to a scan-synchronous ventilator system
• 1 MHz receiver

• Longitudinal diffusion tensor imaging (DTI) of blast-induced traumatic brain injury
• High-resolution vascular imaging of the mouse brain
• Kidney studies

The 7T Bruker magnet in the Warren lab in the Bryan Research Building is used for imaging and spectroscopy of proton, carbon, and nitrogen.

• Work focuses on the design and application of what might best be called novel pulsed techniques, using both linear and non-linear signals to improve cancer detection and image absolute temperature.
• Another focus is on extending the lifetime of carbon and nitrogen hyperpolarization.
• The heart of the work is chemical physics, and it generally involves an intimate mixture of theory and experiment.

Example of a 9.4 T diffusion tensor imaging color map from a mouse brain in axial view, averaged from the population of 8 mice in this study.

Figure adapted from Jiang and Johnson, Diffusion tensor atlas of the mouse brain, Neuroimage 56:1235-1243, 2011

• Oxford 8.9-cm vertical bore magnet
• GE 12.5X EXCITE console provides simultaneous reception in 2 channels from 60-400 MHz

MICRO-CT / MICRO X-RAY

• X-ray tubes and detectors are arranged orthogonally
• 2 Varian G297 x-ray tubes (fs=0.3/0.8 mm)
• 2 Epsilon High Frequency X-ray generators (EMD Technologies, Quebec, Canada)
• 2 XDI-VHR CCD x-ray detectors (Photonic Science, East Sussex, UK) with a Gd₂O₂S phosphor and 22-micron pixel size

This equipment is also used as a biplane digital subtraction angiography (DSA) system for small animal coronary angiography.

Adapted from: CT Badea, M Drangova, DW Holdsworth, GA Johnson, In vivo small-animal imaging using micro-CT and digital subtraction angiography, Phys. Med. Biol. 53(19): R319-R350, 2008, Free PMC article

U-SPECT-II/CT

• 75 pinholes, 3D focusing technology (ultra-high resolution: <0.35mm in entire mouse, <0.9 mm in entire rat; quantification of molecules in tiny parts of organs; low dose and high-resolution total body imaging)
• List-mode data acquisition (high number of energy channels (simultaneous multi-isotope imaging; retrospective gating and energy window selection; flexible dose and scan time planning)
• Stationary detectors for ultra-fast dynamic scanning

Image from a 4D cardiac SPECT study:

• C57Bl/6 male 25g mouse IV tail vein injection of Tc-99m Myoview
• 0.35mm high-resolution collimator
• Scan time: 2 hours

Cardiac SPECT movie

ULTRASOUND

• Visualsonics Vevo 770 Ultrasound system
• Operates at 40 MHz
• Spatial resolution down to 30 microns

The figure to the right shows how we adapt the ultrasound to open the blood-brain barrier (BBB) using unfocused ultrasound and microbubbles for a mouse brain study. The ultrasound and microbubble technique is noninvasive, transcranial, and reversible, and by using an unfocused transducer, this opens the BBB in both hemispheres in a single insonification. This technique uses commercially available components, takes only a few minutes, and requires no expertise in ultrasound.

This figure adapted from Howles et al. 2010, shows results from the technique that we call BOMUS (BBB Opening with Microbubbles and UltraSound). The MR-7T system was used with Gd- DTPA contrast enhancement.

See our publication about this technique: GP Howles, KF Bing, Y Qi, SJ Rosenzweig, KR Nightingale, GA Johnson, Contrast-enhanced in vivo magnetic resonance microscopy of the mouse brain enabled by non-invasive opening of the blood-brain barrier with ultrasound, Magn Reson Med, 64(4):995-1004. 2010.

CONFOCAL MICROSCOPE

This confocal microscope from Carl Zeiss AG is another recent addition to our lab.

Confocal microscopy will offer these benefits for our various studies, including controllable depth of field, the elimination of image degrading out-of-focus information, and the ability to collect serial optical sections from thick specimens. (Definition extracted from this source.)

COMPUTERS / NETWORK / VISUALIZATION TOOLS

The computer environment, image archiving, and distribution are particular strengths of the Center, with resources including:

• A fully supported network of more than 120 Sun, Silicon Graphics (SGI), Macintosh, LINUX, and PC workstations, linked on a switched 100 GB/sec network designed for very large image arrays (currently up to 40 GB/array).
• 5 dedicated image reconstruction engines, each with TB RAID disks, developed for MR image reconstruction and analysis.
• Automated archiving of all images generated at the Center.
• Data is available via a secure web tool that allows our collaborators or image reviewers to search, retrieve, and analyze their data interactively (from our database) anywhere with a high-speed connection to the web.

• A wide range of Macintosh and PCs, and several dedicated high-end visualization computers equipped with visualization and image registration software packages (including Vitrea, Amira, and VGStudio MAX).
• To facilitate remote collaborations, a Polycom unit interfaced with a 55-inch 1080p network-compatible Sony flat-screen is available for teleconferencing.
• The Center’s computing infrastructure is supervised by a dedicated network administrator and a staff member, who also work on reconstruction and visualization.