Small Animal Imaging Modalities
Imaging modalities are used to noninvasively study disease pathophysiology in the brain. Different modalities for small animal imaging are used to assess gross anatomical structures, as well as changes in cellular and molecular structure and function. Advances in imaging techniques have allowed improved sensitivity and specificity for clinical and biomarker endpoints in animal models, consequently supporting early diagnosis and more efficient disease monitoring. MRI, PET, and SPECT are translational preclinical imaging methods that serve as a bridge between preclinical studies in small animals and clinical endpoints.
Small animal imaging has the potential to dramatically increase the efficiency of lead candidate selection by providing earlier and more highly predictive data, compared with traditional methods. Imaging is also well suited for facilitating translation between preclinical testing and clinical evaluation of drugs. Noninvasive testing methods such as imaging are more easily applied than traditional methods such as histology in more predictive models of disease. Small animal imaging can be easily combined with other testing modalities to provide a multi-modal set of endpoints.
Charles River’s preclinical neurological imaging capabilities include high-field MRI, PET/CT, and SPECT/CT scanners for radionuclide-based applications. These platforms are applicable for longitudinal studies with multiple imaging endpoints to study phenotype progression and treatment efficacy, as well as biodistribution or tissue activity changes. Currently, the imaging hardware for MRI studies on rodents include a 7.0T MRI scanner and 11.7T MRI scanner that are manned by 6 full time technicians and 2 scientists. MRI capabilities include phMRI (pharmacological MRI), vascular imaging and anatomical imaging). More recently, we have developed functional animal ultrasound capabilities that is used to sensitively image awake animals.
After a single administration, radiolabeled compounds can be used to follow pharmacokinetics and biodistribution profile for several days in the same animal with SPECT/CT. In addition to SPECT/CT, tissue gamma counter analysis can be added in all studies for a more complete biodistribution profile.
Radiolabeled molecules used for PK/biodistribution studies and autoradiography in mice and rats include commercial pre-labeled (3H,14C) and in-house labeled (125I, 123I, 99Tc, 111In) molecules, particles or cells.
Frequently Asked Questions (FAQs) in Small Animal Imaging
What types of small animal imaging services do you offer?
Currently, Charles River offers structural MRI, Diffusion Tensor Imaging, pharmacological MRI, Magnetic Resonance Spectroscopy, PET imaging, SPECT imaging and autoradiography for ex vivo tissues.
What is the difference between PET and SPECT imaging?
PET and SPECT imaging are both used to measure metabolic changes and blood flow in the CNS. PET imaging uses 18F, 68Ga or 11C labeled tracers while SPECT imaging uses gamma ray emitters including 99mTc, 111In and 123I.
Can autoradiography be used for in vivo imaging?
Autoradiography is typically used to measure radioactive compound distribution in ex vivo brain tissues and uses either tritated radioligands or 35S-GTP-gamma-S.