MRI in Rodent Models of Brain Disorders

Abstract

Summary: Magnetic resonance imaging (MRI) is a wellestablished tool in clinical practice and research on human neurological disorders. Translational MRI research utilizing rodent models of central nervous system (CNS) diseases is becoming popular with the increased availability of dedicated small animal MRI systems. Projects utilizing this technology typically fall into one of two categories: 1) true "pre-clinical" studies involving the use of MRI as a noninvasive disease monitoring tool which serves as a biomarker for selected aspects of the disease and 2) studies investigating the pathomechanism of known human MRI findings in CNS disease models. Most small animal MRI systems operate at 4.7-11.7 Tesla field strengths. Although the higher field strength clearly results in a higher signalto-noise ratio, which enables higher resolution acquisition, a variety of artifacts and limitations related to the specific absorption rate represent significant challenges in these experiments. In addition to standard T1-, T2-, and T2*-weighted MRI methods, all of the currently available advanced MRI techniques have been utilized in experimental animals, including diffusion, perfusion, and susceptibility weighted imaging, functional magnetic resonance imaging, chemical shift imaging, heteronuclear imaging, and 1 H or 31 P MR spectroscopy. Selected MRI techniques are also exclusively utilized in experimental research, including manganese-enhanced MRI, and cell-specific/molecular imaging techniques utilizing negative contrast materials. In this review, we describe technical and practical aspects of small animal MRI and provide examples of different MRI techniques in anatomical imaging and tract tracing as well as several models of neurological disorders, including inflammatory, neurodegenerative, vascular, and traumatic brain and spinal cord injury models, and neoplastic diseases.

The use of manganese-enhanced MRI for the evaluation of neurodegenerative changes in a rat model of kainic acid- induced excitotoxicity

“…These models help advance the understanding and treatment options of CNS diseases in humans (15). MRI enables longitudinal, noninvasive neurological studies in experimental animal models without sacrificing the animals and provides important anatomical and physiologic information (16).…”

“…MRI enables longitudinal, noninvasive neurological studies in experimental animal models without sacrificing the animals and provides important anatomical and physiologic information (16). After the first MRI study of a rat reported 30 years ago, the number of studies has increased, particularly in relation to the CNS (15)(16)(17).…”

Cell Tracking Technologies for Acute Ischemic Brain Injury

“…Cell tracking technologies for acute ischemic brain injury FNE Gavins and HK Smith systems operate using greater field strengths − 4.7 to 11.7 T. 33 4.7 T machines and above enable the acquisition of higher resolution images with lower cell detection limits, and are required to generate sufficient resolution to image detail of añ 25 g (versus~80 kg) animal. Recently, MRI has become highly useful in real-time, noninvasive imaging of stem cell activity.…”

Current Developments In Mri For Assessing Rodent Models of Multiple Sclerosis

“…There is no single animal model that can faithfully reproduce all the pathological aspects of MS in humans. The available models complement each other to enable investigation of various features commonly observed in the human condition [43].…”