The use of MRI to assist the section selections for classical pathology assessment of neurotoxicity

Quantification and reproducibility assessment of the regional brain T2 relaxation in naïve rats at 7T

“…The statistical power analysis revealed that only 3–4 subjects are needed per single test group to detect a 5% difference with the power of 0.8 in most brain areas. However, in our previous studies using known neurotoxicants, such as kainic acid, hexachlorophene, trimetyltin, and others, we found that T 2 changes due to neurotoxicity had been much higher . Therefore, we expect that in properly executed studies three animals per test group should be enough to detect toxicity‐related changes, provided that all animals respond to the toxic exposure.…”

“…Qualitative T 2 ‐weighted magnetic resonance imaging (MRI) as well as quantitative T 2 mapping of the brain are widely used in clinical practice and nonclinical research to study many neurological diseases, therapeutic efficacy, and drug‐induced and environmental neurotoxicity . The high quality of an image with virtually no geometrical distortion, high signal‐to‐noise ratio, and lower sensitivity to subject motion results in advantages of spin‐echo‐based T 2 relaxation contrast imaging over other popular methods like diffusion‐weighted, diffusion tensor, and perfusion imaging in studies of neuronal tissue perturbations.…”

“…The use of quantitative T 2 mapping was recently proposed to assess the neurotoxicity in nonclinical studies in rats . As a marker of neurotoxicity, this parameter is highly sensitive and easily quantifiable .…”

“…As a marker of neurotoxicity, this parameter is highly sensitive and easily quantifiable . The analysis of T 2 relaxation both quantitatively as T 2 mapping and qualitatively as T 2 ‐weighting imaging has been applied to some extent in different animal models in the neurotoxicological research . However, there is a gap in the scientific literature addressing the baseline behavior—the stability and reproducibility of T 2 relaxation between animals in different anatomical areas of the brain and over time in longitudinal studies.…”

Regulatory Forum Opinion Piece*: Imaging Applications in Toxicologic Pathology—Recommendations for Use in Regulated Nonclinical Toxicity Studies

“…Histopathology confirmed that the altered MRI signals were consistent with well-circumscribed foci of neuronal cell degeneration/necrosis accompanied by gliosis ( Figure 15). The conclusion of this experiment was that the quick analysis of fixed organs by an MRI system can provide useful information for the selection of sampling sites for histopathological slide preparation, especially in complex and functionally heterogeneous organs such as the brain (Hanig et al 2014).…”