Intracranial magnetic resonance imaging artifacts and pseudolesions in dogs and cats

Normal anatomic variation, study design, external factors, and tissue characteristics can all influence the manifestation of structures on magnetic resonance images (MRI). For the purpose of this review, imaging artifacts are considered to be nonpathologic abnormalities resulting from study design, intrinsic tissue characteristics, or external factors, while MRI pseudolesions are due to normal anatomic variation. Awareness of imaging artifacts and pseudolesions, as well as normal anatomic structures, is important when determining pathologic vs. normal or clinically insignificant abnormalities. The purpose of this report is to examine the literature to compile a review of selected artifacts and pseudolesions that are commonly encountered when imaging the canine and feline brain.