Computed Tomography/Diffusion Weighted Magnetic Resonance Imaging Fogging Effect in the Subacute Stage of Ischemic Cerebral Infarct: A Report of Three Cases

Acute cerebral infarctions usually demonstrate hypodensity on non-contrast computed tomography (CT). However, in some cases, cerebral infarctions may appear to be isodense on imaging conducted during the subacute stage (2-3 weeks after onset). This phenomenon was previously called the fogging effect and has also been reported in magnetic resonance imaging. It is generally reported at T2 image, but can also be observed in diffusion-weighted image (DWI). We report three cases of the fogging effect demonstrated on CT and DWI that was conducted in the subacute stage of ischemic cerebral infarcts. The fogging effect can result in incorrect judgment during the diagnosis and treatment of cerebral infarction patients in the subacute stage. Therefore, it is important that clinicians anticipate this occurrence and necessitates the development of better detection methodologies.