BACKGROUND AND PURPOSE: CT and MR imaging techniques are frequently used for the diagnosis and progress monitoring of ischemic stroke in clinical practice and research. After stroke, both methods are characterized by a transient pseudo-normalized imaging signal, the so-called fogging phenomenon. This study evaluates potential pathophysiological changes associated with fogging, as well as its influence on the correct determination of the ischemic lesion in a rat stroke model. METHODS: Male spontaneously hypertensive rats were subjected to permanent middle cerebral artery occlusion. Ischemic lesion volume, brain edema and gray scale value spread within the ischemic lesion were determined on T2-weighted MR sequences at days 1, 4, 8, 11 and 29 after stroke onset, and compared with immunohistochemistry for astrogliosis, microglia/macrophage infiltration and angiogenesis. RESULTS: All animals showed MR fogging at days 4, 8 and 11 after stroke. The transient normalization of T2 signals occurred independently from the development of infarct volumes, but coincided well with the spatio-temporal occurrence of necrosis, angiogenesis and microglia/macrophage infiltration. CONCLUSIONS: Our results suggest that the fogging effect reflects the clearance of necrotic tissue within the ischemic lesion and is thus not relevant for the determination of the lesion volume.
BACKGROUND AND PURPOSE: CT and MR imaging techniques are frequently used for the diagnosis and progress monitoring of ischemic stroke in clinical practice and research. After stroke, both methods are characterized by a transient pseudo-normalized imaging signal, the so-called fogging phenomenon. This study evaluates potential pathophysiological changes associated with fogging, as well as its influence on the correct determination of the ischemic lesion in a ratstroke model. METHODS: Male spontaneously hypertensiverats were subjected to permanent middle cerebral artery occlusion. Ischemic lesion volume, brain edema and gray scale value spread within the ischemic lesion were determined on T2-weighted MR sequences at days 1, 4, 8, 11 and 29 after stroke onset, and compared with immunohistochemistry for astrogliosis, microglia/macrophage infiltration and angiogenesis. RESULTS: All animals showed MR fogging at days 4, 8 and 11 after stroke. The transient normalization of T2 signals occurred independently from the development of infarct volumes, but coincided well with the spatio-temporal occurrence of necrosis, angiogenesis and microglia/macrophage infiltration. CONCLUSIONS: Our results suggest that the fogging effect reflects the clearance of necrotic tissue within the ischemic lesion and is thus not relevant for the determination of the lesion volume.
Authors: Pavel Yanev; Peter R Seevinck; Umesh S Rudrapatna; Mark Jrj Bouts; Annette van der Toorn; Karen Gertz; Golo Kronenberg; Matthias Endres; Geralda A van Tilborg; Rick M Dijkhuizen Journal: J Cereb Blood Flow Metab Date: 2016-01-01 Impact factor: 6.200
Authors: Lisette H Deddens; Geralda A F van Tilborg; Kajo van der Marel; Hedi Hunt; Annette van der Toorn; Max A Viergever; Helga E de Vries; Rick M Dijkhuizen Journal: Transl Stroke Res Date: 2017-05-16 Impact factor: 6.829
Authors: Z Alshelh; F Di Pietro; E P Mills; E R Vickers; C C Peck; G M Murray; L A Henderson Journal: Neuroimage Clin Date: 2018-04-13 Impact factor: 4.881
Authors: Maged Goubran; Christoph Leuze; Brian Hsueh; Markus Aswendt; Li Ye; Qiyuan Tian; Michelle Y Cheng; Ailey Crow; Gary K Steinberg; Jennifer A McNab; Karl Deisseroth; Michael Zeineh Journal: Nat Commun Date: 2019-12-03 Impact factor: 14.919