TY - JOUR
T1 - Neuropathological correlate of the "concentric target sign" in MRI of HIV-associated cerebral toxoplasmosis
AU - Mahadevan, Anita
AU - Ramalingaiah, Arvinda Hanumantapura
AU - Parthasarathy, Satishchandra
AU - Nath, Avindra
AU - Ranga, Udaykumar
AU - Krishna, Shankar Susarla
PY - 2013/8
Y1 - 2013/8
N2 - Cerebral toxoplasmosis is a frequent cause of focal brain lesions in the setting of immunodeficiency states, particularly acquired immune deficiency syndrome (AIDS), and magnetic resonance imaging (MRI) is an important diagnostic modality to differentiate toxoplasmosis from tuberculoma, and primary central nervous system lymphoma with diverse therapeutic implications. Several imaging patterns have been described in cerebral toxoplasmosis. The "concentric target sign" is a recently described MRI sign on T2-weighted imaging of cerebral toxoplasmosis that has concentric alternating zones of hypo- and hyperintensities. It is believed to be more specific than the well-known "eccentric target sign" in the diagnosis of cerebral toxoplasmosis and hence more useful in differentiation from other focal brain lesions in the context of AIDS. The concentric target sign, seen in deep parenchymal lesions, is distinct from the surface-based cortical "eccentric" target sign. The histopathological correlate of the latter has been recently described, but that of the concentric target sign is not known. In this study we describe the neuropathological correlate of this concentric target sign from the postmortem of a 40-year-old man with AIDS-associated cerebral toxoplasmosis. The concentric alternating zones of hypo/hyper/iso/intensities corresponded to zones of hemorrhage/fibrin-rich necrosis with edema/coagulative compact necrosis/inflammation with foamy histiocytes admixed with hemorrhage forming the outermost zone, respectively. The exclusive specificity of this sign in cerebral toxoplasmosis remains to be further elucidated. © 2013 Wiley Periodicals, Inc.
AB - Cerebral toxoplasmosis is a frequent cause of focal brain lesions in the setting of immunodeficiency states, particularly acquired immune deficiency syndrome (AIDS), and magnetic resonance imaging (MRI) is an important diagnostic modality to differentiate toxoplasmosis from tuberculoma, and primary central nervous system lymphoma with diverse therapeutic implications. Several imaging patterns have been described in cerebral toxoplasmosis. The "concentric target sign" is a recently described MRI sign on T2-weighted imaging of cerebral toxoplasmosis that has concentric alternating zones of hypo- and hyperintensities. It is believed to be more specific than the well-known "eccentric target sign" in the diagnosis of cerebral toxoplasmosis and hence more useful in differentiation from other focal brain lesions in the context of AIDS. The concentric target sign, seen in deep parenchymal lesions, is distinct from the surface-based cortical "eccentric" target sign. The histopathological correlate of the latter has been recently described, but that of the concentric target sign is not known. In this study we describe the neuropathological correlate of this concentric target sign from the postmortem of a 40-year-old man with AIDS-associated cerebral toxoplasmosis. The concentric alternating zones of hypo/hyper/iso/intensities corresponded to zones of hemorrhage/fibrin-rich necrosis with edema/coagulative compact necrosis/inflammation with foamy histiocytes admixed with hemorrhage forming the outermost zone, respectively. The exclusive specificity of this sign in cerebral toxoplasmosis remains to be further elucidated. © 2013 Wiley Periodicals, Inc.
KW - AIDS
KW - MRI
KW - T2 WI
KW - concentric target sign
KW - neuropathology
KW - toxoplasmosis
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U2 - 10.1002/jmri.24036
DO - 10.1002/jmri.24036
M3 - Article
C2 - 23440973
AN - SCOPUS:84882585311
SN - 1053-1807
VL - 38
SP - 488
EP - 495
JO - Journal of Magnetic Resonance Imaging
JF - Journal of Magnetic Resonance Imaging
IS - 2
ER -