Imaging characteristics of toxoplasmosis encephalitis after bone marrow transplantation: report of two cases and review of the literature

Abstract

Toxoplasmosis encephalitis is a severe, but often misdiagnosed complication in patients after bone marrow transplantation (BMT). We describe the unique computed tomography (CT) and magnetic resonance (MR) imaging features of cerebral toxoplasmosis in two bone marrow recipients and compare them to the cases in the literature. To our knowledge, this is the first report analyzing the appearance of cerebral toxoplasmosis on diffusion-weighted MR imaging (DWI).

Detection of toxoplasmic lesions in mouse brain by USPIO-enhanced magnetic resonance imaging

“…These lesions appear as hypointense/isointense foci on T 1 -weighted images and isointense/hyperintense foci on T 2 -weighted images, representing the necrotic component of the abscess and perifocal edema and the possible presence of hemorrhagic transformation [1][2][3]9]. Typically, the lesions show ring or nodular enhancement after Gd-DTPA injection [17].…”

“…Magnetic resonance imaging (MRI) has been used in the clinical diagnosis of toxoplasmosis encephalitis. Toxoplasmic brain lesions often present as multiple foci with hyperintensity on T 2 -weighted images and with isointensity/hypointensity on T 1 -weighted images [1,2]. Enhancement of these lesions by contrast agent Gd-DTPA is useful for diagnosis but can be variable among different patient populations [1,8,9].…”

“…Toxoplasma gondii is an intracellular protozoan parasite primarily infecting immunocompromised subjects such as AIDS patients and patients who have undergone bone marrow transplantation (BMT) [1][2][3][4]. Clinical diagnosis of toxoplasmosis can be established by serologic tests, detection of parasites and/or relevant DNA in body fluids (i.e., cerebrospinal and bronchoalveolar fluids, blood and urine, etc.)…”

Central Nervous System Infections in Cancer Patients and Hematopoietic Stem Cell Transplant Recipients

“…Ring enhancement, hemorrhage, and edema can be seen with contrast imaging. Alternatively, Toxoplasma lesions in HSCT recipients may fail to enhance; a potential explanation for this lack of enhancement is a blunted inflammatory response in the setting of neutropenia or corticosteroid therapy [322][323][324]. Rarely, imaging will be compatible with meningoencephalitis [304,305].…”

Toxoplasmose cérébrale

“…La prise de contraste et l'oedème périlésionnel peuvent manquer chez le patient transplanté de moelle, surtout en cas de leucopénie marquée [24,25]. Les remaniements hémorragiques (au mieux visualisés sur la séquence en écho de gradient ou T2*) apparaissent généralement sous traitement, mais peuvent être présents d'emblée, notamment chez les patients d'hématologie [26]. L'aspect IRM des lésions est extrême-ment variable d'un patient à l'autre.…”