Evaluation of imaging methods in cerebral toxoplasmosis

Abstract

Cerebral toxoplasmosis is a parasitic disease resulting, in most cases, from a reactivation of a latent cyst with Toxoplasma gondii. The disease mainly affects immunosuppressed individuals, such as HIV (human immunodeficiency virus)-infected patients. Diagnosis is based on specialized antibody testing, clinical symptoms, neuroimaging methods, and histological examination. The gold standard for diagnosis is a brain biopsy, but more often the response to treatment seen in clinical symptoms and neuroimaging studies is sufficient. The imaging features support the diagnosis of cerebral toxoplasmosis and help assess the effectiveness of treatment.

Keywords: cerebral toxoplasmosis; computed tomography; encephalitis; magnetic resonance imaging; neuroimaging.

Figure 1

T1-weighted axial post-contrast image shows a lesion with ring enhancement and an additional peripheral nodular enhancement within the lesion; this is referred to as an eccentric target sign typical in neurotoxoplasmosis

Figure 2

Coronal T2-weighted MRI of the brain shows a concentric alternating zone of hypo-/hyper /isointense signal, surrounded by perilesional oedema, which, with the accompanying T1 post-contrast images, are typical features of neurotoxoplasmosis