Which imaging finding is commonly seen in cerebral toxoplasmosis?

Which imaging finding is commonly seen in cerebral toxoplasmosis?

• A. Ring-enhancing lesions on head CT/MRI
• B. Diffuse meningeal enhancement
• C. Normal imaging
• D. Basilar meningitis

Answer: (A)

The imaging pattern most characteristic of cerebral toxoplasmosis is ring-enhancing lesions seen on contrast-enhanced head CT or MRI. These rings come from focal areas of necrosis surrounded by inflammatory tissue that takes up contrast, creating a bright ring around a darker center. In people with advanced immunosuppression, especially HIV with low CD4 counts, toxoplasma gondii commonly reactivates and forms multiple such lesions, often located in the basal ganglia or at the corticomedullary junction. This combination of multiple lesions and ring enhancement in the appropriate clinical context is the hallmark finding. Other patterns—like diffuse meningeal enhancement—would suggest meningitis rather than focal parenchymal infection; a normal imaging study makes a cerebral focal process unlikely; basilar meningitis refers to meningeal involvement along the base of the brain rather than discrete parenchymal rings.

The imaging pattern most characteristic of cerebral toxoplasmosis is ring-enhancing lesions seen on contrast-enhanced head CT or MRI. These rings come from focal areas of necrosis surrounded by inflammatory tissue that takes up contrast, creating a bright ring around a darker center. In people with advanced immunosuppression, especially HIV with low CD4 counts, toxoplasma gondii commonly reactivates and forms multiple such lesions, often located in the basal ganglia or at the corticomedullary junction. This combination of multiple lesions and ring enhancement in the appropriate clinical context is the hallmark finding.

Other patterns—like diffuse meningeal enhancement—would suggest meningitis rather than focal parenchymal infection; a normal imaging study makes a cerebral focal process unlikely; basilar meningitis refers to meningeal involvement along the base of the brain rather than discrete parenchymal rings.