Name : Morteza
Family : Sanei Taheri
Affiliation :Radiology Department,Shohada Tajrish Hospital,SBMU
Academic Degree : Associate Professor of Radiology
Resident : Mirhadi Razavian
Gender : Female
Age : 26
A 26 y/o female HIV positive with headache
MR imaging of the brain revealed a widespread distribution of hyperintense lesions on both fluid-attenuated inversion recovery (FLAIR) and T2-weighted images . The lesions were situated primarily at the gray matter–white matter interfaces and in the basal ganglia. On T1-weighted images, many of the larger lesions demonstrated increased signal intensity at the peripheries ,a somewhat irregular and shaggy appearance, signal intensity was increased to a greater degree than usual, a finding that may indicate a larger amount of subacute mural hemorrhage or increased protein content.also revealed prominent gyral hemorrhage at left parietal lobe and internal hemorrhage at some leisions.
•primary CNS lymphoma: see lymphoma vs toxoplasmosis
•other infections oCNS tuberculoma: see CNS tuberculosis
Discussion (Related Text)
Cerebral toxoplasmosis is an opportunistic infection which typically affects patients with HIV/AIDS, and is the most common cause of cerebral abscess in these patients. Clinical presentation
In immunocompetent patients, acute encephalitis is extremely rare. Even in the immunocompromised symptoms are typically vague and indolent. Development of new neurological symptoms in these patients should raise high suspicion of cerebral toxoplasmosis.The most common presenting symptom in patients with cerebral toxoplasmosis is headache. This is often accompanied by altered mental status and fever (4). Patients also may present with seizures, cranial nerve abnormalities, visual field defects, and sensory disturbances. Focal neurologic signs are common and include motor weakness and speech disturbances.
Typically cerebral toxoplasmosis manifest as multiple lesions, with a predilection for the basal ganglia,thalami, and corticomedullary junction .
Typically, cerebral toxoplasmosis appears as multiple hypodense regions predominantly in the basal ganglia and at the corticomedullary junction. However, they may be seen in the posterior fossa. Size is variable, from less than 1 cm to more than 3 cm, and there may be associated mass effect.
•enhancement: following administration of contrast there is nodular or ring enhancement which is typically thin and smooth .
•double-dose delayed scan: may show a central filling on delayed scans
•calcification: seen in treated cases; may be dot-like or thick and 'chunky'
•T1: may be difficult to identify, but are typically isointense or hypointense .
ointensity is variable, from hyperintense to isointense 2-5
hyperintense: thought to represent necrotising encephalitis
isointense: thought to represent organising abscess 4
olesions are surrounded by perilesional oedema
•T1 C+ (Gd): lesions often demonstrate ring enhancement or nodular enhancement
o increased lactate
o increased lipids
o reduced Cho, Cr and NAA
o Increased lipid-lactate peak is characteristic, however choline peak also may be seen in few cases.
These lesions usually are hypointense on T1-weighted MR images, but they may show peripheral hyperintensity, a feature that helps distinguish toxoplasmosis from lymphoma. The lesions usually have high or mixed signal intensity on T2-weighted and FLAIR images. On diffusion-weighted images, the lesions may show peripheral hyperintensity in the presence of hemorrhage within their walls; however, restricted diffusion within the central portion of the lesions, a finding in pyogenic abscesses, is uncommon.
Like toxoplasmosis, CNS lymphoma has a predilection for the basal ganglia. Both show varied patterns of enhancement, edema, and mass effect on CT images and increased signal intensity on T2-weighted MR images. Unifocal and multifocal involvement also are seen in both conditions. Lesions in lymphoma tend to be more locally infiltrative; th
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