Magnetic resonance imaging and cerebrospinal fluid immunoassay in the diagnosis of cerebral schistosomiasis: experience in Southwest China

Imaging of parasitic infections of the central nervous system

Parasitic infections of the central nervous system (CNS) have increased over the last couple of decades, partly due to a drop in the living conditions of large populations in the world and the AIDS epidemic. Parasitic infections of the CNS are indolent and often life threatening, hence, an early diagnosis is imperative. While brain biopsy and laboratory analysis remain the gold standard for diagnosis, neuroimaging contributes significantly to diagnosis and follow-up. Imaging can demonstrate the extent of infection and complications and possibly, the type of parasitic infection when characteristic features are evident. The disappearance of the parasite or inflammation, gliosis, and/or calcification suggest a therapeutic response. The initial experience of the CT scan has been greatly enhanced by MRI which is currently the imaging modality of choice. This has been due to the greater tissue contrast resolution of MRI and its ability to detect subtle changes in the tissue parenchyma. Advanced techniques such as diffusion-weighted imaging (DWI), perfusion imaging (PI), MR angiography (MRA), and MR spectroscopy (MRS) have been used to improve the sensitivity for characterizing the type, viability, and burden of the parasites and the host tissue response. Additionally, it is possible to demonstrate the complications of the primary infection and those secondary to treatment, in some cases.

Pseudotumoral form of neuroschistosomiasis: report of three cases in Ganzi, China

The authors report three rare cases of neuroschistosomiasis lacking extracranial involvement. No parasitic eggs were detected in the stool with the Kato-Katz thick smear methods. Computed tomography of the brains showed hypodense signals, and magnetic resonance imaging showed isointense signals on T1-weighted images, hyperintense signals on T2-weighted images, and intensely enhancing nodules in the brain after intravenous administration of gadolinium. High-grade gliomas were suspected, and operations or radiosurgery was performed. Cerebral schistosomiasis was confirmed in all cases by biopsy of the brain lesions, revealing granulomas containing embedded Schistosoma japonicum eggs. All cases were definitively diagnosed as brain schistosomiasis japonica. Praziquantel and corticosteroids were administered, and the prognoses were good for all case patients. Although the aforementioned pattern of imaging examinations is not present in all cases of neuroschistosomiasis, a diagnosis of neuroschistosomiasis should be considered when this pattern of imaging is observed; cerebrospinal fluid serological exams are also recommended.