Imaging of infectious and inflammatory cystic lesions of the brain, a narrative review

ABSTRACT

Introduction

Intracranial cysts and cyst-like intracranial lesions are common findings on neuroimaging with a wide range of etiologies. Oftentimes, cystic intracranial lesions are benign but in some parts of the world, infectious etiologies for cystic lesions in the brain are quite common. Prompt identification of the cause of a cystic brain lesion is paramount in determining appropriate treatment if indicated.

Areas covered

In this narrative review article, the authors present a comprehensive description of cystic lesions of infectious or inflammatory etiology. Imaging descriptions are provided for each type of cystic lesion as well as several representative images.

Expert opinion

The majority of diagnoses may be identified by CT and MR imaging. Yet some pathologies are still unable to be determined through standard imaging techniques and biopsy remains necessary for definitive diagnosis in some cases. Advanced neuroimaging such as metabolic/nuclear imaging and advanced MR hold promise with improved diagnostics but are not often available in geographic regions where these illnesses are endemic.

KEYWORDS:

• Intracranial cyst
• neurocysticercosis
• cerebral abscess
• hydatid disease
• MRI
• cystic demyelination

Article highlights

• Acquired cystic lesions in the brain are often due to infectious pathologies

• Neurocysticercosis (NCC) is the most common parasitic infection in the brain and the most common cause of infective brain cysts

• Imaging in NCC varies depending upon life cycle of the organism and the host response, and cysts may be both intraparenchymal and/or extraparenchymal

• Appropriate diagnosis of NCC, staging, and location (intra vs. extraparenchymal) is essential to determination of appropriate management

• Other infections which may lead to cyst formation of cyst-like structures include pyogenic brain abscess, tuberculous abscess, echonococcus (hydatid disease), toxoplasmosis, amebic abscess, coeneurosis, crytococcocis, and other rare bacterial, parasitic, fungal diseases

• Post-infectious and inflammatory diseases, such as demyelinating diseases, and Neurosarcoidosis, may lead to cystic lesions

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Article highlights

• Historically considered a benign component of aging, hearing loss in recent years has been associated with cognitive decline, dementia, and poor brain health in older adults

• Hearing loss can have adverse effects on brain structure and function and can lead to loneliness and late-life depression

• Accumulating evidence suggests that hearing treatment may improve cognitive outcomes in older adults, though there are important limitations to such findings

• Preliminary studies also provide evidence that hearing treatment may reverse specific neuroplastic changes associated with chronic hearing loss

• Further research is needed to determine whether hearing treatment is effective for the prevention and/or treatment of current cognitive decline

• Given the potential benefits of hearing treatment on cognitive and neural outcomes, there is an urgent need to provide increased access to hearing care

Additional information

Funding

This paper was not funded.