What are the causes of ring-enhancing lesions on brain imaging, specifically in cases of cerebral (Central Nervous System) pathology?

From the Guidelines

Ring-enhancing lesions on brain imaging are typically caused by brain abscesses, brain tumors such as glioblastoma, metastases, and demyelinating diseases like multiple sclerosis, as well as other conditions including neurocysticercosis, toxoplasmosis, and tuberculomas 1, 2, 3.

Key Causes of Ring-Enhancing Lesions

• Infectious causes: brain abscesses, neurocysticercosis, toxoplasmosis, and tuberculomas
• Neoplastic causes: glioblastoma, metastases, and primary CNS lymphoma
• Inflammatory causes: multiple sclerosis, and other demyelinating diseases
• Other causes: radiation necrosis, and vascular malformations

It is essential to approach these lesions with caution and consider a thorough diagnostic workup, including MRI with contrast, to determine the underlying cause 4, 5. In some cases, a biopsy may be necessary to establish a definitive diagnosis.

Diagnostic Approach

• MRI with contrast to evaluate lesion characteristics and location
• Biopsy for definitive diagnosis in uncertain cases
• Consideration of patient's medical history, symptoms, and laboratory results

Treatment will depend on the underlying cause, and may involve antibiotics such as ceftriaxone or metronidazole for brain abscesses, anticonvulsants like levetiracetam for seizure control, or corticosteroids like dexamethasone to reduce inflammation 6, 7. In cases of brain tumors, treatment may involve surgery, radiation, or chemotherapy with medications like temozolomide. A comprehensive evaluation by a neurologist or neurosurgeon is crucial to determine the best course of treatment 8, 9.

From the Research

Causes of Ring-Enhancing Lesions

The causes of ring-enhancing lesions on brain imaging are varied and can be attributed to several factors, including:

• Infections, such as pyogenic abscess and tuberculosis 10, 11, 12
• Tumors, including primary neoplasms like glioma and metastasis 10, 11
• Demyelinating diseases, such as multiple sclerosis 11
• Treatment-related conditions and hematoma 13
• Neurocysticercosis and CNS lymphoma 10
• Fungal infections and toxoplasma cysts 14

Clinical Presentation

The clinical presentation of ring-enhancing lesions can be non-specific, with symptoms such as:

• Headache 10
• Seizures 10
• Altered mental status 14
• Hyperglycaemia and community-acquired pneumonia 14

Diagnostic Approach

The diagnostic approach to ring-enhancing lesions involves:

• Radiological investigations, such as MRI and CT scans 10, 11, 13, 12
• Biopsy, which can be performed using invasive or minimal invasive techniques 10, 14
• Clinical data and medical history, including information on immunocompromised status 10, 14, 12
• Laboratory tests, such as RPR titres and CD4 count 14

Imaging Characteristics

The imaging characteristics of ring-enhancing lesions can vary, with:

• T2 hypointensity associated with specific pathologies, such as abscesses and metastases 11
• Central homogeneity on T2 and multiplicity of lesions, which can aid in differentiating between etiologies 11
• Diffusion-weighted images, which can help distinguish between abscesses and other pathologies 11