Arachnoid cyst MRI

An arachnoid cyst is a cerebrospinal fluid (CSF)-filled sac located between the brain or spinal cord and the arachnoid membrane, one of the three meninges that cover the brain and spinal cord. These cysts are typically benign and non-cancerous but can cause symptoms if they grow large enough to compress surrounding neural structures.

Causes

The exact cause of arachnoid cysts is often unknown, but they are generally categorized into two types based on their origin:

• Primary (Congenital): These cysts are present at birth and arise due to developmental abnormalities during the formation of the brain and spinal cord.
• Secondary (Acquired): These cysts develop later in life due to factors such as head injury, meningitis, tumors, or brain surgery.

Symptoms

Many arachnoid cysts are asymptomatic and discovered incidentally during imaging studies for other conditions. However, symptomatic cysts can lead to various neurological symptoms, which depend on their size and location. Common symptoms include:

• Headache
• Nausea and vomiting
• Seizures
• Hydrocephalus (accumulation of CSF in the brain)
• Developmental delays in children
• Balance and coordination problems
• Hearing or vision disturbances
• Cognitive and behavioral changes

Diagnosis

The diagnosis of arachnoid cysts typically involves imaging studies to visualize the cyst and its impact on surrounding brain structures. Common diagnostic methods include:

• Magnetic Resonance Imaging (MRI): Provides detailed images of the brain and spinal cord, helping to identify the cyst’s size, location, and effect on adjacent tissues.
• Computed Tomography (CT) Scan: Useful for identifying cysts, especially in emergency settings. It provides less detail than MRI but is quicker.
• Ultrasound: Occasionally used in infants with open fontanelles (soft spots) to visualize cysts.

Treatment

The treatment approach for arachnoid cysts depends on the presence and severity of symptoms. Options include:

• Observation: Asymptomatic or minimally symptomatic cysts are often monitored with regular imaging to ensure they do not grow or cause problems.
• Medications: Symptomatic treatment for headaches, seizures, or other specific symptoms.
• Surgical Intervention: Considered for cysts causing significant symptoms or complications. Surgical options include:
  • Endoscopic Fenestration: A minimally invasive procedure where small openings are created in the cyst to allow CSF to flow into the normal pathways.
  • Microsurgical Removal: Complete or partial removal of the cyst, usually for more accessible or problematic cysts.
  • Shunting: Involves inserting a shunt to divert CSF from the cyst to another body cavity (e.g., the abdomen) to relieve pressure.