Introduction:
A rich vascular network supplies the brain. When these blood vessels do not develop normally, they result in conditions known as vascular malformations. Since they develop in the brain, they are also known as intracerebral vascular malformations. These abnormal blood vessels would lead to altered blood flow in the brain. Vascular malformations are usually congenital (develop at birth). Vascular malformations are mostly asymptomatic until they rupture or expand in size. Hence they remain undiagnosed in most cases, or they may be accidentally discovered in an imaging procedure.
What Are the Various Types of Vascular Malformations?
The four main types of vascular malformation are described below:
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Arteriovenous Malformation (AVM): This is a potentially fatal condition due to the abnormal connection between the arteries and veins in the brain. This disrupts the average circulation and oxygen supply to the brain tissues. A ruptured AVM is a life-threatening condition.
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Cavernous Angiomas: Cavernous angiomas are capillary (small-sized blood vessels) vascular abnormalities. They do not affect the functioning of the brain; however, they lead to many severe problems, such as seizures, headaches, and even stroke.
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Capillary Telangiectasias: Capillary telangiectasias are abnormally enlarged capillaries in the brain. They are usually asymptomatic unless they grow in size or rupture accidentally.
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Venous Malformation: It is a congenital malformation of the brain where the veins are irregularly arranged.
What Are the Causes of Vascular Malformation?
Brain vascular malformations are developmental lesions that are present mostly at birth. These abnormalities progressively increase in size and cause associated symptoms. Individuals with abnormalities in the vascular structure or inflammatory conditions are more prone to developing vascular malformations.
What Is Capillary Telangiectasia?
The term telangiectasia means broken or enlarged blood vessels. Capillary telangiectasia is a vascular malformation in the brain where the small-sized blood vessels (capillaries) are enlarged. They are the second most common vascular malformations found in the brain. Capillary telangiectasia is usually asymptomatic and is often diagnosed incidentally on MRI (magnetic resonance imaging). The presence of normal brain tissue amidst the enlarged blood vessels is a characteristic finding of capillary telangiectasia. They can occur in the brain or even in the spinal cord. They may even occur with other types of vascular malformations.
What Are the Symptoms of Capillary Telangiectasia?
Capillary telangiectasia is usually found in the third or fourth decades of life. They rarely cause any symptoms. They may appear as a solitary lesions or may even be associated with other developmental anomalies. Larger lesions may present with headaches, blurred vision, hearing difficulties, nausea, speech issues, seizures, altered mental condition, or even paresthesia.
What Is Brain Imaging?
Brain imaging or neuroimaging is a rapidly evolving diagnostic field that employs computational methods to evaluate the central nervous system. It can be used to assess the structure and function of the brain and spinal cord, based on which they are classified as structural neuroimaging and functional neuroimaging. Brain imaging is being increasingly used in various intracranial disorders. It helps identify the cause and guides treatment procedures, thereby influencing the outcome and prognosis.
What Are the Types of Brain Imaging?
The most commonly used brain imaging techniques are described below:
1. Magnetic Resonance Imaging (MRI):
MRI is a noninvasive test that uses magnetic fields and radio waves to assess the internal structures of the body. MRI is the most preferred neuroimaging technique due to its high-resolution images. In addition, it is the most preferred imaging technique for evaluating neurovascular bundles. The use of a contrast agent along with MRI increases the specificity to a great extent.
2. Functional Magnetic Resonance Imaging (FMRI):
It is a noninvasive test used to determine brain activity (functioning). It evaluates the changes in the blood flow and brain oxygen level to determine the metabolic functions of the brain. It is extremely beneficial to diagnose various neurological conditions adversely affecting the normal functioning of the body. It is a vital tool in neurosurgery, particularly when the surgical intervention involves or is near a critical functional area.
3. Computed Tomography (CT):
CT scan is a diagnostic procedure to view the internal organs and other body parts. The advantage of CT is the ability to obtain images in multiple planes and also reconstruct the image in three-dimensional form. Advanced CT procedures include contrast CT, high-resolution computed tomography (HRCT), and multidetector computed tomography (MDCT).
4. Positron Emission Tomography (PET):
A PET scan is used to assess and evaluate the functioning mechanisms of the organs and tissues based on their metabolic and biochemical activity. It uses a radioactive tracer that has a high affinity to glucose. Areas with increased metabolic activity are found to have a high glucose content, and hence there is an increased uptake of the radioactive tracer in these cells. Since glucose is the primary fuel for the brain, the radiotracers increasingly accumulate in the brain. Hence PET scan is highly beneficial in assessing brain function.
5. Electroencephalography (EEG):
EEG is used to detect brain activity. Small electrodes are placed on the scalp to record the activity by detecting the brain waves. These activities will be recorded in the form of a graph. EEG is beneficial for assessing anxiety, trauma, seizures, or sleep disorders.
6. Functional Near-Infrared Spectroscopy (fNIRS):
This technique is used to measure oxygen saturation in the brain. It employs infrared light to evaluate the oxyhemoglobin levels in the blood.
What Is the Role of Imaging Techniques in Diagnosing Capillary Telangiectasia?
Magnetic resonance imaging (MRI) is ideal for imaging capillary telangiectasia. Contrast MRI is more specific in diagnosing capillary telangiectasia. They are usually incidental findings on MRI. MRI is performed with two predominant image sequences that are T1 and T2 weighted images depending on the time taken for the magnetic pulse to generate the image. Capillary telangiectasia usually appears hypo-intense or iso-intense on T1 images, hyper-intense in T2, and low signal intensity in gradient-echo imaging. Hemorrhage (bleeding) and calcifications (calcium deposits) are rare findings in capillary telangiectasia. Enlarged blood vessels are a prominent finding. Gradient-echo imaging is a simpler and more efficient technique in MRI to detect capillary telangiectasia.
Computed tomography (CT) and angiography are inconclusive in diagnosing capillary telangiectasia. Contrast CT may demonstrate capillary telangiectasia as an enhanced (bright) lesion with the presence or absence of calcification. Negative findings in CT do not rule out capillary telangiectasia, as they usually are occult lesions.
Conclusion:
Capillary telangiectasia is a benign vascular malformation in the brain and spinal cord. Though asymptomatic, capillary telangiectasia mandates periodic follow-up to ensure the stability of the lesion. Computed tomography and angiography are not much beneficial in diagnosing capillary telangiectasia. Contrast MRI is the gold standard in diagnosing and differentiating capillary telangiectasia from other vascular malformations. Treatment of capillary telangiectasia is not warranted till symptomatic.
