MRI Brain Perfusion is an advanced magnetic resonance imaging (MRI) technique that evaluates the blood flow (perfusion) to different areas of the brain. Perfusion MRI is similar to standard MRI, the major information source of which is brain structure, but it also supplies information on blood flow to brain tissue. This enables doctors to determine if the brain is getting enough oxygen and nutrients.

MRI Brain Perfusion has helped in the diagnosis and management of various neurological diseases such as stroke, brain tumors, cerebral vessel diseases, and in some cases, neurodegenerative diseases. If there is an increase or decrease that is significant, it is detected and can help the doctor determine whether the tissue is viable, the severity of the condition, plan treatment, and determine its effectiveness.

What is MRI Brain Perfusion?

MRI Brain Perfusion is a special MRI scan that assesses blood flow that passes through the brain. It provides relevant information about brain haemodynamics based on the flow of blood in brain tissue. The exam can be done in several different ways:

• Dynamic Susceptibility Contrast (DSC) is a gadolinium-based contrast study of blood flow.
• Dynamic Contrast-Enhanced (DCE) MRI uses a contrast agent to evaluate the permeability and blood vessels.
• Arterial Spin Labeling (ASL): A non-contrast technique that uses magnetically labeled blood as a natural tracer to measure cerebral blood flow.

The scan could be performed and provide numerical results such as:

• Cerebral Blood Flow (CBF)
• Cerebral Blood Volume (CBV)
• Mean Transit Time (MTT)
• Time to Peak (TTP)

The measurements are used to help evaluate brain function, to determine if there are any abnormalities of blood flow, and to decide whether diseased brain tissue is different from normal.

Why is MRI Brain Perfusion Performed?

MRI Brain Perfusion is recommended in certain cases where the evaluation of CBF is important. When carrying out functional imaging, information is not available in the routine MRI; in some cases, it can be very useful. Common indications include:

Evaluation of Stroke

• Acute ischemic stroke: Detection.
• Differentiation of the ischemic penumbra (brain tissue that can be preserved if treated in time)
• Determine the amount of impaired circulation

Brain Tumor Assessment

• The ability to distinguish recurrent tumors from treatment-induced changes (radiation necrosis, etc.)
• Measurements of tumour grade and vascularity
• Supporting treatment and post-treatment planning.

Neurodegenerative Disorders

• Supporting the evaluation of conditions such as Alzheimer's disease and other dementias
• Assessing regional changes in cerebral blood flow

Cerebrovascular Disorders

• Evaluating chronic cerebrovascular disease
• Assessing reduced blood flow caused by narrowing or blockage of brain arteries

Epilepsy Evaluation

• Helping identify abnormal brain regions associated with difficult-to-control seizures as part of a comprehensive evaluation

Investigation of Neurological Symptoms

The scan may also be recommended for patients experiencing:

• Sudden weakness or numbness
• Persistent headaches
• Memory problems
• Speech difficulties
• Unexplained neurological symptoms

What Does MRI Brain Perfusion Detect?

MRI Brain Perfusion provides information regarding the blood flow of the brain tissue and can be beneficial in identifying abnormalities that may not be identified in a regular MRI. May assist with a diagnosis or evaluation of:

• Acute ischemic stroke
• Brain tumors
• Treatment-related radiation necrosis
• Cerebrovascular disease
• Alzheimer's disease and other dementias
• Arteriovenous malformations (AVMs)
• Other vascular abnormalities
• Areas of abnormal cerebral blood flow associated with epilepsy

Benefits of MRI Brain Perfusion

Functional Brain Assessment

Measures the circulation of blood through brain structures, not just the structure of the brain tissue itself.

Early Detection

Identifies cerebral circulation changes before structural changes.

No Radiation Exposure

MRI does not use ionising radiation.

Improved Stroke Evaluation

Aids in identifying non-reversible brain damage and brain tissue that can be saved if it can be treated in time.

Better Tumor Assessment

Gives useful information for tumor grading, treatment planning, and evaluating response to treatment.

Flexible Imaging Options

May be done with or without contrast.

Quantitative Analysis

Measures cerebral blood flow objectively, which helps to make accurate diagnostic and therapeutic decisions.

Risks and Considerations

MRI Brain Perfusion is generally safe for most people; the following are some of the precautions taken.

MRI Safety

 Certain implanted medical devices, such as some pacemakers, cochlear implants, aneurysm clips, or metallic foreign devices, may not be compatible with MRI.

Contrast-Related Risks

Gadolinium-based contrast medium is usually very safe. Some patients may experience mild side effects, including nausea, headache, or skin rash. Inhalation of the substance does not cause any severe allergic reactions.

Kidney Function

Patients with very poor kidney function may need an evaluation before receiving gadolinium contrast to minimize the uncommon risk of nephrogenic systemic fibrosis (NSF).

Claustrophobia

Anxiety sometimes occurs within the MRI scanner for some patients. The use of mild sedation may be necessary.

Motion During the Scan

Motion of the patient can degrade the image quality, and it is important to stay still during the study.

Conclusion

MRI Brain Perfusion provides functional information as well as traditional MRI and is currently in use for brain blood flow. It is a very helpful modality to diagnose ‘stroke of the month', brain tumor, cerebrovascular disease, epilepsy, and certain neurodegenerative diseases. The MRI Brain Perfusion detects changes in brain blood flow early in the disease process, which can aid in accurate diagnosis, determine appropriate therapy, and monitor disease progression. Your doctor might wish to have this test to get detailed information on the flow of blood to your brain and make an appropriate treatment recommendation.