CT Scan

A CT scan of the brain is a diagnostic imaging technique used to study the details of the head. CT scan takes a series of X-rays and computes the same to produce detailed images of the head. The procedure is usually done as an outpatient procedure. It usually takes about 15 minutes to complete the scan.

Contrast dye helps highlight some areas better on CT images. The dye is given through an intravenous line inserted into a vein of your arm or hand. Contrast study will help to define the pathologies like brain tumour, abscess, aneurysm and others.

Drawbacks

• Claustrophobia and discomfort
• Allergy to the IV contrast dye
• Radiation exposure (Not to be used in pregnant ladies)

PET – CT

PET CT scans provide pictures of radioactivity of brain by measuring radioactive isotopes that are injected into the bloodstream. PET scans of the brain are used to detect tumours, or diseased tissue.

A low-level radioactive isotope is injected into the bloodstream and its uptake in the brain is measured. The gamma rays in the body’s tissues are detected by the sensors which are processed by a computer and the information is transferred to video monitor or on film.

MRI Scan

MRI uses radio waves generated by a powerful magnetic field to produce detailed images of body tissues. Using different sequences of magnetic pulses, MRI can show anatomical images of the brain or spinal cord. MRI is used to diagnose most of the pathologies in the brain like tumours, stroke, inflammation, infection, vascular irregularities, changes causing epilepsy and some neurodegenerative disorders. A contrast dye may be injected into the vein to enhance the clarity and to define the pathology better.

The individual lies on a special table that slides into the tube and will be asked to remove jewellery, spectacles, removable dental work, metals and other items that might interfere with the magnetic imaging. Patients with implanted devices like pacemakers which interfere with magnetic field cannot undergo MRI. MRI is done as an out-patient procedure and may take 30 – 60 minutes.

Drawbacks

• Claustrophobia
• Allergy and renal toxicity of dye
• Patients with meal implants, MRI is not possible
• Difficult in obese patients

Angiogram

Angiogram is a diagnostic procedure that involves injecting dye into the arteries or veins to detect any abnormalities in the arteries or veins. Angiograms are usually performed in a hospital setting and may take up to 2 hours, followed by a 6- to 8-hour resting period. A catheter is inserted into an artery located near the groin. The catheter is threaded through the body and into an artery in the neck. Dye is injected which travels through the bloodstream into the neck and head. A series of x-rays images are taken and the blood vessel path is traced and studied.

The individual lies on a special table that slides into the tube and will be asked to remove jewellery, spectacles, removable dental work, metals and other items that might interfere with the magnetic imaging. Patients with implanted devices like pacemakers which interfere with magnetic field cannot undergo MRI. MRI is done as an out-patient procedure and may take 30 – 60 minutes.

Uses of angiogram

• To detect blockage or narrowing of an artery or vein.
• To detect location and size of an aneurysm or vascular malformation.
• Angiograms are used in embolic strokes to unblock the artery using a clot retriever.
• To determine the blood supply of a tumour prior to surgery or embolectomy

In situations where cerebral angiograms cannot be performed MR angiograms (MRA), or CT angiograms can be done alternatively.

Electroencephalogram (EEG)

EEG monitors the brain’s electrical activity. EEG is used in diagnosing seizure disorders and metabolic, infectious, or inflammatory disorders. EEGs may be used to confirm brain death. This test can be performed in outpatient basis. A person being tested usually sleeps on a bed. A series of electrodes are attached to the scalp. The electrodes are attached to wires (also called leads) that carry the electrical signals of the brain to a machine. The procedure usually lasts for 30 – 60 minutes. Patients may be asked to open and close their eyes, change their breathing patterns. The changes in the brain activity is transmitted to an EEG machine or computer.

Nerve conduction studies (NCS)

A NCS measures the nerve’s ability to send signals (amplitude and speed). A set of recording electrodes is placed to the skin over the skin. Wires connect the electrodes to a machine. A small electrical pulse is given on the skin to stimulate the nerve. The electrical signal is viewed on the machine. The graph will tell us the condition of the nerves.