EEG

An electroencephalogram (EEG) is a test that detects electrical activity in your brain using small, metal discs (electrodes) attached to your scalp. Your brain cells communicate via electrical impulses and are active all the time, even when you're asleep. This activity shows up as wavy lines on an EEG recording. An EEG is one of the main diagnostic tests for epilepsy. An EEG can also play a role in diagnosing other brain disorders. An EEG can determine changes in brain activity that might be useful in diagnosing brain disorders, especially epilepsy or another seizure disorder. An EEG might also be helpful for diagnosing or treating the following disorders:

• Brain tumor
• Brain damage from head injury
• >Brain dysfunction that can have a variety of causes (encephalopathy)
• Inflammation of the brain (encephalitis)
• Stroke
• Sleep disorders

DSA brain and carotid

Digital subtraction angiography (DSA) is a fluoroscopy technique used in interventional radiology to clearly visualize blood vessels in a bony or dense soft tissue environment. Images are produced using contrast medium by subtracting a "pre-contrast image" or mask from subsequent images, once the contrast medium has been introduced into a structure. Hence the term "digital subtraction angiography". In traditional angiography, images are acquired by exposing an area of interest with time-controlled x-rays while injecting contrast medium into the blood vessels. The image obtained includes the blood vessels, together with all overlying and underlying structures. The images are useful for determining anatomical position and variations, but unhelpful for visualizing blood vessels accurately.

Plain X-rays

Plain X-rays are the simplest medical images created through X-radiation. Other tests that also use X-rays are more complicated and require the use of computers to generate a picture; for example, computed tomography: CT (see InsideRadiology: CT scan). Any image created using an X-ray is due to different X-radiation absorption by different structures or parts in the body. A dense structure, such as bone, absorbs a high percentage of the X-ray beam (which appears light grey on the image), whereas low-density structures, such as soft tissues, absorb a small percentage (which appears dark grey on the image). The body has many different structures of varying densities and this difference creates a picture or image

CT scan

A computed tomography (CT or CAT) scan allows doctors to see inside your body. It uses a combination of X-rays and a computer to create pictures of your organs, bones, and other tissues. It shows more detail than a regular X-ray. You can get a CT scan on any part of your body. The procedure doesn't take very long, and it's painless.
How Do CT Scans Work?
They use a narrow X-ray beam that circles around one part of your body. This provides a series of images from many different angles. A computer uses this information to create a cross-sectional picture. Like one piece in a loaf of bread, this two-dimensional (2D) scan shows a “slice” of the inside of your body. This process is repeated to produce a number of slices. The computer stacks these scans one on top of the other to create a detailed image of your organs, bones, or blood vessels. For example, a surgeon may use this type of scan to look at all sides of a tumor to prepare for an operation.

MRI scan

Magnetic resonance imaging (MRI) uses a large magnet and radio waves to look at organs and structures inside your body. Health care professionals use MRI scans to diagnose a variety of conditions, from torn ligaments to tumors. MRIs are very useful for examining the brain and spinal cord. During the scan, you lie on a table that slides inside a tunnel-shaped machine. Doing the scan can take a long time, and you must stay still. The scan is painless. The MRI machine makes a lot of noise. The technician may offer you earplugs. Before you get a scan, tell your doctor if you

• Are pregnant
• Have pieces of metal in your body. You might have metal in your body if you have a shrapnel or bullet injury or if you are a welder.
• Have metal or electronic devices in your body, such as a cardiac pacemaker or a metal artificial joint

Myelography

Myelography is an imaging examination that involves the introduction of a spinal needle into the spinal canal and the injection of contrast material in the space around the spinal cord and nerve roots (the subarachnoid space) using a real-time form of x-ray called fluoroscopy. An x-ray (radiograph) is a noninvasive medical test that helps physicians diagnose and treat medical conditions. Imaging with x-rays involves exposing a part of the body to a small dose of ionizing radiation to produce pictures of the inside of the body. X-rays are the oldest and most frequently used form of medical imaging. When the contrast material is injected into the subarachnoid space, the radiologist is able to view and evaluate the status of the spinal cord, the nerve roots and the meninges. The meninges are the membranes which surround and cover the spinal cord and nerve roots. Myelography provides a very detailed picture (myelogram) of the spinal cord, nerve roots, subarachnoid space and spinal column.

CSF analysis

Cerebrospinal fluid (CSF) is a clear, colorless liquid found in your brain and spinal cord. The brain and spinal cord make up your central nervous system. Your central nervous system controls and coordinates everything you do including, muscle movement, organ function, and even complex thinking and planning. CSF helps protect this system by acting like a cushion against sudden impact or injury to the brain or spinal cord. CSF also removes waste products from the brain and helps your central nervous system work properly. A CSF analysis is a group of tests that look at your cerebrospinal fluid to help diagnose diseases and conditions that affect the brain and spinal cord.