CT Scans

27th November 2006 at 12:01 GMT by Dr.C.A.Jenner MB BS, FRCA. Permalink.

Article on the role of CT scans in the investigation of painful conditions

Introduction

A Computed Tomography (CT) Scan is an X-ray technique that produces images of the internal organs, by rotating a thin X-ray beam around the body.

In a CT Scan, a special kind of X-ray is carried out to produce pictures of inside of the body. This is done by an X-ray generating device that rotates around the body and creates numerous cross-section images of the body, also known as ‘slices’, on the computer screen.

The images generated are black, white and grey and can be viewed in three dimensions.

Uses and Benefits

The CT Scan is one of the best tools for studying the chest and abdomen.

The fact that the CT imaging can show several types of tissue with great clarity makes it the most beneficial. The tissues concerned range from lung and bone to soft tissue and blood vessels.

Here we list some of the main purposes for which a CT Scan might be advised:

• Diagnose muscle and bone disorders, such as bone tumors and fractures
• Pinpoint the location of a tumor, infection or blood clot
• Guide procedures such as surgery, biopsy and radiation
• Detect and monitor diseases such as cancer or heart disease
• Detect internal injuries and internal bleeding

The most commonly studied areas of the body include:

• Chest (thorax)
• Abdomen
• Urinary tract
• Liver
• Pancreas
• Gallbladder and bile ducts
• Adrenal glands
• Spleen
• Arm, legs

The Procedure

A CT Scan can be used to make images of every part of the body, including the bones, nerves, muscles and organs.

Depending on the part of the body being examined, a dye may be used to make some tissues show more clearly. For scans of the abdomen, the patient might be asked to take a drink containing barium that shows up white on the scans. For other scans, contrast medium might be injected into the veins.

During a CT Scan, the patient is made to lie on a table that is hooked to the CT scanner, a large doughnut-shaped machine. The table is positioned so that the part of the body being examined lies within the ring. The table moves backward or forward to take each new image ‘slice’. The scanner rotates around the body as each picture is taken.

In some cases, a sedative is given to ensure that the patients are relaxed and comfortable during the procedure. The scan can take almost an hour to perform. However, in all at least two hours should be allowed for the whole visit.

Precautions

In some cases, certain precautions are also issued to patients before the CT Scan. Here we list a few main precautions that are usually advised:

• People having abdominal, pelvic or brain scans may be given special instructions about eating and drinking.
• Women having a pelvic scan may be asked to insert a tampon beforehand.
• Patients may also be advised to remove any metal objects they might be wearing, since some types of metals can interfere with the image quality. These objects include coins, jewelry and hair clips along with clothing including metal zips and buttons.
• Patients with asthma, allergies, diabetes, kidney problems and pregnant women are normally advised against a CT Scan.