CT Scan with Contrast

A CT scan is a technique that gives detailed images of the inside of the body. This is a painless procedure that combines the power of a sophisticated X-ray machine with a computer, to generate a 3D view of the inside of the body. This advanced method provides an easy way to inspect any organ of the body in much finer detail. In this procedure, the X-ray equipment rotates around the body and sends several beams to take multiple pictures of the same area from different angles, which are then put together by the computer to reveal an extremely detailed cross-sectional 3D image of the part of the body under examination. A normal X-ray machine uses only one radiation beam to produce an image that is not capable of giving a clear idea about the disease.

A CT scan is not the same as a MRI scan. This is because a MRI scan uses magnetic fields to generate pictures of inside the body as compared to the X-ray beams used in CT scans. Also, MRI scans are used only in a few situations, like diagnosing brain tumors and primary bone tumors. CT scans, on the other hand, still remains one of the best medical tests and tools for early detection of various diseases.

CT Scan Benefits
CT scans have been extremely useful to diagnose diseases and disorders in the early stages of development. Doctors find this procedure beneficial to detect tumors early, which in turn helps to plan the treatment to prevent further complications. CT scanning could determine whether an artery wall has swollen, as well as find out the severity of internal injuries.

Diagnosing any health problem early is the key to cure it, and this can be easily accomplished with the help of a CT scan. This is because a CT scan procedure is capable to quickly evaluate injuries of the heart, lungs and even blood vessels. CT scanning can also be used to know how the body is responding to treatments, like radiation therapy and chemotherapy. In order to diagnose diseases related to bones, such as osteoporosis, the bone mineral density needs to be ascertained, which can be effectively done using a CT scan.

CT Scan With Contrast
CT scanning that is done with the help of contrast agents can play a significant role to improve the images of the area to be examined. For a better visualization of a specific area within an organ, a CT scan with contrast is a good option. The contrast, also known as a dye, is basically a substance that is administered intravenously or taken orally during the CT scan test. These substances have the capability to weaken (attenuate) X-rays. When these substances are taken, they travel in the body and are absorbed by the organs. When the radiation beams pass through the organ containing the contrast, these X-rays attenuate significantly. As a result, the organs or the tissues that contain the contrast are highlighted, which appear as white areas on the final CT images.

This method that involves use of contrasting agents gives clearer images of the organ to be studied. For diagnosing tumors, and to know the exact location of the tumor, sometimes a CT scan with contrast is used. A blood clot deep into the venous system, or blood vessel defects can be easily detected with this procedure. This new innovative technique enhances particular structures of the organ which helps to identify the abnormalities in the organ. Patients undergoing this type of CT scan are instructed not to consume solid food for at least 4-6 hours before the test. However, the patient is allowed to drink clear liquids such as water, apple juice, tea or clear soda, prior to the CT scan.

Contrast Agents
During a CT scan, the patient may be advised to take a contrast (dye) so that resultant images of a specific part of the body have greater clarity. This may be essential to detect the presence of a foreign object, or to diagnose any minute defects in a specific organ. When the image of a specific body part is produced using a contrast agent, certain areas of the image are highlighted. In other words, a precise visualization of the specific area of the organ is achieved, which in turn helps to asses complications in the organ. Some of the most commonly used contrasts are barium, iodine, barium sulfate, and gastrografin. Contrasts are mainly administered in 4 different ways which are listed below:

• Intravenous (injected through a vein to highlight blood vessels and to get a clearer image of the structure of the organs such as the spine, liver, and the brain)
• Oral (taken by mouth for an abdomen CT scan)
• Rectal contrasts to highlight large intestines
• Inhalation

Administration of contrast agents by allowing the patient to inhale a gas, namely xenon, is an uncommon method and is followed when highly sharp images of the lungs or the brain are required. Also, this procedure is conducted at very few locations worldwide and only in rare cases.

CT Scan with Contrast: Chest
A chest CT scan using contrast gives detailed images taken at varying angles of the different parts of the chest. The contrast media is generally given intravenously. It is a non-invasive procedure that provides increased visibility of the structures of the chest that include the lungs, heart, and surrounding bones. This method gives precise images that help to determine the presence and extent of injury. Chest CT scanning with contrast gives an in-depth view of inside the chest. This multiple angled X-ray technique takes many sharp images of the chest.

People having chest pain or symptoms of lung disease or difficulty in breathing may require chest CT scans with contrast. The procedure helps to diagnose the root cause of the problem. It looks for abnormalities such as lung tumors, blood clots, or excess accumulation of fluid around the lungs. Even conditions like pneumonia and tuberculosis can be detected with this method. Patients advised to undergo chest CT scans need to wear loose-fitting clothing and remove items like jewelry and other metal objects as they may interfere with the working of the machine.

CT Scan with Contrast: Abdomen
In order to scan the abdomen and the large intestines, rectal CT contrasts are often administered using an enema. The most commonly used rectal contrast is gastrografin and barium sulfate, which helps to enhance the images of the large intestines as well the bladder, uterus (womb) in women, and other organs contained in the pelvis. When gastrografin as a contrast is used, gastrointestinal organs that are within the abdomen are highlighted clearly in the resultant image. Sometimes, gastrografin, available as a water based drink is consumed to about 1000cc or 1500cc 1-2 hours prior to CT scan to get the desired result. Pregnant women are advised to stay away from abdominal scans as exposing the fetus to several beams of radiation can cause health complications in the unborn child.

CT Scan with Contrast Side Effects
Although CT scan is considered to be a safe procedure, contrast materials that are either given orally or intravenously may give rise to few side effects. However, no serious health complications will occur unless the patient is allergic to the medicine. People with diabetes or pre-existing kidney diseases are recommended to avoid the CT scan with contrast test. In most cases, the side effects remain for a short duration only. Oral contrasts have a bitter taste that lasts for a few minutes. In general, the side effects that may occur by using this type of CT scan are listed below:

• Vomiting and nausea
• Chills
• Fatigue
• Sneezing
• Dizziness
• Constipation, in case of rectal contrasts
• Allergic reactions, such as swelling of the throat and difficulty in breathing

Generally, a blood test is performed on the patient prior to CT scanning involving use of contrast agents, to verify whether his kidneys are functioning properly. In case the patient is allergic to contrast agents, the doctor should be immediately informed so that he can take precautionary measures to prevent any adverse reactions.