CT stands for Computed Tomography, also known as a CAT (Computerized Axial Tomography). It is a diagnostic test that uses a combination of X-rays and advanced computer technology to create cross sectional anatomical images from different angles around the body. A computer puts these images together, and can make them into 2D and 3D images.
A CT scan is painless, fast and simple, gives physicians a non-invasive way to see inside your body. It using low amounts of radiation to generate highly detailed images of bones, muscles, fat, blood vessels and organs in a very short time and helps physicians diagnose many conditions that may not be diagnosed easily with other imaging methods like the X-ray or ultrasound.
We use a new 16-slice GE Brivo 385 CT Scanner at SCH. This multi-slice scanner offers considerable advantages to our patients as it allows for more comfortable exam, reduced waiting time, and a more accurate diagnosis than previous generation CT units.
Specialized types of CT, called CTA or CT-angiography, are used to obtain high-resolution imaging of arteries. CTA examinations are frequently used to identify blood clots in the arteries to the lungs, as well as areas of narrowing and aneurysms in the blood vessels around the brain, and involving arteries in the abdomen and supplying the lower limbs or legs.
How does a CT scanner work?
The CT scanner is a large, square-shaped machine with a hole in the center, outfitted with a ring (called a gantry) that has beam opposite matching detectors. You lie still on a table that can move up and down, and slide into and out of the center hole. The gantry rapidly rotates around your body in a circular fashion as you lie still on a table. The table gently moves you through a scanner. In fractions of a second, the detectors relay data back to a computer, which assembles the information to create two- and three-dimensional, cross-sectional images of your body.
Before the exam
You will be given your arrival time and preparation instructions when you register for a CT scan. In most cases, you will be asked several questions prior to your scan. Be sure to inform your physician or technologist if you have any allergies from medicine or believe you are pregnant.
Depending on the exam ordered by your physician, you may be required to take an oral contrast.
The CT scanning usually takes 10 to 20 minutes.
During the exam
If you are having a body scan you will be required to change into a hospital gown.
The technologist will assist you on to the examination table. Straps may be used to help maintain the correct position and to hold still during the exam.
During the scanning, you will have to lie very still on scanning table. The table will move slowly through the machine as the actual CT scanning is performed. The technologist will monitor you through a window, communicate with you through an intercom and give you instructions on when to hold your breath.
If a contrast material is used, it will be injected through an intravenous line (IV) into an arm vein during the procedure.
For some tests, contrasts may be given in the rectum (if the radiologist recommends it).
After the exam
When the examination is completed, you will be asked to wait until the technologist determines that the images are of high enough quality for the radiologist to read.
After your CT scan is completed, you may resume all of your normal activities.
If a contrast given, you will be asked to drink six to eight glasses of water after your exam to help quickly flush the contrast from your body and so you do not become dehydrated.
If you are on dialysis and you receive an IV contrast, you will need to have dialysis within 24 hours of your CT test.
A radiologist will analyze the images and prepare reports which you can collect from the radiology department after 24 hours.
What is a contrast examination?
Depending on the exam, a solution called a “contrast” may be administered with an IV. Contrast is a liquid solution that improves visibility of specific areas of the body, such as blood vessels or the digestive tract. When the contrast is injected, it is common to feel warm and flush for one minute. If you have any allergy to iodine, please let your doctor and CT technologist know before having the CT scan.
How safe is a CT examination?
The CT is a safe and effective diagnostic procedure. Like many other imaging technologies, our latest GE Healthcare system (CT Brivo385) have been designed to include dose-reduction features, minimizing your exposure to radiation.
Is any preparation needed for a CT Scan?
For a plain study CT scan no preparation is needed.
For a contrast CT scan we will ask you to fast for four to eight hours prior and undergo a lab test Serum Creatinine report. This Lab test serum Creatinine report checks your kidney function. We need to know your kidneys are working properly before we inject a contrast solution.
For a CT scan of the abdomen or pelvis, patient may be required to drink the contrast as it helps to highlight the stomach and intestines on the images.
Previous reactions to IV contrast may require pre-medication prior to the CT exam.
If you take Glucophage (Metformin), you may take the medicine before the examination but do not take it on the day and 48 hours after the study is completed.
Can I have CT imaging if I am pregnant?
Pregnant woman should NOT have a CT exam, especially if the woman is in her first trimester (first three-month period of the pregnancy). Depending on the condition, there may be other exams available, such as an ultrasound, to help diagnose a medical condition. However, in special circumstances we can do the exam with the consent of the referring physician after taking the necessary safety precautions.
Can I breastfeed after an injection of CT contrast?
Typically, patients are instructed to wait for 48 hours after receiving the CT contrast injection before breastfeeding again.
LIST OF EXAMINATION (CT SCAN)
CT SCAN BRAIN (PLAIN/CONTRAST)
CT SCAN PNS (PLAIN/CONTRAST)
CT SCAN NECK (PLAIN/CONTRAST)
CT SCAN TEMPORAL BONE / MASTOID / IAC (PLAIN/CONTRAST)
CT SCAN PITUITARY FOSSA (PLAIN/CONTRAST)
CT SCAN ORBITS (PLAIN/CONTRAST)
CT SCAN FACIO MAXILLARY REGION (PLAIN/CONTRAST)
CT SCAN CHEST (PLAIN/CONTRAST)
CT SCAN CHEST (HRCT)
CT SCAN (PLAIN/CONTRAST)
CT SCAN SPINE (PLAIN/CONTRAST)
CT SCAN UPPER ABDOMEN (PLAIN/CONTRAST)
CT SCAN WHOLE ABDOMEN (PLAIN/CONTRAST)
CT SCAN PYELOGRAM (KUB) (PLAIN/CONTRAST)
CT SCAN SCANOGRAM (PLAIN)
CT SCAN MYELOGRAM (PLAIN/CONTRAST)
CT SCAN FISTULOGRAM / SINOGRAM (PLAIN/CONTRAST)
CT SCAN FACT (PLAIN)
CT SCAN BONES / JOINTS (PLAIN/CONTRAST)
3D RECONSTRUCTION (PLAIN)
LIST OF EXAMINATION (CT ANGIOGRAPHY)
CT PULMONARY ANGIOGRAPHY
CT CEREBRAL ANGIOGRAPHY
CT CAROTID ANGIOGRAPHY
CT RENAL ANGIOGRAPHY
CT PERIPHERAL ANGIOGRAPHY
CT ABDOMINAL ANGIOGRAPHY
The study your doctor has requested requires the injection of contrast material into a vein. The injection will be performed using standard sterile technique. The contrast provides improved visualization of certain tissues in the body. The contrast contains iodine. We use a form of contrast (non-ionic) that reduces the risk of minor adverse reactions.
During the injection you may feel a warm sensation and a metallic taste in the mouth. You may experience nausea for a few minutes. A mild allergic reaction may occur in the form of coughing, sneezing, skin rash and itching. Severe reactions are rare but may occur. These include difficulty breathing, swelling of the throat, diffuse swelling, seizure, drop in blood pressure, anaphylactic shock, kidney failure and cardiac arrest.
As with all types of intravenous injections, it is possible for the needle to slip out of the vein. If this occurs, contrast material is injected into the soft tissue of the arm (extra vacation). This results in swelling or pain at the injection site. Because we use non-ionic contrast, this is unlikely to cause tissue damage or permanent injury.
Patients who are at higher risk for adverse effects of contrast are those who:
- Have had a previous reaction to contrast material which required treatment.
- Have asthma or severe allergies
- Have severe or incapacitating heart disease
- Have multiple myeloma, sickle cell disease or polycythemia
- Have kidney disease, particularly if caused by diabetes
- Take certain oral diabetic medications.
We would like to emphasize that serious reactions to contrast are rare. The benefit of this exam is to assist your physician with making a diagnosis. There may be other imaging alternatives, however, your physician believes the CT Scan with contrast is the best diagnostic test for you after evaluating your symptoms and medical condition.
MBBS, FCPS, FVIR,
Fellowship in Diagnostic Radiology,
College of Physicians & Surgeons Pakistan,
Fellowship in Vascular Interventional Radiology
Monday to Saturday
10am to 5pm
Nasir / Salman
(+92)213 529 2707