CT scanner
A CAT scan or a CT scanner machine is a large machine in the shape of a doughnut. The patient is made to lie on a couch. The couch can slide backwards and forwards. The couch slips into the centre of the doughnut shaped machine which takes the x-ray images around the body. The actual procedure takes anywhere from half an hour to one and half hours. During the CAT scan procedure, the patient's bodily movement has to be minimal and should remain as still and quiet as possible. This significantly helps to increase the clarity of the x ray images.
Some CAT scans need special preparations before hand. The preparation may vary according to the type of scan taken.
- For abdominal CT scans, the patient is asked not to eat or drink anything after midnight, the night before the scan. A 'contrast medium' has to be drunk or an injection of 'contrast medium' is administered to the patient. Some of this liquid can be taken at home but more of the liquid is taken in the x ray department before the scan. The contrast medium makes the digestive system show more clearly in the scan. This does not have any side effects.
- For CT scans of the head, the patient is given an injection of 'contrast medium' dye beforehand to make the scan clearer.
- For CT scans of the chest, the injection of 'contrast medium' dye is administered beforehand to show up the tissues in the area containing cancer or blood vessels more clearly.
- For pelvic CT scans, the patient is asked not to eat or drink after midnight of the night before the scan. An injection of 'contrast medium' is given before the scan. An injection of a drug to slow down the movement of the pelvis area is given so that there will be distortion during the time of the scan.
- For a rectal scan, the patient is given an enema occasionally. This makes the outline of the bowel stand out more during the scan.
- In certain detailed scans of the bowel called virtual colonoscopy, the patient is asked not to eat or drink for 36 hours before the study and two doses of a strong laxative the day before the scan is advised.
Spiral CT Scan
CAT scan technology continues to evolve and promises better quality pictures and patients safety. Newer type of CT scans is known as Spiral or helical CT scan. It is called Spiral scan because the X-ray beam rotates around the patient during the scan in a spiral shape. This helps to give a continuous picture with no possible gaps between the 'slices' of the scan. The 'spiral' or 'helical' CAT scans provide more rapid and accurate visualization of the internal organs. They give more detailed pictures of the organs and tissues including blood vessels. The Spiral CT scans are faster than a normal CT scan. Many trauma centers have started using such scans for more rapid diagnose of internal injuries after serious body trauma.
Myelography
Myelography or myelogram is used to make a diagnosis of spinal canal and spinal cord disorders like nerve compression that in turn causes pain and weakness. A special dye is introduced into the spinal sac that in turn shows up in the x-ray to signify any deformities. The dye acts as an exclusive agent to outline the nerve roots and the spinal cord thus helping the doctor determine if there are any abnormal shapes in the spinal cord. Before CT scans and MRI scans were introduced, it was myelography that was used to study any abnormalities in the spinal cord. Current medical world uses myelography only for complicated revision spine surgeries and for patients who have metal plates or screws in their spine. Myelography is primarily used to identify slipped disk by exactly locating the disk or disks concerned. Spinal arthritis can develop bone spurs that may press against the nerves and cause pain, myelography can help identify if surgery is required and can also help spot if the spinal canal is narrowed. Tumors can be accurately located. A patient preparing for myelogram must stop a solid diet for a day and drink plenty of clear fluids.
Bibliography / Reference
|
