What is CT Scan?
Computer tomography scanning (CT Scan) is the computerised version of X-ray scans wherein radiations are used to decipher the shape and structure of internal organs of the patient’s body. The multiple X-ray reports are juxtaposed using computer software that ultimately puts together the overall image of the target organ(s).
Why is CT Scan performed?
CT scans are performed to get a detailed picture of the internal body anatomy, especially when there is a doubt of patient having suffered internal damage in a certain body part. CT scans help in diagnosis of such damage.
Types of CT Scan?
There are many types of CT scan known in the medical industry. They are differentiated from each other on the basis of the target organ or body part being studied in the scan. In addition to complete CT scan, the following different types of CT scan are found in hospitals:
- Pelvic CT Scan: Lower part of the abdomen and waist
- Thoracic CT Scan: Chest area scan
- Extremities: Limbs and shoulder scans
- Cranial CT Scan: Head region scan
- Abdominal CT Scan: Full abdomen scan
In terms of technology, there are two types of CT scan used in hospitals today. They are as follows:
Conventional CT Scan
This is the conventional method of applying X rays to computerised imaging in which slice by slice scans are taken and the machine stops the scan and moves to the next slice in a sequential step by step fashion. For each time that the scan stops a few seconds time is wasted. As a result, for a scan from the top of the abdomen to the pelvis, the patient has to hold his breath for a longer duration of time.
Spiral or Helical CT Scan
This is a more advanced form of CT scans in which the scans are taken in an organised and sequential manner without any stops in between. The scanner moves around the target body part in a spiral or helical manner and the scanning and imaging is completed simultaneously. There is no extra time wasted in frame shifts. Therefore, this type of CT scan is much faster and more comfortable for the patient.
In addition to the above types, CT scan can also be differentiated into computerised axial tomography (CAT), computerised coronal tomography (CCT), or computerised sagittal tomography (CST), depending upon the plane of imaging. Axial plane happens to be the most common plane of imaging used in scans and therefore, CAT scans are found prescribed commonly.
Preparation for CT Scan?
CT scans are often combined with contrast agent use. This helps the scanner to detect the organs, tissues and internal structures in a better fashion. Intravenous or oral administering of the contrast agent is common in the CT scan preparations. The patient is required to change into a gown or loose fitting clothing and may be asked to lie down or stand in the X-ray room during the scan.
Since the scan is done using ionized radiation, no other person other than the patient is allowed in the room at the time of the scan. The patient must notify the radiologist about his/her medications and sugar conditions that may require the patient to attend to sudden nature calls in between the long durations of the scan. Since the patient has to hold his breath several times during the scan, he/she has to practice beforehand. Taking in a few breathing exercises to increase stamina for the scan will help the generation of non-blurred images.
What happens during a CT Scan?
During a CT scan the patient is asked to lie down on a scan table that enters into the cylindrical shaped scanner machine. CT scanning machines house the X-ray emitter which releases ionized radiation on the target body part placed at the centre of the scanner. The patient is required to stay very still and hold his breath repeatedly to avoid blurring of images.
The ionised radiation passes through the patient’s body and is collected using multiple detectors as the X-rays leave the body. Images of the internal structure are created using images created by these deflection detectors. Hundreds of images are clicked in a CT scan out of which computerised tomography creates a three-dimensional or a two-dimensional image of the entire organ that is finally released in the report. After the scan is complete the patient can change and leave.
How long does CT Scan take?
The CT scan can take any amount of time between five minutes to forty minutes. This depends upon the number of scans required and level of scanning used. The patient is usually notified before the scan regarding the time that will be required in his case.
What happens after the CT Scan?
The CT scan is a non-invasive process and leaves no side-effects on the patient being scanned. The patient can resume his/her normal activities after the CT scan is done. The dye used in the scan will not be seen in urine or blood after the scan.
What are the possible risks of CT Scan?
There are hardly any risks of undergoing a CT scan. The technology is sound and well maintained and while the cylindrical enclosure is intimidating to many, the fact that it is open on both ends leaves no chance for claustrophobia. The contrast agent is not known to cause allergic reactions. However, in rare cases, the hypersensitivity can be treated.
Cost of CT Scan?
CT scans are growing in demand and therefore have been made available at various health centres and hospitals. The cost of a CT scan in India may range from Rs. 4000 to Rs. 6000.
The alternative names for CT scan are Lung imaging test (chest CT scans), CAT scans (axial plane), and Helical CT scans.