The spectrum of applications of computed tomography is diverse. Bones can be visualized particularly well, which is why CT is excellent for diagnosing bone fractures, signs of wear and tear, osteoporosis (CT bone densitometry) or a slipped disc. But tumors, bleeding, accumulations of water, cysts, abscesses and inflammations are also easy to see. But what exactly is examined?
CT: What is examined?
Examined are:
- Skull (CCT = cranial computed tomography).
- Neck and shoulder region
- Chest area and lungs
- Abdominal cavity
- Pelvis
- Spine
- Peripheral bones and joints
Vessels (CT angiography) can be well visualized if contrast agent is given by mouth or syringe beforehand. This is used, for example, as perfusion CT in the early diagnosis of strokes or in the imaging of coronary vessels. In the latter, the extent of arteriosclerosis can also be determined (coronary calcium measurement).
Computed tomography is also used – in addition to sonography – to take tissue samples under visual control (for example, from the liver) and to withdraw fluid accumulations (CT-guided biopsies) or to inject anesthetics in a targeted manner (for example, in cases of severe bone pain).
Virtual colonoscopy for early detection of colorectal cancer
Virtual colonoscopy, a CT scan that simulates a journey through the colon with an endoscope, can be used for early detection of intestinal disease and to clarify abdominal complaints. However, the extent to which it is equal or even superior to conventional colonoscopy is still under discussion.
The disadvantage is that no tissue samples can be taken; the advantage is that surrounding structures can also be assessed in the same examination procedure. By many patients, the carbon dioxide gas introduced through the anus in the process to unfold the bowel is perceived as unpleasant; however, an inserted tube is not exactly pleasant either.
What is the procedure for computed tomography?
The machine is located in a separate examination room. The patient lies flat on a couch and is pushed with it into the opening in the center. The couch moves slowly forward during the examination. The patient should lie as relaxed and quiet as possible.
He has contact with the treating staff via an intercom system and, if necessary, receives instructions, for example, to hold his breath briefly. The duration of the examination depends on the area examined and the type of procedure.
How long does a computed tomography scan take?
In most cases, the duration of a CT scan is between 10 and 30 minutes. Sometimes preparations are necessary – for example, the patient must not eat anything flatulent before examinations of the gastrointestinal tract. Contrast material is usually administered one to two hours beforehand.
CT: What are the advantages and disadvantages?
The actual CT scan is painless. However, the disadvantage is that the radiation exposure is higher than with conventional X-rays. Depending on the extent of the area scanned, the type of tissue, and the thickness of the slice images, it can be several times the natural annual radiation dose. However, the advantages outweigh the disadvantages – provided responsible and targeted use and avoidance of duplicate examinations.
