Computed tomography of the thorax/chest (synonyms: thoracic CT; CT thorax) refers to a radiological examination procedure in which the thorax with its organs (esp. lungs) is examined using computed tomography (CT).
Indications (areas of application)
- Inflammatory changes of the breast organs
- Malformations in the area of the thorax (chest).
- Interstitial lung disease (parenchymal lung disease) – caused by damage to the cells surrounding the alveoli (air sacs), resulting in extensive inflammation and fibrotic scarring of the lungs
- Bone changes, such as metastases (daughter tumors).
- Pulmonary embolism – acute occlusion of one or more pulmonary vessels.
- Pulmonary malformation
- Lymph node
- Cystic fibrosis (synonyms: CF (fibrosis cystica); Clarke-Hadfield syndrome (cystic fibrosis); cystic fibrosis (CF))
- Therapy-resistant pneumonia (pneumonia).
- Trachea and bronchus stenosis
- Tumors in the thoracic region (cervical; mediastinal; pulmonary; pleural) – e.g., bronchial carcinoma (lung cancer) or esophageal carcinoma (esophageal cancer)
- Changes in blood vessels such as atherosclerosis (arteriosclerosis, arteriosclerosis), aneurysm formation.
- Changes in the heart as in heart failure (cardiac insufficiency).
The procedure
Computed tomography is one of the non-invasive, that is, not penetrating into the body, imaging X-ray diagnostic procedures. The body or the body part to be examined is imaged layer by layer with a rapidly rotating X-ray tube. A computer measures the attenuation of the X-rays as they pass through the body and uses this to determine a detailed image of the part of the body being examined.The principle of CT (computed tomography) is to show the differences in density of different tissues. For example, water has a different density than air or bone, which is expressed in different shades of gray. For even better differentiation of the tissue types, the patient can also be administered a contrast medium. This is contrast medium containing iodine. Healthy tissue absorbs contrast medium at a different rate than diseased tissue such as cancer. With the most modern equipment, the examination takes only a few minutes, i.e. the scanning process only a few seconds, so that the patient can hold his breath during the examination and movement artifacts are impossible.The examination is performed in a lying position. The latest devices use the multislice method, i.e. several slices are taken at the same time. Modern examination devices use a 64-slice method, i.e. 64 slices are taken at the same time. This method can be compared to a Rettig, which is cut in a spiral shape. Modern devices also work with a so-called low-dose technique, i.e. only 50% of the radiation is required to produce these precise images with a layer thickness of up to 0.4 mm. New reconstruction algorithms (reconstruction calculation methods) make this precision possible. Chest CT is performed in the supine position. Computed tomography of the thorax and its organs is now routinely used for many indications, as it is a rapid and very informative diagnostic procedure. Further notes
- The size determination of a lung tumor should be calculated from axial CT images determined mean length and width of the tumor (= 3-D reconstruction of CT data sets), because diameter determination is too inaccurate. In one study it was shown that compared to volumetry, diameter determination leads to a significant overestimation of tumor volume.
