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High-resolution CT scan of the chest
Last reviewed: 06.07.2025
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Principles of High Resolution Computed Tomography (BPKT)
High-resolution computed tomography images are constructed using thin slices and a high spatial resolution slice reconstruction algorithm. Traditional CT scanners are also capable of producing thinner slices than the standard 5-8 mm. If necessary, the image formation parameters are changed by setting the slice thickness on the working console to 1-2 mm.
In spiral CT, slice thickness can also be adjusted after scanning, with a spiral pitch of 1:1. However, slices thinner than 1 mm are not informative because they significantly degrade image quality.
High-resolution computed tomography is not the method of choice for routine examination of the chest organs due to the significant increase in radiation dose. The increase in examination time and the high cost of printing a large number of sections on a printer are additional arguments against the widespread use of high-resolution computed tomography. Only structures with a high natural difference in density, such as bone and adjacent soft tissues, will be visualized significantly better.
Indications for the use of high-resolution computed tomography
One of the important advantages of high-resolution computed tomography is the ability to differentiate old cicatricial changes in tissues from acute inflammation, for example, in immunocompromised patients or in patients who have undergone a bone marrow transplant. Cicatricial changes always have clear boundaries, while the acute inflammatory process is surrounded by an edematous zone. High-resolution computed tomography is often the only method that determines the possibility of continuing chemotherapy in patients with lymphoma in the aplastic phase (chemotherapy is stopped when fungal pneumonia develops). Acute inflammatory infiltration can sometimes be found next to old cicatricial changes.
Because the slices are extremely thin, a horizontal interlobar fissure in the form of an irregular ring or crescent may appear on the scans.
Small areas of collapse of the lung tissue, which are usually adjacent to the posterior pleura, must be distinguished from planar sections of the interlobar fissures. In doubtful cases, repeated scanning with the patient in the prone position helps. In this case, the areas of collapse or hypoventilation will disappear or appear in front. If changes in the lung tissue persist, one should think about the presence of infiltration or pneumoconiosis.
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