[Flash] Chụp CT hộp sọ - Cranial CT scan - eduMedia

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Summary

The technique of Tomodensitometry (TDM) is often referred to as a “scanner” because of confusion between the process itself and the apparatus employed in that process. This imaging technique depends of the use of x-rays. It is particularly useful for observing the brain.
The x-ray beam is emitted by an x-ray tube and is then transformed by a detector into an electrical message that is sent to a computer.
The system emitter/detector is moved around the patient and computer analysis of received signals, from different angles, enables the creation of images in section.
Credits: département de neuro-radiologie - CHU Henri Mondor - France
Click and drag the cursor vertically alongside the head. A CT section of that part of the brain appears to the right.

Learning goals

To illustrate the images in section that the scanner makes possible.
To recognize the different parts of the cranial cavity

is also sometimes referred to as a CAT (Computed Axial Tomogrpahy) scan. Unlike a conventional projective x-ray exam, which employs a stationary source, the CT scan uses a moving x-ray source that rotates around the patient. The angle of incidence of the x-rays can be altered as necessary. . The x-rays can also be made to focus on different levels of the target area, producing images of thin sections of the structure. The data thus obtained is fed into a computer, which originally generated the images of each thin section in 2D. Software has since been developed that enables the computer to reconstruct 3D images from such data.

The versatility of and the enhanced imagery produced by such a scan makes it a very useful medical tool, though the high radiation exposure (compared to conventional projective x-ray examinations) puts limits on the frequency of its use.

A cranial CT scan is particularly useful for detection and location of strokes, whether these are caused by thrombosis (blocking of a blood vessel by an abnormal blood clot), embolism (migration of an abnormal clot to an area of the brain different from its place of origin) or hemorrhage (excessive bleeding resulting from a ruptured blood vessel). CT scanning can also detect brain tumors, but less effectively than some other types of scan can.

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