![]() ![]() As we’re made mostly of fat and water, there’s plenty of hydrogen to detect. Excited hydrogen ions emit signals toward the MRI scanner which, based on the intensity of the signal, creates a gray-scale image. MRIis an imaging modality that, besides anatomy, can also show physiological processes in the body (functional MRI - fMRI). MRI works by using magnetic fields and radiofrequency pulses to excite protons (hydrogen ions) in our body. Furthermore, CT imaging can be combined with radiological contrasts which act as visualisation aids. CT machines can also switch between the “bone window” and “soft tissue window”, depending on which structures we want to observe. These techniques offer variations in the “slice” thickness and the radiation dose used to create the image. There are many CT techniques, such as single slice CT (SSCT), spiral CT and multi slice CT (MSCT). The advantages of CT over x-ray radiography are that it enables a three-dimensional insight into the body, giving a more accurate presentation of the area of interest. If the density is altered, we express that by using basic CT terminology hyperdense, hypodense or isodense when compared to some other structure. Every tissue in the body has its normal density familiar to radiologists. Density is expressed in Hounsfield unit (HUs), which spans from +1000 for bones (bright), 0 for water (gray), to -1000 for air (dark). ![]() As CT uses x-rays, the image also depends on tissue density. This gives us a cross-sectional slice of the specific body region. It rotates around a stationary person creating multiple cross-sectional images, which can then be rendered into a 3D image. CT works by using x-rays too but the machine is more advanced. Radiography is most often used in chest x-rays (cxr), abdominal and skeletal x-rays.Īntrum of Highmore, Maxillary paranasal sinusĬomputed tomography (CT), earlier referred to as computed axial tomography (CAT), is another non-invasive imaging procedure. X-ray continues to be a highly utilized medical imaging modality as it offers high spatial resolution and enables comprehensive visualization of structures which can be hard to perceive in axial (cross sectional) perspectives.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |