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Perfusion CT or CT Perfusion is a type of Perfusion Scanning using Computed Tomography.It is helpful in the evaluation of the vascularity of tissue in the body. In this, the temporal changes in tissue density are measured, providing information about the vascularity of the tissue.
Ventilation/perfusion scans, sometimes called a VQ (V=Ventilation, Q=perfusion) scan, is a way of identifying mismatched areas of blood and air supply to the lungs. It is primarily used to detect a pulmonary embolus. The perfusion part of the study uses a radioisotope tagged to the blood which shows where in the lungs the blood is perfusing.
CT Perfusion scan of the brain. CT perfusion imaging is a specific form of CT to assess flow through blood vessels whilst injecting a contrast agent. [21] Blood flow, blood transit time, and organ blood volume, can all be calculated with reasonable sensitivity and specificity. [21]
CT images of the head are used to investigate and diagnose brain injuries and other neurological conditions, as well as other conditions involving the skull or sinuses; it used to guide some brain surgery procedures as well. [2] CT scans expose the person getting them to ionizing radiation which has a risk of eventually causing cancer; some ...
The recommended procedure of ASL registration for voxel-wise analysis is to register the perfusion map to a gray matter segmentation of each individual in a non-rigid procedure. [citation needed] Gray matter often requires more oxygenation and is the source of more brain activity compared to white matter. Therefore, gray matter CBF is often ...
Such scans are most useful for tissues outside the brain, where location of tissues may be far more variable. For example, SPECT/CT may be used in sestamibi parathyroid scan applications, where the technique is useful in locating ectopic parathyroid adenomas which may not be in their usual locations in the thyroid gland. [14]
In conventional CT machines, an X-ray tube and detector are physically rotated behind a circular shroud (see the image above right). An alternative, short lived design, known as electron beam tomography (EBT), used electromagnetic deflection of an electron beam within a very large conical X-ray tube and a stationary array of detectors to achieve very high temporal resolution, for imaging of ...
The typical human adult's skull contains approximately 1500 grams of the brain (including gray matter and white matter), 100-130 milliliters of blood, and 75 milliliters of cerebrospinal fluid. About 15% of the blood volume is present in the arteries , 40% in the veins, and 45% in the nerve tissue and capillaries.