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Contrast CT, or contrast-enhanced computed tomography (CECT), is X-ray computed tomography (CT) using radiocontrast. Radiocontrasts for X-ray CT are generally iodine-based types . [ 1 ] This is useful to highlight structures such as blood vessels that otherwise would be difficult to delineate from their surroundings.
In contrast to neuroimaging, neuroradiology is qualitative (based on subjective impressions and extensive clinical training) but sometimes uses basic quantitative methods. Functional brain imaging techniques, such as functional magnetic resonance imaging , are common in neuroimaging but rarely used in neuroradiology. Neuroimaging falls into two ...
It includes bright high signal flow and a background that is visible. [1] The phase-contrast velocity image has greater sensitivity to CSF flow than the magnitude image, since the velocity image reflects the phase shifts of the protons. [5] There are two sets of phase-contrast images used in evaluating CSF flow.
Even in emergency situations, when a head injury is minor as determined by a physician's evaluation and based on established guidelines, CT of the head should be avoided for adults and delayed pending clinical observation in the emergency department for children. [3] Many people visit emergency departments for minor head injuries.
In contrast-enhanced imaging, high-atomic-number contrast agents with K absorption edges in the diagnostic energy range may be present in the body. K-edge energies are material specific, which means that the energy dependence of the photo-electric effect is no longer separable from the material properties, and an additional term can be added to Eq.
Contrast resolution or contrast-detail is an approach to describing the image quality in terms of both the image contrast and resolution. Contrast resolution is usually measured by generating a pattern from a test object that depicts how image contrast changes as the structures being imaged get smaller and closer together.
For example, it can be used in brain imaging to suppress cerebrospinal fluid (CSF) effects on the image, so as to bring out the periventricular hyperintense lesions, such as multiple sclerosis (MS) plaques. [1] It was invented by Graeme Bydder, Joseph Hajnal, and Ian Young in the early 1990s. [2]
Contrast-enhanced ultrasound is regarded as safe in adults, comparable to the safety of MRI contrast agents, and better than radiocontrast agents used in contrast CT scans. The more limited safety data in children suggests that such use is as safe as in the adult population. [2]