Phase-Contrast MRI: Physics, Techniques, and Clinical Applications
| Autor: | William Burke, David Wymer, Kunal P. Patel, Vinay K. Bhatia |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Physics of magnetic resonance imaging
Signal-To-Noise Ratio Signal 030218 nuclear medicine & medical imaging 03 medical and health sciences 0302 clinical medicine Imaging Three-Dimensional Normal pressure hydrocephalus Aliasing medicine Humans Radiology Nuclear Medicine and imaging Brain Diseases Modality (human–computer interaction) medicine.diagnostic_test business.industry Physics medicine.disease Magnetic Resonance Imaging Stenosis Signal-to-noise ratio (imaging) Cardiovascular Diseases 030220 oncology & carcinogenesis Elasticity Imaging Techniques Elastography business Blood Flow Velocity Magnetic Resonance Angiography Biomedical engineering |
| Zdroj: | Radiographics : a review publication of the Radiological Society of North America, Inc. 40(1) |
| ISSN: | 1527-1323 |
| Popis: | With phase-contrast imaging, the MRI signal is used to visualize and quantify velocity. This imaging modality relies on phase data, which are intrinsic to all MRI signals. With use of bipolar gradients, degrees of phase shift are encoded and in turn correlated directly with the velocity of protons. The acquisition of diagnostic-quality images requires selection of the correct imaging plane to ensure accurate measurement and selection of the encoding velocity and thus prevent aliasing and achieve the highest signal-to-noise ratio. Multiple applications of phase-contrast imaging are actively used in clinical practice. One of the most common clinical uses is in cardiac valvular flow imaging, at which the data are used to assess the severity of valvular disease and quantify the shunt fraction. In neurologic imaging, phase-contrast imaging can be used to measure the flow of cerebrospinal fluid. This measurement can aid in the diagnosis and direct management of normal pressure hydrocephalus or be used to evaluate the severity of stenosis, such as that in Chiari I malformations. At vascular analysis, phase-contrast imaging can be used to visualize arterial and venous flow, and this application is used most commonly in the brain. Three-dimensional imaging can yield highly detailed flow data in a technique referred to as four-dimensional flow. A more recently identified application is in MR elastography. Shear waves created by using an impulse device can be velocity encoded, and this velocity is directly proportional to the stiffness of the organ, or the shear modulus. This imaging modality is most commonly used in the liver for evaluation of cirrhosis and steatosis, although research on the assessment of other organs is being performed. Phase-contrast imaging is an important tool in the arsenal of MRI examinations and has many applications. Proper use of phase-contrast imaging requires an understanding of the many practical and technical factors and unique physics principles underlying the technique.©RSNA, 2020. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|