CT Angiographic Measurement of the Carotid Artery: Optimizing Visualization by Manipulating Window and Level Settings and Contrast Material Attenuation
| Autor: | Yi Liu, Kenneth D. Hopper, David T. Mauger, Kimberly A. Addis |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
medicine.medical_specialty
medicine.diagnostic_test Phantoms Imaging business.industry Iohexol Carotid arteries Attenuation Contrast Media Imaging phantom Transverse plane Carotid Arteries Maximum intensity projection Attenuation coefficient Angiography Medicine Carotid Stenosis Radiology Nuclear Medicine and imaging Radiology Tomography X-Ray Computed business Vascular Stenosis Biomedical engineering |
| Zdroj: | Radiology. 217:494-500 |
| ISSN: | 1527-1315 0033-8419 |
| DOI: | 10.1148/radiology.217.2.r00oc32494 |
| Popis: | To evaluate a broad range of window and level settings for various contrast material attenuation coefficients and degrees of vascular stenosis to obtain the most accurate computed tomographic (CT) angiographic measurements.A total of 25, 480 measurements were made transversely (perpendicular to the lumen) and by means of maximum intensity projection (MIP) in a phantom with stenoses of 0%-100%, contrast material with attenuation coefficients of 150-350 HU, and 14 window and 13 level settings. Edge definition was also evaluated.There was an inherent relationship between the contrast material attenuation coefficient and the optimal window and level settings in the measurement of stenoses at both transverse and MIP CT angiography. This relationship between the contrast material attenuation coefficient D: and the optimal settings for window W: and level L: was represented by the following simple equations: W:/D: = [-2 x (L:/D:)] + 1.3, where -0.2L:/D:0.5, and W:/D: = [3.3 x (L:/D:)] - 1.3, where 0.5L:/D:1.0. With a vascular contrast material attenuation coefficient of 250-350 HU, the best transverse and MIP display settings for the window and level were 96 and 150 HU, respectively.The use of optimized window and level settings at CT angiography reduces measurement variability. |
| Databáze: | OpenAIRE |
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