TY - JOUR
T1 - CT angiographic measurement of the carotid artery
T2 - Optimizing visualization by manipulating window and level settings and contrast material attenuation
AU - Liu, Y.
AU - Hopper, K. D.
AU - Mauger, D. T.
AU - Addis, K. A.
PY - 2000
Y1 - 2000
N2 - PURPOSE: 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. MATERIALS AND METHODS: 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. RESULTS: 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 -0.2 < L/D < 0.5, and W/D = [3.3 x (L/D)] - 1.3, where 0.5 < L/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. CONCLUSION: The use of optimized window and level settings at CT angiography reduces measurement variability.
AB - PURPOSE: 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. MATERIALS AND METHODS: 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. RESULTS: 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 -0.2 < L/D < 0.5, and W/D = [3.3 x (L/D)] - 1.3, where 0.5 < L/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. CONCLUSION: The use of optimized window and level settings at CT angiography reduces measurement variability.
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U2 - 10.1148/radiology.217.2.r00oc32494
DO - 10.1148/radiology.217.2.r00oc32494
M3 - Article
C2 - 11058651
AN - SCOPUS:0033752855
SN - 0033-8419
VL - 217
SP - 494
EP - 500
JO - Radiology
JF - Radiology
IS - 2
ER -