CT Angiographic Analysis of Carotid Artery Stenosis: Comparison of Manual Assessment, Semiautomatic Vessel Analysis, and Digital Subtraction Angiography
H.M. Silvennoinena,
S. Ikonena,
L. Soinnea,
M. Railoa and
L. Valannea
a From the Helsinki Medical Imaging Center, University of Helsinki, Helsinki University Central Hospital, Department of Radiology, Helsinki, Finland
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Fig 1. Measurement of the internal carotid artery stenosis in CTA axial images according to NASCET.
A, Maximal stenosis in left ICA.
B, Normalized vessel diameter. The reference point was chosen so that diameters are the same over a distance.
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Fig 2. A, Stenosis measurement levels marked to CTA MIP images according to NASCET. Dental filling artifacts are shown.
B, Vessel analysis method in determination of the grade of stenosis. Dental filling artifacts are shown.
C, DSA image.
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Fig 3. Scatterplot of degrees of stenosis in CTA (A) versus DSA (B) with regression line and 95% confidence intervals.
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Fig 5. Poststenotic collapse. A, Maximal stenosis in left ICA (big arrow). Calcification behind the open lumen. The right ICA is normal (small arrow).
B, The distal left ICA (big arrow) remains collapsed. Normal right ICA (small arrow).
C, MIP image of the left ICA.
D, DSA image of the left ICA.
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Fig 6. Underestimation of stenosis in DSA. A, An axial MIP image from the left ICA stenosis graded severe by CTA (arrow). According to the vessel analysis method (B, C) the stenosis is 77%. In DSA, the maximum stenosis is 50% (D). In surgery, the stenosis turned out to be severe.
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