Aortic and Internal Carotid Atherosclerosis in Patients with Carotid Stenosis: Semiautomatic Volumetric Analysis of Low-Attenuation Plaque on Curved Planar Reformations Using MDCT Angiographic Data

Figure 1

Semiautomatic volumetric data of ICA plaques with attenuation-dependent color codes in a 64-year-old man with an old cerebral infarction.

(a) MIP image of an ICA with a line running a target of area that is automated created after manual selections of starting and end-points (black arrows). The NASCET method estimates 50% internal carotid stenosis (white arrow)

(b) A straight CPR after a manual segmentation of the ICA from the proximal end (large arrow) to the distal end (large arrowhead) shows the possible normal interior contours (thin yellow lines) that were parallel to the outer wall contours. Small arrows indicate a stenosis due to large plaques, and small arrowhead indicates a small plaque in distal to the stenotic area

(c) A cross-section MPR image with predetermined attenuation ranges shows a plaque (arrow), 3 mm thick, and light and dark green codes (30-150 HU) with orange code (<30 HU) in the left anterior interior. A thin yellow circle indicates the possible normal interior contours that were parallel to the outer wall contour

(d) Volume-rendering image of an ICA, with color codes depending on CT attenuation, shows dense plaques with green codes and orange codes corresponding to the stenotic site (arrows) and the distal plaque (arrowheads) in Figure 1(c). Volume of each attenuation range inside of the lumen is demonstrated in the right lower corner. The volume of plaque with <30HU (LPV) is 33.6mm3, and that with <150 U (TUPV) is 436.3 mm3

(e) Volume-rendering image of the aortic arch with color codes depending on CT attenuation shows plaques with green codes and orange codes (arrows) in the left anterior wall. The volume of plaque with <30HU (LPV) is 150.6mm3 and that with <150 HU (TUPV) is 6134.2 mm3