Figure 1 | Scientific Reports

Figure 1

From: Assessments of arterial and venous phase radiodensity does not improve carotid near-occlusion diagnostics

Figure 1

The 12 measurement points in biphasic CTA exams. Case with right-sided near-occlusion without full collapse. 7 s between arterial and venous phase. ROIs placed to avoid the fuzzy edge around the artery. (A) Sagittal view with cervical levels (proximal and distal) marked with red dotted lines. Note that the proximal measurement still refers to the artery beyond (distal to) the stenosis (black arrowheads). (B) Arterial phase, proximal level. 488, 542 and 535 HU in right ICA (white arrow), left ICA (black arrow) and vertebral (white arrowhead). (C) Venous phase, proximal level. 351, 274 and 332 HU. Note the filling of the right jugular vein (black star with white rim). (D) Distal level, arterial phase. 486, 521 and 477 HU. Note the non-intuitive change in vertebral HU between proximal and distal phase that shifts the direction of v-correction from − 47 to + 9 HU whereas c-correction is more intuitive (− 54 and − 38 HU). (E) Distal level, venous phase. 379, 343 and 386 HU.

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