Article Figures & Data
Figures
- Fig 1.
The AKA was identified according to the following stepwise approach: 1) detect the hairpin vessel; 2) assess the continuity of the vessel to the aorta mainly around the pedicle of the vertebral arch (white arrows) as definite (a), conceivable (b), equivocal (c), or undetectable; 3) check the washout from the early-to-late arterial phase (white arrowhead), because vessels that are more prominent in the late arterial phase are likely to be veins (black arrowhead); and 4) sum the scores. We defined positive identification of the AKA as a total score of ≥3.
- Fig 2.
The ROIs placed for measuring CT numbers are shown in a coronal image of the ASA (A), a sagittal image of the ASA (B), an axial image of the spinal cord (C), and a sagittal image of the vertebral bone cortex around the vertebral foramen at the AKA (white arrow) running level (D).
- Fig 3.
Box range shows the first and third quartiles; whisker range, from the 5th to 95th percentiles. Seventy-kilovolt CTA yields significantly lower SSDE (A) and dose-length product (B) than 120-kV CTA (P < .001 for both).
- Fig 4.
Distribution of the side and level of the CSA to the AKA is shown. Two cases in which the CSA and the AKA were supplied by the axillary artery were described as “other.”
- Fig 5.
Seventy-kilovolt CTA yielded significantly higher scores than 120-kV CTA. A, Continuity score, median 3 (interquartile range, 2–3) compared with 2 (interquartile range, 1–3), respectively. B, Total score, median 5 (interquartile range, 4–5), compared with 4 (interquartile range, 3–5), respectively (P < .05 for both).
- Fig 6.
A, Curved multiplanar reformatted image of a 77-year-old woman scanned with a 120-kV protocol shows definite continuity between the AKA and the segmental artery. B, Curved multiplanar reformatted image of a 68-year-old man scanned with a 70-kV protocol shows clearer visualization of the AKA and the segmental artery from the aorta. Window center and width were set at 200 and 800.
- Fig 7.
Seventy-kilovolt CTA yielded a significantly higher CT number (A) and SNRAorta (B) than 120-kV CTA (P < .001 for both analyses).
Tables
Variables 120-kV (n = 60) 70-kV (n = 60) P Value Age (yr) .81 Mean 69 69 Range 57.0–76.3 54.8–76.0 Sex .83 Male (No.) 44 45 Female (No.) 16 15 Mean body mass index (kg/m2) 23.7 ± 3.3 23.2 ± 3.6 .48 Aortic disorder .46 Aneurysm (No.) 35 31 Dissection (No.) 25 29 Variables 120-kV 70-kV P Value Detection of collateral pathway (No.) (%) 13 (21.7) 13 (21.7) 1.00 Detection of critical segmental artery (No.) (%) 50 (83.3) 54 (90.0) .28 Variables 120-kV 70-kV P Value Spinal cord CT number (HU) 39.4 ± 7.1 54.3 ± 11.6 <.001b SD (HU) 12.5 ± 3.4 13.7 ± 3.9 .059 Bone cortex around the vertebral foramen CT number (HU) 657.4 ± 134.0 1,106.1 ± 246.2 <.001b Anterior spinal artery CT number (HU) 78.7 ± 13.3 127.7 ± 30.0 <.001b CNRASA-Cord 3.4 ± 1.6 5.6 ± 2.5 <.001b CNRASA-Bone 50.3 ± 17.0 75.9 ± 30.5 <.001b
