Article Figures & Data
Figures
- Fig 1.
Schematic representation of the automatic algorithm to derive arteriograms (CTPa) from CT perfusion data described in Mendrik et al.9
- Fig 2.
Maximum intensity projections (20 mm) of 2 cases from the evaluation dataset in which the proximal arterial quality in the CTPa was considered equivalent to standard CTA by both observers. Left: Standard CT angiogram. Middle: CTP-derived angiogram showing both arteries and veins. Right: CTPa showing the arteries. Case 7: window = 870 HU, level = 340 HU. Case 21: window = 540 HU, level = 270 HU. Arrows indicate superimposed veins in CTA that are absent in CTPa.
- Fig 3.
Maximum intensity projections (30 mm; window, 780 HU; level, 400 HU) of case 2, which received low VAS scores for arterial quality in CTPa from both observers. The right medial cerebral artery is occluded; the small collateral arteries have a time-to-peak of the contrast enhancement curve similar to that of the veins and thus are not present in the CTP-derived arteriogram (arrow). On the CTP-derived angiogram, however, the collateral arteries are visible (arrow). The source of subarachnoid hemorrhage in this patient is thought to have been the earlier infarction that was caused by the right media occlusion.
- Fig 4.
Maximum intensity projection (20 mm) subimages of 4 different patients from the evaluation dataset with a window of 800 HU and a level of 350 HU. Two patients with subarachnoid blood (cases 11 and 20) and 2 with large aneurysms (cases 3 and 14) near the skull base, illustrating a clear arterial view due to the absence of bone, veins, and subarachnoid hemorrhage in CTPa. Top row: Standard CTA scans. Middle row: CTPa. Bottom row: Angiograms (showing both arteries and veins) derived from the CTP scans.
Tables
- Table 1:
Mean VAS scores of both observers, per arterial territory over 24 patients, for arterial visual quality in CTPa using standard CTA as a referencea
Mean VAS Score Observer 1 Mean VAS Score Observer 2 Proximal arteries ACA territory 94% 95% MCAb territories 93% 94% PCA territory 94% 95% More peripheral arteries ACA territory 87% 90% MCAb territories 81% 91% PCA territory 86% 91% - Table 2:
Mean VAS scores of both observers, per arterial territory over 24 patients, for the presence of superimposed bone and veins in CTPa using standard CTA as a referencea
No. of Cases with Superimposed Bone in Standard CTAb Presence of Superimposed Bone in CTPa No. of Cases with Superimposed Veins in Standard CTAc Presence of Superimposed Veins in CTPa Av Obs 1 Av Obs 2 Av Obs 1 Av Obs 2 Proximal area ACA territory 12 5 % 5 % 18 4 % 4 % MCAd territories 4 5 % 3 % 23 6 % 11 % PCA territory 23 3 % 3 % 24 4 % 9 % More peripheral area ACA territory 2 3 % 3 % 22 5 % 16 % MCAd territories 8 5 % 2 % 24 7 % 20 % PCA territory 0 – – 24 5 % 20 % -
Note:—Av indicates average; Obs, observer.
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↵a A 0% score indicates no presence of superimposed bone and veins in CTPa compared with the full presence in standard CTA.
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↵b Number of cases (of 24) in which bony structures hampered evaluation of arteries within the specific territory on standard CTA.
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↵c Number of cases (of 24) in which veins hampered evaluation of arteries within the specific territory on standard CTA.
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↵d Average over left and right sides.
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