Article Figures & Data
Figures
- Fig 1.
Zoomed-in view of the ACA (of Macaca sylvanus) at the peak of arterial opacification. Nearly the entire course of the ACA, with a diameter <200 μm in the distal portions, is visualized because of the excellent resolution afforded by the digital flat panel technology.
- Fig 2.
Time-resolved MIP images through a sagittal slab of the brain parenchyma of a Macaca sylvanus showing arterial, parenchymal, and venous phases of circulation in this animal with a heart rate of approximately 150 bps.
- Fig 3.
Six sequential frames showing opacification of the arteries, parenchyma, and the veins of the brain in a Rattus norvegicus model. In the parenchymal phase, the contrast enhancement of the brain is only minimally above the baseline value because of the contrast resolution of the scanner.
- Fig 4.
Demonstration of subclavian steal phenomenon by using dynamic CTA in a NZW rabbit model. A, An early arterial phase MIP image shows opacification of the left subclavian, left vertebral, and left common carotid arteries. B, A late arterial phase image shows opacification of the right subclavian artery via retrograde flow (reverse flow) from the right vertebral artery. Note the chemical vasculitis induced in the RCCA from an intra-arterial injection of elastase, which was used to demonstrate endothelial injury in this artery before scanning. C, Contrast intensity (HU) vs time curve showing the temporal delay in peak enhancement of right subclavian artery (yellow) with respect to aorta (blue) and left subclavian artery (pink).
- Fig 5.
A, An axial section through a single phase of a 4D time-resolved image stack used for estimating brain perfusion. The arterial and venous inputs used for computation are marked. B, Arterial and venous time opacification curves. C and D, Axial and coronal CBV maps computed by using the Patlak model.
- Fig 6.
A, A frame from the arterial phase of a dynamic scan obtained on a rat with occlusion of the proximal right ICA (arrow). The right ICA was occluded via a filament inserted in the ECA and then advanced into the ICA. B and C, Time-attenuation curves of the brain parenchyma on the right (B) and left (C) side of the brain. The perfusion maps derived from this model were unable to demonstrate the transit time difference between the left and right side of the brain due to limitations of the temporal and contrast resolution of the fpVCT scanner.
- Fig 7.
Image showing aneurysm creation used in NZW rabbit models: 3D reconstructions of an aneurysm by using fpVCT (left) and MDCT (right). Despite the small size of this aneurysm, the anatomy of the aneurysm sac, including a small bleb (arrow), can be well visualized by using fpVCT. The surface anatomy is considerably smoothed, and no bleb is identified with MDCT.
Tables
- Table 1:
Variation in heart rates of animals used for validating the temporal resolution of fpVCT in vascular pathology models
Animal Heart Rate (bpm) No. Macaca sylvanus 100 2 NZW rabbit 150 17 Rattus norvegicus 300–400 3 Mus musculus 500–600 13 - Table 2:
Different animals used for each dynamic study protocol and time-dependent vascular models created in each animal
Dynamic Study Animal No. Model Phases of blood flow Macaca sylvanus 2 Healthy control NZW rabbit 10 Healthy control Mus musculus 10 Healthy control Aneurysm filling NZW rabbit 10 Modified elastase aneurysm model Tumor blood flow NZW rabbit 4 VX2 tumor model Time-dependent pathologies NZW rabbit 1 Subclavian steal model Neuroperfusion (CBV, CBF, MTT) NZW rabbit 2 Stroke model Rattus norvegicus 3 ECA ICA filament Mus musculus 3 ECA ICA filament - Table 3:
CT acquisition settings used for static and dynamic scanning protocol for each animal
Animal Tube Voltage(kV[peak]) Tube Current(mAs) Gantry Rotation Time (sec) Total CE Scanning Time (sec) Macaca sylvanus 100 50 5 70–80 NZW rabbit 120 50 5 45 Rattus norvegicus 100 30 5 60 Mus musculus 100 30 5 55–60 - Table 4:
Results of each dynamic process and animal model comparing the time measured using 30-fps projection acquisition and visualization in dynamic 4D datasets after image reconstruction
Dynamic Process Being Monitored Anatomic Location and Flow Pattern Actual Time from Projection Data, 30 fps (sec) Animal Model Visualization in Dynamic 4D Datasets (gantry rotation time = 5 sec) Cerebral circulation Common carotid artery to internal jugular vein 15 Macaca sylvanus Yes Cerebral circulation Common carotid artery to internal jugular vein 12.3–13.3 NZW rabbit Yes SSS model Anomalous circulation 5–7.5 NZW rabbit Yes Pulmonary circulation IVC to aorta, 5.3 NZW rabbit Yes right heart to left heart, 3 NZW rabbit Yes tail vein to heart, 2–3 Mus musculus Yes heart to abdominal aorta, 2–3 Mus musculus Yes IVC to right heart 2.3 NZW rabbit Yes Pulmonary circulation Right heart to left heart, <2 Mus musculus No left heart to common carotid artery, 1.33 NZW rabbit No tail vein to IVC, <1 Mus musculus No IVC to right heart, <1 Mus musculus No left heart chamber to aorta <1 Mus musculus No
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