Acquisition Phase	Phase Included	Scan Delay	Respiration Phase	Anatomical Coverage
Non Contrast	N/A	N/A	N/A	N/A
Arterial Phase	Yes	Bolus triggered	Inspiration	Aortic arch through Circle of Willis
Venous Phase	N/A	N/A	N/A	N/A
Delayed Phase	N/A	N/A	N/A	N/A
Scan Comments: If bone removal is necessary, a Dual Energy CTA Carotid protocol should be used to optimize post-processing. All scans are performed using the ALARA principle. 3D post-processing is performed with this protocol.

Technical Parameters	Parameters
kVp	100 / 140
Effective mAs	Use dose reduction software
Quality Reference mAs	270 / 270
Time (Rotation)	0.28 sec
Average Acquisition Time	5-7 sec
Collimation	128 x 0.6mm
Pitch Value	0.7
Scan Direction	Caudocranial
Comments: Images are acquired using 100/140 kVp setting with a Sn filter. Dose reduction software is used to reduce patient dose. A 0.28 rotation time is used to increase scan speed to avoid venous contamination.

Reconstruction Parameters	Soft Tissue Open Field	Bone Open Field	Thin Data Open Field	Hi Res Brain Only
Slice Thickness	3 mm	3 mm	0.75 mm	0.75 mm
Reconstruction Spacing	3 mm	3 mm	0.5 mm	0.5 mm
Reconstruction Algorithm	D30f	B70f	Q30f	B50f
Window Width and Level	350/50	2500/500	350/50	700/80
Reconstruction Comments: When generating mixed images, the DE composition is set to 0.8.

Reconstruction Parameters	Thin Data Carotid Mag	Sliding MIP True Axial (Brain Only)	Sliding MIP Coronal (Brain Only Aligned to Basilar Artery)	Sliding MIP Sagittal (Brain Only)
Slice Thickness	0.75 mm	16 mm	16 mm	16 mm
Reconstruction Spacing	0.5 mm	3 mm	3 mm	3 mm
Reconstruction Algorithm	I26f	B50f	B50f	B50f
Window Width and Level	350/50	700/80	700/80	700/80
Reconstruction Comments: When generating mixed images, the DE composition is set to 0.8.

Contrast Parameters	Parameters
Contrast Type	Non-ionic
Contrast Volume	60-100 mL
Saline Flush	N/A
Injection Rate	5-6 mL/sec
Oral Contrast	N/A
Contrast Volume	N/A
Comments: Bolus tracking is performed off the aortic arch using a 25 HU trigger setting.