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

N/A

Base of skull through the vertex

Venous Phase

N/A

N/A

N/A

N/A

Delayed Phase

N/A

N/A

N/A

N/A

Scan Comments: Non-contrast images are performed when indicated prior to CTA. Using a dual energy protocol is useful if bone removal is warranted. All scans are performed using the ALARA principle. 3D post-processing is performed with this protocol.

 

Technical Parameters

Parameters

kVp

90/Sn150

Effective mAs

CareDose

Quality Reference mAs

180/138

Time (Rotation)

0.25 sec.

Average Acquisition Time

2-4 sec.

Collimation

128 x 0.6 mm

Pitch Value

0.7

Scan Direction

Caudocranial
Comments: Images are acquired using 90/150 kVp setting with a Sn filter. CareDose is used to reduce patient dose. A 0.25 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

Bv40 (3)

Br64 (3)

Qr40 (3)

Br54 (3)

Window Width and Level

350/50

2500/500

350/50

700/80

Reconstruction Comments: When generating mixed images, the DE composition is set to 0.6. MIP 360 degree spin and MIP 360 degree tumble reconstructions are also performed.

 

Reconstruction Parameters

Thin Data COW 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

Bv40 (3)

Br54 (3)

Br54 (3)

Br54 (3)

Window Width and Level

350/50

700/80

700/50

700/80

Reconstruction Comments: When generating mixed images, the DE composition is set to 0.6. MIP 360 degree spin and MIP 360 degree tumble reconstructions are also performed.

 

Contrast Parameters

Parameters

Contrast Type

Non-ionic

Contrast Volume

50 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 carotid arteries.