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

Top of the head through the entire aortic vasculature

Venous Phase

N/A

N/A

N/A

N/A

Delayed Phase

N/A

N/A

N/A

N/A

Scan Comments: This protocol is used to evaluate the vasculature of patients with connective tissue disorders to r/o aneurysm, dissection or vascular anomaly. The protocol is often modified and limited to a specific area of interest. A flash spiral protocol is used to limit patient motion artifacts, specifically cardiac motion over the aortic root. Additionally, the fast scan times are important when the patient is short of breath or a limited volume of contrast is needed. All scans are performed using the ALARA principle. 3D post-processing is performed with this protocol.

 

Technical Parameters

Parameters

kVp

140

Effective mAs

140

Quality Reference mAs

N/A

Time (Rotation)

0.28 sec

Average Acquisition Time

4-6 sec

Collimation

128 x 0.6mm

Pitch Value

1.6

Scan Direction

Craniocaudal

Comments: A fixed mAs setting is used to limit noise and artifact, specifically in the brain. For large patients, 140 kVp may be necessary with a reduced effective mAs to maintain image quality. We prefer to keep the pitch lower (less than 2.5) when scanning through the abdomen. This will avoid increased image noise or spiral artifact while still minimizing both cardiac and breathing motion.

 

Reconstruction Parameters

Soft Tissue

Thin Data

Lung

Head

Slice Thickness

 3 mm

0.75 mm

3 mm

5 mm

Reconstruction Spacing

 3 mm

0.5 mm

3 mm

5 mm

Reconstruction Algorithm

B30f

B20f

B80f

I30f (3)

Window Width and Level

410/10

410/10

1600/-500

100/30

Reconstruction Comments: When using flash spiral mode, the DFOV is limited by the smaller of the two detector arrays to 33.2cm. This limitation can be overcome by reducing the pitch value to allow for a greater DFOV. Coronal and sagittal image reconstructions are also performed.

 

Reconstruction Parameters

Neck

Neck

Neck

Slice Thickness

 3 mm

3 mm

 0.75 mm

Reconstruction Spacing

 3 mm

3 mm

 0.5 mm

Reconstruction Algorithm

B30f

B70f

B20f

Window Width and Level

350/50

2500/500

350/50

Reconstruction Comments: When using flash spiral mode, the DFOV is limited by the smaller of the two detector arrays to 33.2cm. This limitation can be overcome by reducing the pitch value to allow for a greater DFOV. Coronal and sagittal image reconstructions are also performed.

 

Contrast Parameters

Parameters

Contrast Type

Non-ionic

Contrast Volume

80-120 mL

Saline Flush

N/A

Injection Rate

4-5 mL/sec

Oral Contrast

H2O

Contrast Volume

1000 mL

Comments: Bolus tracking is performed on the aortic arch using a 40 HU trigger setting.