Acquisition Phase

Phase Included

Scan Delay

Respiration Phase

Anatomical Coverage

Non Contrast

Yes

N/A

Inspiration

Aortic stent only

Arterial Phase

Yes

Bolus triggered

Inspiration

Entire aortic vasculature

Venous Phase

N/A

N/A

N/A

N/A

Delayed Phase

Yes

60 sec post-arterial phase imaging

Inspiration

Aortic stent only

Scan Comments: The Flash Spiral Aorta Stent Protocol is useful when aortic root pathology is a concern to eliminate cardiac motion. Additionally, the fast scan times are important when the patient is short of breath or a limited volume of contrast is needed. Non-contrast and delayed images are necessary when following up stent placement or to r/o endovascular leak. Alternatively, dual energy can be used to provide virtual non-contrast images. All scans are performed using the ALARA principle. 3D post-processing is performed with this protocol.

 

Technical Parameters

Parameters

kVp

120

Effective mAs

CareDose

Quality Reference mAs

200

Time (Rotation)

0.28 sec

Average Acquisition Time

2-3 sec

Collimation

128 x 0.6mm

Pitch Value

2.0

Scan Direction

Craniocaudal

Comments: CareDose is used to reduce patient dose. 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

Thin Data

Lung

Slice Thickness

 3 mm

0.75 mm

 0.75 mm

3 mm

Reconstruction Spacing

 3 mm

0.5 mm

 0.5 mm

3 mm

Reconstruction Algorithm

I40f (2)

I26f (2)

B20f

I70f (2)

Window Width and Level

410/10

410/10

410/10

1600/-500

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.

 

Reconstruction Parameters

Coronal

Sagittal

Slice Thickness

 3 mm

3 mm

Reconstruction Spacing

 3 mm

3 mm

Reconstruction Algorithm

I40f (2)

I40f (2)

Window Width and Level

410/10

410/10

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.

 

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 off the abdominal aorta using a 230 HU trigger setting.