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

Lung apices through the diaphragm

Venous Phase

N/A

N/A

N/A

N/A

Delayed Phase

N/A

N/A

N/A

N/A

Scan Comments: The flash spiral mode is most successful when imaging patients with heart rates 60-70 bpm. Utilizing this mode will result in extremely low dose exams. All scans are performed using the ALARA principle. 3D post-processing is performed with this protocol.

 

Technical Parameters

Parameters

kVp

Care kV (ref. kV 120)

Effective mAs

CareDose

Quality Reference mAs

240

Time (Rotation)

0.28 sec.

Average Acquisition Time

1-2 sec.

Collimation

128 x 0.6 mm

Pitch Value

3.2

Scan Direction

Craniocaudal

Comments:Using the flash spiral mode allows for greatest dose savings potential. The entire data series is collected in one heart beat thus avoiding the need for a slow pitch with multiple images across the R-R interval of the ECG wave. 100 kVp is used for most average size patients. ECG dose modulation is not necessary for this protocol. CareDose is used to reduce patient dose.

 

Reconstruction Parameters

Thin Data Heart Mag

Soft Tissue Open Field

Thin Data Open Field

Lung Open Field

Slice Thickness

 0.75 mm

3 mm

 0.75 mm

3 mm

Reconstruction Spacing

 0.5 mm

3 mm

 0.5 mm

3 mm

Reconstruction Algorithm

Bv38 (3)

Bv40 (3)

Br38 (3)

Bl57 (3)

Window Width and Level

500/100

410/10

410/10

1600/-500

Reconstruction Comments: The reconstruction field of view is limited to 33.2cm using the flash spiral scan mode. An additional smaller DFOV reconstruction that only includes the heart and aorta will increase spatial resolution of the coronary vessels.

 

Reconstruction Parameters

Coronal Open Field

Sagittal Open Field

Slice Thickness

 3 mm

3 mm

Reconstruction Spacing

 3 mm

3 mm

Reconstruction Algorithm

Bv40 (3)

Bv40 (3)

Window Width and Level

410/10

410/10

Reconstruction Comments: The reconstruction field of view is limited to 33.2cm using the flash spiral scan mode. An additional smaller DFOV reconstruction that only includes the heart and aorta will increase spatial resolution of the coronary vessels.

 

Contrast Parameters

Parameters

Contrast Type

Non-ionic

Contrast Volume

80-100 mL

Saline Flush

30 mL

Injection Rate

5-7 mL/sec.

Oral Contrast

N/A

Contrast Volume

N/A

Comments: Bolus tracking is used ideal with a 300 HU trigger value on the ascending aorta. A saline flush can be used to soften the SVC and limit beam hardening artifact.

Other Comments: To successfully scan a patient using the flash spiral mode, the heart rate should be 60-70bpm and the patient should be no larger than average size to avoid increased image noise. Typically, flash spiral gated chest acquisitions are performed with an ECG trigger of 60%. It may also be useful to trigger at 30% for patients with higher heart rates. The ECG trigger must be changed utilizing the scan protocol assistant, so it may be beneficial to build two separate protocols, diastolic and systolic, when programming the scanner.