Acquisition Phase

Phase Included

Scan Delay

Respiration Phase

Anatomical Coverage

Non Contrast

Yes

N/A

Inspiration

Carina through the apex of the heart

Arterial Phase

Yes

Test bolus or Bolus trigger

Inspiration

Carina through the apex of the heart

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 60bpm or lower. Using this mode will result in extremely low dose exams. Cardiac calcium scoring is routinely performed with a cardiac CTA to evaluate coronary artery disease (see calcium score protocol for scan details). All scans are performed using the ALARA principle. A 3D Post Processing is performed with this protocol.

 

Technical Parameters

Parameters

kVp

100 or 120

Effective mAs

CareDose

Care Dose Reference mAs

320

Time (Rotation)

0.28 sec

Average Acquisition Time

0.4 sec

Collimation

128 x 0.6mm

Pitch Value

3.4

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 to R interval of the ECG wave. 100kVp is used for most average size patients. ECG dose modulation is not necessary for this protocol. See Flash calcium score for details.

 

Reconstruction Parameters

Soft Tissue

Thin Data

Lung

Slice Thickness

 3mm

 0.75mm

 3mm

Reconstruction Spacing

 3mm

 0.5mm

 3mm

Reconstruction Algorithm

 B26f ASA

 B26f ASA / I41f

 B80f

Window Width and Level

 500/100

 500/100

 1600/-500

Reconstruction Comments: There is a limited reconstruction field of view when using the flash spiral mode to 33.2cm.  Iterative reconstructions are also performed to improve image noise. Open field reconstructions are also performed to evaluate extra cardiac pathology.

 

Contrast Parameters

Parameters

Contrast Type

Non ionic

Contrast Volume

80-100ml

Saline Flush

30ml

Injection Rate

5-7 mL/sec

Oral Contrast

N/A

Contrast Volume

N/A

Comments: Test Bolus is used to calculate the peak contrast enhancement to determine the correct scan delay.


Other Comments: To successfully scan a patient using the flash spiral mode, the heart rate should be 60bpm or less and the patient should be no larger than average size to avoid increased image noise. See Cardiac CT Flow Chart below for more information on selecting the correct protocol based on the patient's heart rate and rhythm. Coronary CTA images should visualize the coronary arteries and left ventricle with adequate opacification of IV contrast. Images should limit venous contamination while flushing contrast out of the right ventricle to prevent image artifacts.