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 triggered | 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 60 bpm 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 protocols for scan details). All scans are performed using the ALARA principle. 3D post-processing is performed with this protocol. |
Technical Parameters | Parameters |
kVp | 120 |
Effective mAs | Use dose reduction software |
Care Dose Reference mAs | 320 |
Time (Rotation) | 0.28 sec |
Average Acquisition Time | 1-2 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-R interval of the ECG wave. 100 kVp is used for most average size patients. ECG dose modulation is not necessary for this protocol. Dose reduction software is used to reduce patient dose. |
Reconstruction Parameters | Soft Tissue | Thin Data | Thin Data | Lung |
Slice Thickness | 3 mm | 0.75 mm | 0.75mm | 3 mm |
Reconstruction Spacing | 3 mm | 0.5 mm | 0.5 mm | 3 mm |
Reconstruction Algorithm | B26f ASA | I41f (3) | I46f (3) | B80f |
Window Width and Level | 500/100 | 500/100 | 500/100 | 1600/-500 |
Reconstruction Comments: The reconstruction field of view is limited to 33.2cm using the flash spiral scan mode. Open field reconstructions are also performed to evaluate extra cardiac pathology. |
Reconstruction Parameters | Soft Tissue Open Field | Thin Data Open Field | |
Slice Thickness | 3mm | 0.75 mm | |
Reconstruction Spacing | 3 mm | 0.5 mm | |
Reconstruction Algorithm | B30f | B20f | |
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. Open field reconstructions are also performed to evaluate extra cardiac pathology. |
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: Test Bolus is used to calculate the peak contrast enhancement to determine the correct scan delay. Bolus tracking can also be used. |
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.