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. | |