CT Protocols: (Brain, ENT, Spine, Vascular) - Department of Radiology

Orbit: (Vascular Mass or Carotid-Cavernous Fistula)
(Protocol – Adult: # 2.3 – Pediatric: # 12.5 & 12.6)
Billing:
Setup:
DFOV:
Exam:
Reformats:
Part 1:
Part 2:
Part 3:
1. CT Orbit (with and without)
2. Contrast
34 Revised 7/22/09 (Gentry/Ranallo)
1. Patient Supine, AP and lateral scouts, no gantry angle
2. Extend the scouts to include aortic arch and superior vena cava for smart prep.
3. Always do exam with and without contrast
4. Patient Positioning: Tilt the patients head so that a line connecting the lateral
canthus of the eye and the EAC is perpendicular to the CT tabletop (see head
CT protocol). You may need to put a foam pad under the occiput to get the head
in this position.
5. Ask the patient to look straight ahead and hold their eyes in a very still position.
6. Start the scans at the infraorbital rim and scan through the top of the orbit
14 cm (14-16 cm)
Routine Orbit CT without contrast
- Standard algorithm (Recon 1) only (no bone algorithm images & no reformats)
Dynamic CT scans through lesion (as described below and on next page)
- Choose eight 2.5 mm slices through the mass for dynamic scans
- Smart prep over the superior vena cava
- To be monitored by ENT attending or ENT fellow if possible
- Adults: Inject 100 ml of 240mg/ml at 3.5 ml per sec (Injection time = 28.5 sec)
(note: use 150ml of 240mg/ml if a CT of the head will also be obtained)
- Pediatrics: Inject 1 ml/lb (2 ml/kg) of 240 mg/ml contrast at 2 ml per sec
- Begin scanning with the arrival of contrast in the superior vena cava
- 1 image per sec X 5 (Using Cine Mode), then 1 image every 3 sec. X 3, then 1
image every 10 seconds X 2 (5 groups using Axial Mode with a Prep Group
Delay of 2 sec and 9 sec respectively) (scan time = 34 sec).
- Use 100 kV; 300 mA for adults, 150 mA for peds less than 6 y/o.
- Allow all of the contrast to be injected then do Part 3
- no reformats or bone algorithm with Part 2, only axial standard 2.5 mm images
Post-contrast Orbit CT
- Scan as in routine orbit “with contrast” protocol performing all 3 Recons:
standard, bone and, thin bone
1. Only do 2D-Reconstructions from the Part 3 contrast-enhanced images
2. Do 2 mm x 2 mm 2D-reformations using both the standard 1.25 mm images
(Recon 1) AND the bone 0.625 mm images (Recon 3) in the coronal and bilateral
oblique sagittal planes as outlined below.
3. Do not send the 0.625 mm (Recon 3) bone images to PACS