RadteraCTA Thoracic Outlet (Neutral + Provocative Positioning)
CTA+ ContrastVascular
Indications
- Suspected arterial thoracic outlet syndrome (positional arm ischemia, subclavian compression/aneurysm)
- Suspected venous TOS / effort thrombosis (Paget-Schroetter syndrome)
- Post-cervical-rib or post-decompression assessment
Patient prep
- IV access CONTRALATERAL to the symptomatic side
- Explain the two positions in advance: neutral (arms down at sides) and provocative (arms abducted/elevated overhead)
- Screen eGFR/contrast allergy
Contrast
Agentiodinated (e.g. iohexol 350 or iopamidol 370)
RouteIV (contralateral arm)
DoseSplit dose — ≈75 mL per acquisition at 4-5 mL/s with saline flush; allow ~5 min between injections
TimingBolus tracking in the descending aorta below the arch, trigger ~80-100 HU, for each position; add a venous pass ~30-45 s after each arterial acquisition when venous TOS is the question
Technique
- TWO acquisitions: neutral arms-down, then provocative arms-elevated (abduction/external rotation, head neutral or turned per protocol) — compression is positional and may only appear on the provocative series
- Coverage thoracic inlet (lower cervical spine) through the proximal humeri/carina, identical range both positions
- 100-120 kV; thin 0.625-1 mm recon; MIP/VR of subclavian-axillary vessels in both positions for side-by-side comparison
- Assess the three compression sites: scalene triangle, costoclavicular space, retropectoralis minor space
Series / Sequences
| # | Series / Sequence | Plane | Thickness | Notes |
|---|---|---|---|---|
| 1 | Arterial — neutral position | axial | 0.625-1 mm | Baseline vessel caliber |
| 2 | Arterial — arms elevated | axial | 0.625-1 mm | Positional compression, poststenotic dilatation |
| 3 | Venous pass (selective) | axial | 1-2 mm | ~30-45 s post-arterial each position; subclavian vein thrombosis/compression |
| 4 | MIP/3D both positions | 3D | VR/MIP | Side-by-side positional comparison |
Key points
- The exam is a comparison: same coverage, two arm positions — report caliber change of the subclavian artery/vein between neutral and provocative series and the structure causing compression (cervical rib, scalene, clavicle/first rib)
- Some degree of positional venous compression occurs in asymptomatic people — correlate with symptoms
- Venous phases are essential when effort thrombosis is suspected; look for chronic wall thickening and collaterals
- Arterial complications to report: poststenotic dilatation/aneurysm, mural thrombus, distal embolization
Source: Researched — verify against your institution
Reference template — verify and adapt to your scanner, vendor and institution before clinical use. Not a substitute for clinical judgment.