Synopsis
Interpret compression ultrasound by anatomical scope, technical adequacy, clinical probability, and the correct repeat-imaging pathway.
- Do not let routine ultrasound delay resuscitation or vascular escalation for shock, suspected pulmonary embolism, or a blue, severely painful, rapidly swollen limb.
- After an adequate negative limited proximal study, repeat timing depends on the pathway: NICE uses 6–8 days for non-pregnant likely DVT with positive D-dimer, whereas RCOG uses repeat scans on days 3 and 7 in pregnancy when suspicion remains high.
- Limited proximal CUS samples two or three named venous territories—usually common femoral and popliteal, with femoral-vein assessment depending on protocol—rather than a universal continuous segment. The report must name what was examined; unresolved calf disease calls for whole-leg ultrasound, while suspected pelvic or IVC disease or inconclusive ultrasound may require CT or MR venography.
Key red flags
Cyanosis, severe tense swelling, neurological deficit or weak arterial signals suggests phlegmasia and possible threatened limb.
Syncope, hypotension, severe breathlessness, pleuritic pain or haemoptysis requires an urgent pulmonary embolism assessment.
A technically inadequate study with persistent high suspicion leaves DVT unresolved and needs a defined repeat or alternative test.
Partial or complete failure of venous collapse under graded pressure, with compatible intraluminal material, supports acute DVT in that named segment.
Thrombus in popliteal, femoral or iliac territory is proximal DVT and generally changes anticoagulation management promptly.
Whole-leg swelling, groin or back pain, abnormal common femoral phasicity or prominent collaterals may indicate pelvic disease outside routine compression views.
Pain, obesity, oedema, wounds, dressings, plaster and deep pelvic anatomy can prevent adequate visualisation or compression and must be reported.
Investigation priorities
Assess two or three named proximal venous territories rapidly, usually common femoral and popliteal with femoral-vein assessment depending on protocol.
Management branches
A non-pregnant adult has Wells score 3, negative adequate proximal ultrasound and positive D-dimer.
- Verify that this case report explicitly documents the common femoral, femoral and popliteal territories stated in the stem and records no technical limitation; other limited protocols may examine only two named territories.
- Stop interim therapeutic anticoagulation while preserving any unrelated established long-term anticoagulant indication.
The entire leg is swollen, iliac thrombosis is suspected, or ultrasound is repeatedly inadequate or discordant.