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Updated: Aug 14, 2026
A Multicenter MRI Protocol for the Evaluation and Quantification of Deep Vein Thrombosis
Published on: June 2, 2015
Safety of a single duplex scan to exclude deep venous thrombosis
B Wolf1, D M Nichols, J L Duncan
1Department of General Surgery, Raigmore Hospital, Inverness, UK.
Insights
Withholding anticoagulation after a single negative duplex scan for deep venous thrombosis (DVT) is safe. A follow-up scan is recommended only if clinical suspicion remains high or calf veins were not visualized.
Area of Science:
- Vascular Medicine
- Diagnostic Imaging
Background:
- Current guidelines recommend repeat ultrasonography or venography after a negative scan for suspected deep venous thrombosis (DVT).
- This practice aims to detect potentially missed calf vein thrombosis.
Purpose of the Study:
- To assess the safety of withholding anticoagulation based on a single negative duplex scan in patients with suspected DVT.
Main Methods:
- Retrospective analysis of duplex scan reports, case notes, and general practitioner questionnaires.
- Outcome measured: adverse thromboembolic events (symptomatic DVT, pulmonary embolism) within 3 months post-scan.
Main Results:
- 429 negative duplex scans in 352 patients were analyzed.
- Four possible adverse events occurred, yielding an adverse outcome rate of 1.1% per patient and 0.9% per leg.
Conclusions:
- A single, complete, negative duplex scan supports safely withholding anticoagulation.
- Repeat scanning is advised for persistent high clinical suspicion or inadequate visualization of calf veins.
Background:
Guidelines advocate that a negative ultrasonographic scan needs to be followed by venography, or a repeat scan after 1 week, to detect potentially missed calf vein thrombosis. This study aimed to evaluate whether anticoagulation can safely be withheld on the basis of a single negative duplex scan in patients presenting with suspected deep venous thrombosis (DVT).
Methods:
Duplex scan reports, case notes and questionnaires returned by general practitioners of patients with suspected DVT were analysed retrospectively. The main outcome measure was occurrence of an adverse thromboembolic event, a symptomatic DVT or a pulmonary embolism, within 3 months after a negative duplex scan.
Results:
Some 537 patients had 706 leg scans performed, the majority because of leg symptoms or to look for indirect evidence of pulmonary embolism. Among 352 patients, who had 429 negative leg scans, four possible adverse events were identified. The rate of adverse outcome was therefore 1.1 per cent per patient and 0.9 per cent per leg.
Conclusion:
Withholding anticoagulation in patients who had a single, complete, negative duplex scan is safe. A repeat scan should be performed if there is ongoing high clinical suspicion and considered in patients in whom the calf veins could not be visualized.
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