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Updated: Aug 15, 2026

A Multicenter MRI Protocol for the Evaluation and Quantification of Deep Vein Thrombosis
Published on: June 2, 2015
A comparison of computerised strain gauge plethysmography with D-dimer testing in screening for deep-vein thrombosis
1Department of Clinical Pharmacology, Aberdeen Royal Infirmary, Foresterhill, Aberdeen, UK. david.j.williams@arh.grampian.scot.nhs.uk
Abstract:
There has been a significant increase in the amount of diagnostic testing performed to confirm or refute a diagnosis of deep-vein thrombosis (DVT), often in low-risk patients. D-dimer testing and computer-assisted strain gauge plethysmography (SGP) are rapid, inexpensive methods of excluding DVT and, in combination with a clinical probability score for DVT, both have been used to accurately exclude DVT. D-dimer testing, SGP and a combination of both in excluding DVT were compared in 243 ambulant outpatients who followed a prespecified investigation protocol. The negative-predictive value of D-dimer testing alone was 100%, 93.9% (95% CI 93.6-94.1) and 80% (95% CI 73.7-86.3) in patients with a low, moderate and high pretest probability (PTP) score for DVT respectively. The corresponding results for SGP were 95.6% (95% CI 95.5-95.7), 86.1% (95% CI 85.9-86.4) and 77.8% (95% CI 75.9-79.7) in patients with a low, moderate and high PTP score for DVT respectively. D-dimer testing provided a rapid, cost-effective method for excluding DVT in low-risk ambulant patients, which was superior to SGP. Combined use of the modalities did not improve any aspect of clinical decision making.
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