Pulmonary embolism: Accuracy and safety of a negative CT pulmonary angiogram and value of a negative D-dimer assay to exclude CT pulmonary angiogram-detectable pulmonary embolism

R. M. Subramaniam, T. Chou, M. Swarbrick, N. Karalus

Research output: Contribution to journalArticle

2 Scopus citations


This is a retrospective study to determine the accuracy and safety of a negative CT pulmonary angiogram (CTPA) based on clinical outcome and to determine the usefulness of a negative D-dimer assay before CTPA. A total of 483 patients with a negative CTPA study were followed up for 3 months, with the aim of detecting episodes of venous thromboembolism and mortality. Three hundred and forty-nine patients had an immunochromatographic D-dimer assay called 'Simplify', carried out before a CTPA examination. Seventy-eight patients had a negative D-dimer assay and a negative CTPA. Three patients had a negative D-dimer assay and a positive CTPA. All three patients had a moderate pretest clinical probability. Of the 483 patients who had a negative CTPA and a 3-month follow up, 444 (92%) were alive and 39 (8%) had died. Of the 444 patients who were alive, none had any further suspected episode of thromboembolism or had received anticoagulation therapy within the follow-up period. Of those who died, none of the deaths was thought to be as a result of pulmonary embolism (PE). Single-detector helical CT can be used safely as the primary diagnostic test to evaluate PE. Negative Simplify D-dimer assay and low pretest clinical probability exclude CTPA-detectable PE, and a CTPA is unnecessary in this cohort of patients.

Original languageEnglish (US)
Pages (from-to)424-428
Number of pages5
JournalAustralasian Radiology
Issue number5
Publication statusPublished - Oct 1 2006



  • Computed tomography pulmonary angiogram
  • D-dimer
  • Pulmonary embolism

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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