Risk of pulmonary embolism after a negative spiral CT angiogram in patients with pulmonary disease: 1-year clinical follow-up study

Radiology. 2002 May;223(2):461-7. doi: 10.1148/radiol.2232010913.


Purpose: To evaluate the effect of pulmonary disease on diagnostic utility of spiral computed tomographic (CT) angiography in clinical practice.

Materials and methods: Three hundred thirty-four patients, including 215 patients with pulmonary disease (group 1) and 119 patients with no history of respiratory disorder (group 2), were referred for thin-collimation CT angiography of the pulmonary circulation as the first-line diagnostic test. Patients with negative angiograms who had not received anticoagulation therapy and who could be clinically followed up at 3 months, 6 months, and 1 year were considered in the final study groups (n = 185); 135 patients had lung disease (group 3), and 50 patients had no history of a respiratory disorder (group 4).

Results: Between groups 3 and 4, no significant differences were found in the referral location, age, and risk factors. Confident evaluation of pulmonary arteries down to the subsegmental level was performed in 31 (23%) patients in group 3 and in 15 (30%) in group 4 (P =.5). Three episodes of acute pulmonary embolism (PE), all fatal, were diagnosed in group 3 patients; two cases occurred 14 days and one case occurred 6 months after the negative spiral CT scan. The negative predictive value of spiral CT angiography was 98% (175 of 178) in the study group in which follow-up was performed, with no significant difference between the values in groups 3 (98% [132 of 135]) and 4 (100% [50 of 50]).

Conclusion: Underlying respiratory disease does not affect the negative predictive value of thin-collimation CT angiography, which appears to be a reliable tool in the work-up in this subgroup of patients with acute PE.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Angiography
  • Chi-Square Distribution
  • False Negative Reactions
  • Female
  • Follow-Up Studies
  • Humans
  • Lung Diseases / complications*
  • Lung Diseases / diagnostic imaging*
  • Male
  • Middle Aged
  • Pulmonary Embolism / diagnostic imaging*
  • Pulmonary Embolism / etiology*
  • Risk Factors
  • Statistics, Nonparametric
  • Tomography, X-Ray Computed / methods*