Pulmonary embolism: helical CT could not exclude it.

Clinical bottom line (level 4)

  1. About 40% of patients suspected of having pulmonary embolism had it.
  2. A positive helical CT made pulmonary embolism more likely (LR+19) , but a negative one did not rule it out (LR-0.23) .
Remy-Jardin et al: Radiology 1992; 185: 381-387
Expires October 2003

The study

Setting: teaching hospital, France

42 patients (aged range 21-65 years; mean 34, 71% male) suspected pulmonary embolism or unexplained pleuroparenchymal changes on chest X-ray

Independent blinded reference standard, applied in all patients from a consecutive ?appropriate spectrum.
Reference standard:
  • positive pulmonary angiogram within in 24 hours
Diagnostic test: spiral volumetric CT performed using single-breath holding technique, contrast-enhanced. Positive if complete or partial filling defect, or free-floating thrombus, or "railway track" sign. Inability to suspend respiration not an exclusion criteria

The evidence

pre-test probability of pulmonary embolism: 43%, (95% CI: 28% to 58%)

diagnostic test pulmonary embolism no pulmonary embolism LR+
(95% CI)		 post-test probability LR-
(95% CI)		 post-test probability
CT positive 14 1 19
(2.7 to 130) 		93% 0.23
(0.10 to 0.55) 		15%
total 18 24

Citation

  1. Remy-Jardin M, Remy J, Wattinne L, et al: Central pulmonary thromboembolism: diagnosis with spiral volumetric CT with single-breath-holding technique - comparison with pulmonary angiography. Radiology 1992; 185: 381-387
Contributor: Chris Ball and Clare Wotton, October 2000
Reviewer:

Clinical Question.
Patient suspected pulmonary embolism
Intervention or Exposure helical CT
Outcome diagnosis