Pulmonary embolism: diagnosis with spiral CT and ventilation-perfusion scanning--correlation with pulmonary angiographic results or clinical outcome

Radiology. 1998 Jul;208(1):201-8. doi: 10.1148/radiology.208.1.9646814.


Purpose: To compare the accuracy of spiral computed tomography (CT) with that of ventilation-perfusion (V-P) scintigraphy in the diagnosis of pulmonary embolism (PE).

Materials and methods: Fifty-four patients in whom indeterminate V-P scans or discordant clinical and scintigraphic results were obtained underwent both V-P scanning and contrast material-enhanced spiral CT. The reference standard was pulmonary angiographic results in 26 patients (group I) or clinical outcome in 28 (group II).

Results: Six (25%) of 24 group I patients had proved PE. The prospective sensitivity and specificity for segmental or subsegmental PE were 67% and 100%, respectively, and the positive and negative predictive values were 100% and 90%, respectively. In two group II patients, V-P scans had high probability for acute embolism, but spiral CT scans showed only chronic PE; in one patients, the V-P scan had low probability and the CT scan was positive for acute PE. An alternative CT diagnosis was established in four (31%) of 13 patients in whom a normal or low-probability V-P scan was obtained. Clinical outcome was consistent with spiral CT results in all cases.

Conclusion: Spiral CT has greater accuracy and specificity than V-P scanning in patients with an unresolved diagnosis and may be useful as the primary screening technique for PE.

Publication types

  • Comparative Study

MeSH terms

  • Acute Disease
  • Adult
  • Aged
  • Aged, 80 and over
  • Angiography
  • Angiography, Digital Subtraction
  • Chronic Disease
  • Contrast Media
  • Female
  • Follow-Up Studies
  • Humans
  • Image Processing, Computer-Assisted
  • Iohexol / analogs & derivatives
  • Iothalamate Meglumine
  • Male
  • Middle Aged
  • Predictive Value of Tests
  • Probability
  • Prospective Studies
  • Pulmonary Embolism / diagnostic imaging*
  • Pulmonary Embolism / drug therapy
  • Radionuclide Imaging
  • Radiopharmaceuticals
  • Reference Standards
  • Sensitivity and Specificity
  • Technetium Tc 99m Aggregated Albumin
  • Tomography, X-Ray Computed / methods*
  • Treatment Outcome
  • Ventilation-Perfusion Ratio


  • Contrast Media
  • Radiopharmaceuticals
  • Technetium Tc 99m Aggregated Albumin
  • Iohexol
  • iopromide
  • Iothalamate Meglumine