Diagnosis of pulmonary embolism: comparison of CT angiography and MR angiography in canines

J Vasc Interv Radiol. 1999 Mar;10(3):309-18. doi: 10.1016/s1051-0443(99)70036-9.


Purpose: To compare the sensitivity and specificity of helical computed tomographic angiography (CTA), CTA with multiplanar reconstructions (MPR)/three-dimensional-shaded surface display (3D-SSD), and gadolinium-enhanced magnetic resonance angiography (MRA) for pulmonary embolism (PE) detection.

Materials and methods: Gelatin sponge emboli were introduced into the femoral veins of seven dogs and conventional digital subtraction angiography (CA), CTA, and MRA performed. Images from CTA, CTA with MPR/3D-SSD, and MRA were reviewed for the presence of PE in lobar and segmental arteries, and subsegmental zones. Postmortem angiography and CA were the gold standard.

Results: There were 50 emboli in the 294 vessels/zones analyzed. The sensitivity of CTA for the two readers was 76% (95% confidence interval [CI]; 64%-88%) and 64% (95% CI; 50%-78%), and for the two MRA readers was 52% (95% CI; 38%-66%) and 48% (95% CI; 34%-62%). CTA was more sensitive than MRA when PE were subdivided by vessel caliber. Specificity was high for CTA and MRA among all readers (98.8%-99.6%). MPR/3D-SSD did not improve results of axial CT. MRA perfusion defects were 46% and 47% sensitive and 100% specific. Interobserver agreement was high for CTA and MRA (kappa 0.92 and 0.93, respectively). The average diameter of vessels with emboli was 3.7 mm +/- 1.06.

Conclusion: Helical CTA is more sensitive than three-dimensional gadolinium-enhanced MRA for the detection of PE. Both CTA and MRA are highly specific for PE detection and demonstrate high interobserver agreement. MPR/3D-SSD did not increase CTA performance over axial images alone.

Publication types

  • Comparative Study

MeSH terms

  • Angiography / methods*
  • Animals
  • Diagnostic Errors
  • Disease Models, Animal
  • Dogs
  • False Negative Reactions
  • Magnetic Resonance Angiography*
  • Pulmonary Artery / diagnostic imaging*
  • Pulmonary Artery / pathology*
  • Pulmonary Embolism / diagnosis*
  • Sensitivity and Specificity
  • Tomography, X-Ray Computed*