You are asked about the merits of different imaging to diagnose pulmonary embolism. Complete the table giving advantages and disadvantages of different imaging modalities used to diagnose pulmonary embolism?

Score
Advantages
Disadvantages
CTPA
  • Readily available around the clock in most centres1
  • Excellent accuracy1
  • Strong validation in prospective management outcome studies1
  • Low rate of inconclusive results (3–5%)1
  • May provide alternative diagnosis if PE excluded1
  • Short acquisition time1
  • Can evaluate IVC and lower extremity thrombi when used in conjunction with venography1
    Max 2
  • Radiation exposure, particularly to young female breast tissue
  • Exposure to iodine contrast
  • Tendency to overuse because of easy accessibility
  • Clinical relevance of CTPA diagnosis of subsegmental PE unknown
Planar V/Q Scan
  • Almost no contraindications
  • Low radiation and contrast medium sparing investigation
  • Relatively inexpensive
  • Strong validation in prospective management outcome studies
  • Not readily available in all centres1
  • Interobserver variability in interpretation1
  • Results reported as likelihood ratios1
  • Inconclusive in 50% of cases1
  • Cannot provide alternative diagnosis if PE excluded1
    Max 2
Pulmonary Angiography
  • Historical gold standard
  • Invasive procedure1
  • Not readily available in all centres1
    Max 2