title: Ten years of imaging for pulmonary embolism: too many scans or the tip of an iceberg?
abstract: OBJECTIVE
  To examine the number and nature of investigations performed for suspected pulmonary embolism (PE) in a large teaching hospital and the change in incidence and severity of PE over a decade.
  
  
  METHODS
  In this retrospective study, all patients investigated for suspected PE using computed tomography pulmonary angiography (CTPA) or lung scintigraphy during 10 years to March 2012 were identified and their records reviewed. In the final year, all reportedly positive CTPA cases were reviewed and PE severity calculated, for comparison with similar historical data.
  
  
  RESULTS
  From 2002 to 2012, total annual investigations for suspected acute PE increased by 163% (805 to 2121). CTPA increased by 325% (475 to 2019). Detection of PE increased by 121% (193 to 426 per annum), with stable distribution of severity scores. The positive scan rate decreased from 24% to 20%. The mean age of patients being investigated for PE increased from 56 to 63 years.
  
  
  CONCLUSIONS
  Increased detection of PE is not due to disproportionate increase in small PEs, but to increased detection of PE of all severities. This finding supports the hypothesis that PE is more common in the general population than previously appreciated, which may represent an iceberg phenomenon of previously undetected disease.
authors.affiliation: Dept. of Radiology, Royal Infirmary of Edinburgh, UK. Electronic address: n.c.d.morley@halscion.com.
authors.forename: N C D
authors.initials: NC
authors.lastname: Morley
authors.affiliation: Dept. of Radiology, Royal Infirmary of Edinburgh, UK.
authors.forename: K C
authors.initials: KC
authors.lastname: Muir
authors.affiliation: Clinical Research Imaging Centre, University of Edinburgh, UK.
authors.forename: S
authors.initials: S
authors.lastname: Mirsadraee
authors.affiliation: Clinical Research Imaging Centre, University of Edinburgh, UK.
authors.forename: E J R
authors.initials: EJ
authors.lastname: van Beek
authors.affiliation: Dept. of Radiology, Royal Infirmary of Edinburgh, UK.
authors.forename: J T
authors.initials: JT
authors.lastname: Murchison
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D006784:Hospitals, Teaching / Q000706:statistics & numerical data; D006801:Humans; D015994:Incidence; D007479:Iopamidol / Q000031:analogs & derivatives; D008168:Lung / Q000000981:diagnostic imaging; D008875:Middle Aged; D011651:Pulmonary Artery / Q000000981:diagnostic imaging*; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging / Q000453:epidemiology*; D011856:Radiographic Image Enhancement; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013668:Technetium Tc 99m Aggregated Albumin; D036542:Tomography, Spiral Computed; D055815:Young Adult
chemical_list: D019275:Radiopharmaceuticals; D013668:Technetium Tc 99m Aggregated Albumin; C057937:iomeprol; D007479:Iopamidol