Emergency Radiology

, Volume 26, Issue 1, pp 29–35 | Cite as

Computed tomography for suspected pulmonary embolism results in a large number of non-significant incidental findings and follow-up investigations

  • Omar Anjum
  • Helena Bleeker
  • Robert OhleEmail author
Original Article



Computed tomographic pulmonary angiograms (CTPAs) are often ordered to evaluate pulmonary embolism (PE) in the emergency department (ED). The increase use of CTPA has led to an increase in incidental findings, often of low clinical significance. Our objectives were to (1) assess the prevalence and clinical significance of incidental findings identified in patients evaluated with CTPAs for PE in the ED, (2) evaluate follow-up investigations for these incidental findings, and (3) assess the utility of routine chest X-rays done prior to CTPA.


This is a historical cohort study of adult patients, presenting to two tertiary care EDs from January–December 2015, evaluated with CTPA for possible PE. Two reviewers’ extracted data from electronic CT records in a standardized fashion with inter-rater reliability reported using the kappa statistic. We measured the prevalence of PE and stratified non-PE findings according to alternative diagnoses and incidental findings. Data were reported as mean and standard deviation (SD). Univariate analyses were performed with t test for continuous variables.


A total of 1708 studies were included (mean 62 years (SD 16.7), 56.9% female). PE was found in 233 (13.6%) patients. A total of 223 (13.1%) patients had an incidental finding, the majority of which included pulmonary nodules (n = 83, 37.2%) and adenopathy (n = 26, 11.6%). Of the incidental findings, 197 (88.3%) were non-significant and led to no definitive diagnosis of cancer. In patients who underwent both CTPA and chest X-ray, X-ray reports revealed the same diagnosis in 77% of PE-negative patients without missing a clinically significant incidental finding.


Incidental findings are as common as a diagnosis of PE in patients undergoing CTPA. They are rarely clinically significant. Chest radiograph remains a reasonable initial investigation as it can aid in identifying alternative diagnoses especially in the setting of a low pre-test probability for PE.


Computed tomography Incidental findings Pulmonary embolism Chest X-ray 


Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.


  1. 1.
    Brown M, Vance S, Kline J (2005) An emegency department guideline for the diagnosis of pulmonary embolism: an outcome study. Acad Emerg Med 12(1):20–25CrossRefGoogle Scholar
  2. 2.
    Caroline C (2014) Lung cancer screening with low dose CT. Radiol Clin N Am 52(1):27–46CrossRefGoogle Scholar
  3. 3.
    Chandra S, Sarkar P, Chandra D, Ginsberg N, Cohen R (2013) Finding an alternative diagnosis does not justify increased use of CT-pulmonary angiography. BMC Pulm Medicine 13:9CrossRefGoogle Scholar
  4. 4.
    Chen Y, Gray B, Bandiera G (2014) Variation in the utilization and positivity rates of CT pulmonary angiography among emergency physicians at a tertiary academic emergency department. Emerg Radiol 22(3):1–9Google Scholar
  5. 5.
    Chen Y, Gray B, Bandiera G, MacKinnon D, Deva D (2015) Variation in the utilization and positivity rates of CT pulmonary angiography among emergency physicians at a tertiary academic emergency department. Emerg Radiol 22(3):221–229CrossRefGoogle Scholar
  6. 6.
    Cochon L, McIntyre K, Nicolas J, Baez A (2017) Incremental diagnostic quality gain of CTA over V/Q scan in the assessment of pulmonary embolism by means of a Wells score Bayesian model: results from the ACDC collaboration. Emerg Radiol 24(4):355–359CrossRefGoogle Scholar
  7. 7.
    Costa A, Basseri H, Sheikh A, Stiell I, Dennie C (2014) The yield of CT pulmonary angiograms to exclude acute pulmonary embolism. Emerg Radiol 21(2):133–141CrossRefGoogle Scholar
  8. 8.
    Courtney D, Miller C, Smithline H, Klekowski N, Hogg M, Kline J (2010) Prospective multicenter assessment of interobserver agreement for radiologist interpretation of multidetector computerized tomographic angiography for pulmonary embolism. J Thromb Haemost 8:533–539CrossRefGoogle Scholar
  9. 9.
    Foley P, Hamaad A, El-Gendi H, Leyva F (2010) Incidental cardiac findings on computed tomography imaging of the thorax. BMC Res Notes 3:326CrossRefGoogle Scholar
  10. 10.
    Hall W, Truitt S, Scheunemann L (2009) The prevalence of clinically relevant incidental findings on chest computed tomographic angiograms ordered to diagnose pulmonary embolism. Arch Intern Med 169(21):1961–1965CrossRefGoogle Scholar
  11. 11.
    Jansen A, van Aalst-Cohen E, Hutten B, Buller H, Kastelein J, Prins M (2005) Guidelines were developed for data collection from medical records for use in retrospective analyses. J Clin Epidemiol 58(3):269–274CrossRefGoogle Scholar
  12. 12.
    Kline J, Mitchell A, Kabrhel C, Richman P, Courtney D (2004) Clinical criteria to prevent unnecessary diagnostic testing in emergency department patients with suspected pulmonary embolism. J Thromb Haemost 2(8):1247–1255CrossRefGoogle Scholar
  13. 13.
    MacMahon H, Naidich D, Goo J, Lee K, Leung A, Mayo J, … Bankier A (2017) Guidelines for management of incidental pulmonary nodules detected on CT images: from the Fleischner Society 2017. Radiology 284(1):228–243Google Scholar
  14. 14.
    Perelas A, Dimou A, Saenz A, Rhee J, Teerapuncharoen K, Rowden A, Elger G (2015) Incidental findings on computed tomography angiography in patients evaluated for pulmonary embolism. Ann Stat 12(5):689–695Google Scholar
  15. 15.
    Schattner A (2009) Computed tomographic pulmonary angiography to diagnose acute pulmonary embolism: the good, the bad, and the ugly: comment on “The prevalence of clinically relevant incidental findings on chest computed tomographic angiograms ordered to diagnose pulmonary embolism”. Arch Intern Med 169(21):1966–1968CrossRefGoogle Scholar
  16. 16.
    Shah U, Freya S, Nandakumar K (2012) Evaluation of incidental findings other than PE on CT pulmonary angiogram. Eur Respir J 40:648Google Scholar
  17. 17.
    Tsai K, Gupta E, Haramati L (2004) Pulmonary atelectasis: a frequent alternative diagnosis in patients undergoing CT-PA for suspected pulmonary embolism. Emerg Radiol 10(5):282–286CrossRefGoogle Scholar
  18. 18.
    van Strijen M, Bloem J, de Monye W, Kieft G, Pattynama P, van den Berg-Huijsmans A, Huisman M (2005) Helical computed tomography and alternative diagnosis in patients with excluded pulmonary embolism. J Thromb Haemost 3(11):2449–2456CrossRefGoogle Scholar
  19. 19.
    van Es J, Douma R, Schreuder S, Middledorp S, Kamphuisen P, Gerdes V, Beenen L (2013) Clinical impact of findings supporting an alternative diagnosis on CT pulmonary angiography in patients with suspected pulmonary embolism. Chest 144(6):1893–1899CrossRefGoogle Scholar
  20. 20.
    Weir I, Drescher F, Cousin D, Fraser E, Lee R, Berman L, … Fine J (2010) Trends in use and yield of chest computed tomography with angiography for diagnosis of pulmonary embolism in a Connecticut hospital emergency department. Conn Med 74:5-9Google Scholar
  21. 21.
    Wells P, Anderson D, Rodger M, Stiell I, Dreyer J, Barnes D, … Kovacs M (2001) Excluding pulmonary embolism at the bedside without diagnostic imaging: management of patients with suspected pulmonary embolism presenting to the emergency department by using a simple clinical model and d-dimer. Ann Intern Med 135(2):98–107Google Scholar
  22. 22.
    Zhonghua S, Jing L (2017) Diagnostic yield of CT pulmonary angiography in the diagnosis of pulmonary embolism: a single centre experience. Interv Cardiol 9(5):191–198Google Scholar

Copyright information

© American Society of Emergency Radiology 2018

Authors and Affiliations

  1. 1.Department of Undergraduate MedicineUniversity of OttawaOttawaCanada
  2. 2.The Department of Emergency Medicine, Health Science North Research InstituteNorthern Ontario School of MedicineThunder BayCanada
  3. 3.The Ottawa HospitalOttawaCanada

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