Computed tomography for suspected pulmonary embolism results in a large number of non-significant incidental findings and follow-up investigations
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.
KeywordsComputed 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.
- 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
- 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.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.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.Shah U, Freya S, Nandakumar K (2012) Evaluation of incidental findings other than PE on CT pulmonary angiogram. Eur Respir J 40:648Google Scholar
- 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.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.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