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The Significance of Incidental Findings on Computed Tomography of the Chest
The Journal of Emergency Medicine, Vol. -, No. -, pp. 1–4, 2018 Ó 2018 Elsevier Inc. All rights reserved. 0736-4679/$ - see front matter
https://doi.org/10.1016/j.jemermed.2018.06.001
Clinical Reviews THE SIGNIFICANCE OF INCIDENTAL FINDINGS ON COMPUTED TOMOGRAPHY OF THE CHEST Anna L. Waterbrook, MD, Marie A. Manning, MSIV, and James E. Dalen, MD, MPH The University of Arizona College of Medicine, Tucson, Arizona Corresponding Address: Anna L. Waterbrook, MD, Department of Emergency Medicine, The University of Arizona, P.O. Box 245057, Tucson, AZ 85724-5057
, Abstract—Background: Computed tomography (CT) of the chest has replaced lung scans and pulmonary angiography as the criterion standard for the diagnosis of pulmonary embolism (PE). Most of these examinations are negative for PE, but they frequently have incidental findings that may require further evaluation. Objective: In order to examine common incidental findings and their possible clinical ramifications and required workup, we reviewed data from relevant studies in which chest CTs were performed and incidental findings discovered. Discussion: The most common incidental findings on chest CT are pulmonary nodules and lymph nodes. Nodules are significantly more commonly found in smokers and are also more likely to be malignant in smokers. The recently updated 2017 Fleischner Society recommendations provide guidance to clinicians in deciding which nodules should be further evaluated. Enlarged lymph nodes similarly represent potential malignancy and most will need further evaluation with positron emission tomography scans or by transbronchial needle aspiration. Conclusions: Enlarged lymph nodes and pulmonary nodules are both common incidental findings on chest CT. Each represents the potential for malignancy, and under certain conditions requires additional workup and further evaluation. The majority will be benign, even in high-risk populations. However, because of the increasing prevalence of the chest CT and the frequency with which incidental findings will be seen, it is important that the emergency physician be aware of common features and recommended
subsequent evaluation. reserved.
Ó 2018 Elsevier Inc. All rights
, Keywords—Chest CT; Fleischner Society recommendations; Incidental findings; Lymph nodes; Pulmonary nodules
INTRODUCTION Computed tomography (CT) of the chest has replaced lung scans and pulmonary angiography as the criterion standard for the diagnosis of pulmonary embolism (PE). CT is much faster to perform, has higher sensitivity and higher specificity than pulmonary angiograms or lung scans, and is being used with increasing frequency (1,2). The majority of chest CTs are performed to diagnose or exclude PE, and while most of these examinations are negative for PE, they frequently have incidental findings that may require further evaluation (3–5). Stein et al. compared the findings by chest CT with chest radiography (CXR) performed within 24 h of CT in 332 patients in whom the CT was negative for PE (4) (Table 1). The 2 incidental findings found on CT but not CXR that might require further evaluation or follow-up were pulmonary nodules (seen in 9.3%) and lymph nodes (seen in 7.8%) (3). Hall et al. also reported the prevalence of incidental CT findings in patients suspected of PE (5). Of 589 patients, 141 (24%) had a new incidental finding that might require additional
Reprints are not available from the authors.
RECEIVED: 28 April 2018; ACCEPTED: 5 June 2018 1
2
A. L. Waterbrook et al.
than 10 mm in diameter (9). Swensen et al. reported similar findings in 2832 nodules (8). Sixty-one percent were <4 mm, and 95% were <7 mm in diameter.
Table 1. Abnormalities Present on Computed Tomography but Not Chest Radiography* Abnormality
%
Atelectasis Nodule Emphysema Pleural effusion Lymph node Scarring
16.6 9.3 8.4 7.8 7.8 7.0
* Data from Stein et al. (4).
evaluation. The most common findings requiring additional evaluation were pulmonary nodules in 73 cases (13%) and lymph nodes in 51 cases (9%). To examine common incidental findings and their possible clinical ramifications and required workup, we reviewed data from relevant studies in which chest CTs were performed and incidental findings discovered. DISCUSSION Incidence of Pulmonary Nodules Discovered on CXR and Chest CT Calcified nodules are considered benign and do not require follow-up (6). Noncalcified pulmonary nodules are frequent incidental findings in patients who have CT to rule out PE. As noted in Table 2, the average incidence of nodules is about 10% (4–6). The incidence in smokers is much higher (20–70%) and varies with the smoking history and the patient’s age (6,9). As shown in Table 2, the incidence of nodules is much higher by CT than by CXR (4,5,9). CT can identify nodules as small as 1 mm, whereas nodules <5 mm are rarely detected by CXR. In the series by Henschke et al., only 16% of 136 nodules #5 mm detected by CT were detected by CXR (9). Size of Pulmonary Nodules Detected by Chest CT The majority of nodules detected by chest CT are <10 mm in diameter. Henschke et al. reported that of 584 nodules, 58% were less than 5 mm in diameter, and 89% were less
Incidence of Lung Cancer in Follow-up of Pulmonary Nodules The main concern for pulmonary nodules is that they may be early signs of non–small cell lung cancer. Follow-up studies have reported that in patients with no history of cancer when the nodule is detected, the incidence of cancer is clearly related to the size of the nodule when first detected by CT (6,9). Henschke et al. reported the follow-up of nodules in 2897 smokers (9). The incidence of cancer at follow-up was 0 in 238 patients with nodules <5 mm. With nodules 5–9 mm, the incidence of cancer was 6%. The incidence in 616 patients with nodules <10 mm was 2%. Benjamin et al. reported that the incidence of cancer in a 2-year follow-up of patients without known cancer whose nodule was <10 mm was approximately 1% (6). Which Pulmonary Nodules Need Additional Evaluation? The majority of pulmonary nodules are small and not evident on CXR. Fortunately, nearly all small (<10 mm diameter) nodules are benign at follow-up (6,9). The Fleischner Society published updated guidelines for the management of pulmonary nodules detected on CT scans in 2017 (7). Their recommendations are shown in Table 3. The Fleischner Society also includes recommendations for patients with ‘‘subsolid’’ nodules (7). These nodules are recognized by their ground glass or part solid appearance. Their recommendations are the same for smokers and nonsmokers. For single subsolid nodules <6 mm, no follow-up is recommended. For single ground glass subsolid nodules >6 mm, CT at 6–12 months and then every 2 years until 5 years is recommended. For single part solid nodules, CT at 3–6 months and then annually for 5 years is recommended (9). For multiple subsolid nodules, CT at 3–6 months is recommended regardless of size, with subsequent management dependent on findings at that time
Table 2. Incidence of Noncalcified Pulmonary Nodules Author
No. of Patients
Patients
CT (%)
CXR (%)
Stein et al. (4) Hall et al. (5) Benjamin et al. (6) MacMahon et al. (7) Swensen et al. (8) Henschke et al. (9)
322 589 3446 — 1049 1000
PE negative CT for PE Nodules <10 mm Smokers >50 years of age Smokers >50 years of age Smokers >60 years of age
9 13 9.7 51 69 23
1.5 9 — — — 7
CT = computed tomography of the chest; CXR = chest radiography; PE = pulmonary embolism.
Significance of Incidental Findings on Chest CT Table 3. Fleischner Society Recommendations for Followup of Pulmonary Nodules Nodule Type Single
Multiple
Nodule Size (mm)
Low Risk*
#6
No follow-up
6–8
CT 6–12 months
>8 #6
CT 3 months No follow-up
6–8
CT 3–6 months
>8
CT 3–6 months
High Risk* Optional CT at 12 months CT 6–12 and 18– 24 months CT 3 months Optional CT at 12 months CT 3–6 and 18– 24 months CT 3–6 months and 18–24 months
CT = computed tomography of the chest. * According to the 2017 Fleischner Society recommendations, the designation of a patient of high or low risk should be based on consideration of all relevant risk factors, including nodular size, location, multiplicity, and growth rate (9). Patients with emphysema or fibrosis seen on CT and smokers should be considered high risk. Additional contributing factors include patient’s age, sex, race, and family history (8).
(8). Enlarged lymph nodes are almost as common on chest CT as pulmonary nodules (4,5). The concern is that enlarged nodes may represent metastasis from non–small cell lung cancer. Unlike pulmonary nodules, size of the node is not predictive of malignancy (10,11). Nodes <1 cm may be malignant (10,11). Most recommend further evaluation of all chest lymph nodes $1 cm in diameter (5,11,12). Positron emission tomography scans are often combined with CT findings to diagnose malignancy (11). Transbronchial needle aspiration may also be used to confirm malignancy (11). As emergency physicians, we will not necessarily organize further workup for these incidental findings; however, we often need to inform patients of these findings and thus should at least be familiar with the likely further workup so that we can provide our patients with appropriate anticipatory guidance. CONCLUSIONS Chest CTs have become the criterion standard test for diagnosing PE and are performed with increasing frequency. However, with increased chest CTs performed, there will be an increase in incidental findings found on chest CTs. The 2 most likely incidental findings that may require additional evaluation are pulmonary nodules and enlarged lymph nodes. Pulmonary nodules may
3
require follow-up CT scans to evaluate for malignancy and other potential complications and should be managed according to the recently updated 2017 Fleischner Society recommendations. While many pulmonary nodules necessitate follow-up, solid pulmonary nodules #6 mm in diameter in low-risk adults >35 years of age generally need no additional follow-up according to these new updated guidelines. Enlarged lymph nodes may require positron emission tomography scans or transbronchial biopsy procedures to rule out metastatic non–small cell lung cancer. Given the frequency with which chest CTs are performed in the ED and incidental findings encountered, it is important for emergency physicians to be knowledgeable about the outpatient follow-up and management of these incidental findings.
REFERENCES 1. Karabulut N, Kiroglu Y. Relationship of parenchymal and pleural abnormalities with acute pulmonary embolism: CT findings in patients with and without embolism. Diagn Interv Radiol 2008;14: 189–96. 2. Weir ID, Drescher F, Cousin D, et al. Trends in use and yield of chest computed tomography with angiography for diagnosis of pulmonary embolism in a Connecticut hospital emergency department. Conn Med 2010;74:5–9. 3. Dalen JE, Waterbrook AL. Why are nearly all CT angiograms for suspected pulmonary embolism negative? Am J Med 2017;130: 247–8. 4. Stein PD, Matta F, Sedrick JA, et al. Ancillary findings on CT pulmonary angiograms and abnormalities on chest radiographs in patients in whom pulmonary embolism was excluded. Clin Appl Thromb Hemost 2012;18:201–5. 5. Hall WB, Truitt SG, Scheunemann LP, et al. The prevalence of clinically relevant incidental findings on chest computed tomographic angiograms ordered to diagnose pulmonary embolism. Arch Intern Med 2009;169:1961–5. 6. Benjamin MS, Drucker EA, McLoud TC, et al. Small pulmonary nodules: Detection at chest CT and outcome. Radiology 2003; 226:489–93. 7. MacMahon H, Naidich DP, Goo JM, et al. Guidelines for management of incidental pulmonary nodules detected on CT images: a statement from the Fleischner Society. Radiology 2017;284: 228–43. 8. Swensen SJ, Jett JR, Hartman TE, et al. Lung cancer screening with CT: Mayo Clinic experience. Radiology 2003;226:756–61. 9. Henschke CI, Yankelevitz DF, Naidich DP, et al. CT screening for lung cancer: suspiciousness of nodules according to size on baseline scans. Radiology 2004;231:164–8. 10. Prenzel KL, Monig SP, Sinning JM. Lymph node size and metastatic infiltration in non-small cell lung cancer. Chest 2003;123:463–7. 11. Yasufuku K, Nakajima T, Motoori K, et al. Comparison of endobronchial ultrasound, positron emission tomography, and CT for lymph node staging of lung cancer. Chest 2006;130:710–8. 12. Rusch VW. Lymph nodes in lung cancer. Chest 2015;147:1203–4.
4
A. L. Waterbrook et al.
ARTICLE SUMMARY 1. Why is this topic important? Computed tomography (CT) of the chest has replaced lung scans and pulmonary angiography as the criterion standard for the diagnosis of pulmonary embolism (PE). Most of these examinations are negative for PE, but they frequently have incidental findings that may require additional evaluation. 2. What does this review attempt to show? This article discusses the most common incidental findings encountered on chest CTs, the risks associated with these findings, and the appropriate follow-up and management of these findings. 3. What are the key findings? The 2 most likely incidental CT findings in patients suspected of PE that may require additional evaluation are pulmonary nodules and enlarged lymph nodes. Pulmonary nodules may require biopsy procedures or followup CT scans, while enlarged lymph nodes potential require positron emission tomography scans or transbronchial biopsy procedures. While many pulmonary nodules and enlarged lymph nodes necessitate follow-up, solid pulmonary nodules #6 mm in diameter in low-risk adults >35 years of age generally need no additional follow-up according to the updated 2017 Fleischner Society guidelines. 4. How is patient care impacted? By understanding the most common incidental findings discovered on chest CT and the most current guidelines on their management, we will be able to better counsel patients on the appropriate follow-up of these potentially concerning incidental findings discovered on chest CT, while also minimizing unnecessary concern, further radiation exposure, and cost when possible.
https://doi.org/10.1016/j.jemermed.2018.06.001
Clinical Reviews THE SIGNIFICANCE OF INCIDENTAL FINDINGS ON COMPUTED TOMOGRAPHY OF THE CHEST Anna L. Waterbrook, MD, Marie A. Manning, MSIV, and James E. Dalen, MD, MPH The University of Arizona College of Medicine, Tucson, Arizona Corresponding Address: Anna L. Waterbrook, MD, Department of Emergency Medicine, The University of Arizona, P.O. Box 245057, Tucson, AZ 85724-5057
, Abstract—Background: Computed tomography (CT) of the chest has replaced lung scans and pulmonary angiography as the criterion standard for the diagnosis of pulmonary embolism (PE). Most of these examinations are negative for PE, but they frequently have incidental findings that may require further evaluation. Objective: In order to examine common incidental findings and their possible clinical ramifications and required workup, we reviewed data from relevant studies in which chest CTs were performed and incidental findings discovered. Discussion: The most common incidental findings on chest CT are pulmonary nodules and lymph nodes. Nodules are significantly more commonly found in smokers and are also more likely to be malignant in smokers. The recently updated 2017 Fleischner Society recommendations provide guidance to clinicians in deciding which nodules should be further evaluated. Enlarged lymph nodes similarly represent potential malignancy and most will need further evaluation with positron emission tomography scans or by transbronchial needle aspiration. Conclusions: Enlarged lymph nodes and pulmonary nodules are both common incidental findings on chest CT. Each represents the potential for malignancy, and under certain conditions requires additional workup and further evaluation. The majority will be benign, even in high-risk populations. However, because of the increasing prevalence of the chest CT and the frequency with which incidental findings will be seen, it is important that the emergency physician be aware of common features and recommended
subsequent evaluation. reserved.
Ó 2018 Elsevier Inc. All rights
, Keywords—Chest CT; Fleischner Society recommendations; Incidental findings; Lymph nodes; Pulmonary nodules
INTRODUCTION Computed tomography (CT) of the chest has replaced lung scans and pulmonary angiography as the criterion standard for the diagnosis of pulmonary embolism (PE). CT is much faster to perform, has higher sensitivity and higher specificity than pulmonary angiograms or lung scans, and is being used with increasing frequency (1,2). The majority of chest CTs are performed to diagnose or exclude PE, and while most of these examinations are negative for PE, they frequently have incidental findings that may require further evaluation (3–5). Stein et al. compared the findings by chest CT with chest radiography (CXR) performed within 24 h of CT in 332 patients in whom the CT was negative for PE (4) (Table 1). The 2 incidental findings found on CT but not CXR that might require further evaluation or follow-up were pulmonary nodules (seen in 9.3%) and lymph nodes (seen in 7.8%) (3). Hall et al. also reported the prevalence of incidental CT findings in patients suspected of PE (5). Of 589 patients, 141 (24%) had a new incidental finding that might require additional
Reprints are not available from the authors.
RECEIVED: 28 April 2018; ACCEPTED: 5 June 2018 1
2
A. L. Waterbrook et al.
than 10 mm in diameter (9). Swensen et al. reported similar findings in 2832 nodules (8). Sixty-one percent were <4 mm, and 95% were <7 mm in diameter.
Table 1. Abnormalities Present on Computed Tomography but Not Chest Radiography* Abnormality
%
Atelectasis Nodule Emphysema Pleural effusion Lymph node Scarring
16.6 9.3 8.4 7.8 7.8 7.0
* Data from Stein et al. (4).
evaluation. The most common findings requiring additional evaluation were pulmonary nodules in 73 cases (13%) and lymph nodes in 51 cases (9%). To examine common incidental findings and their possible clinical ramifications and required workup, we reviewed data from relevant studies in which chest CTs were performed and incidental findings discovered. DISCUSSION Incidence of Pulmonary Nodules Discovered on CXR and Chest CT Calcified nodules are considered benign and do not require follow-up (6). Noncalcified pulmonary nodules are frequent incidental findings in patients who have CT to rule out PE. As noted in Table 2, the average incidence of nodules is about 10% (4–6). The incidence in smokers is much higher (20–70%) and varies with the smoking history and the patient’s age (6,9). As shown in Table 2, the incidence of nodules is much higher by CT than by CXR (4,5,9). CT can identify nodules as small as 1 mm, whereas nodules <5 mm are rarely detected by CXR. In the series by Henschke et al., only 16% of 136 nodules #5 mm detected by CT were detected by CXR (9). Size of Pulmonary Nodules Detected by Chest CT The majority of nodules detected by chest CT are <10 mm in diameter. Henschke et al. reported that of 584 nodules, 58% were less than 5 mm in diameter, and 89% were less
Incidence of Lung Cancer in Follow-up of Pulmonary Nodules The main concern for pulmonary nodules is that they may be early signs of non–small cell lung cancer. Follow-up studies have reported that in patients with no history of cancer when the nodule is detected, the incidence of cancer is clearly related to the size of the nodule when first detected by CT (6,9). Henschke et al. reported the follow-up of nodules in 2897 smokers (9). The incidence of cancer at follow-up was 0 in 238 patients with nodules <5 mm. With nodules 5–9 mm, the incidence of cancer was 6%. The incidence in 616 patients with nodules <10 mm was 2%. Benjamin et al. reported that the incidence of cancer in a 2-year follow-up of patients without known cancer whose nodule was <10 mm was approximately 1% (6). Which Pulmonary Nodules Need Additional Evaluation? The majority of pulmonary nodules are small and not evident on CXR. Fortunately, nearly all small (<10 mm diameter) nodules are benign at follow-up (6,9). The Fleischner Society published updated guidelines for the management of pulmonary nodules detected on CT scans in 2017 (7). Their recommendations are shown in Table 3. The Fleischner Society also includes recommendations for patients with ‘‘subsolid’’ nodules (7). These nodules are recognized by their ground glass or part solid appearance. Their recommendations are the same for smokers and nonsmokers. For single subsolid nodules <6 mm, no follow-up is recommended. For single ground glass subsolid nodules >6 mm, CT at 6–12 months and then every 2 years until 5 years is recommended. For single part solid nodules, CT at 3–6 months and then annually for 5 years is recommended (9). For multiple subsolid nodules, CT at 3–6 months is recommended regardless of size, with subsequent management dependent on findings at that time
Table 2. Incidence of Noncalcified Pulmonary Nodules Author
No. of Patients
Patients
CT (%)
CXR (%)
Stein et al. (4) Hall et al. (5) Benjamin et al. (6) MacMahon et al. (7) Swensen et al. (8) Henschke et al. (9)
322 589 3446 — 1049 1000
PE negative CT for PE Nodules <10 mm Smokers >50 years of age Smokers >50 years of age Smokers >60 years of age
9 13 9.7 51 69 23
1.5 9 — — — 7
CT = computed tomography of the chest; CXR = chest radiography; PE = pulmonary embolism.
Significance of Incidental Findings on Chest CT Table 3. Fleischner Society Recommendations for Followup of Pulmonary Nodules Nodule Type Single
Multiple
Nodule Size (mm)
Low Risk*
#6
No follow-up
6–8
CT 6–12 months
>8 #6
CT 3 months No follow-up
6–8
CT 3–6 months
>8
CT 3–6 months
High Risk* Optional CT at 12 months CT 6–12 and 18– 24 months CT 3 months Optional CT at 12 months CT 3–6 and 18– 24 months CT 3–6 months and 18–24 months
CT = computed tomography of the chest. * According to the 2017 Fleischner Society recommendations, the designation of a patient of high or low risk should be based on consideration of all relevant risk factors, including nodular size, location, multiplicity, and growth rate (9). Patients with emphysema or fibrosis seen on CT and smokers should be considered high risk. Additional contributing factors include patient’s age, sex, race, and family history (8).
(8). Enlarged lymph nodes are almost as common on chest CT as pulmonary nodules (4,5). The concern is that enlarged nodes may represent metastasis from non–small cell lung cancer. Unlike pulmonary nodules, size of the node is not predictive of malignancy (10,11). Nodes <1 cm may be malignant (10,11). Most recommend further evaluation of all chest lymph nodes $1 cm in diameter (5,11,12). Positron emission tomography scans are often combined with CT findings to diagnose malignancy (11). Transbronchial needle aspiration may also be used to confirm malignancy (11). As emergency physicians, we will not necessarily organize further workup for these incidental findings; however, we often need to inform patients of these findings and thus should at least be familiar with the likely further workup so that we can provide our patients with appropriate anticipatory guidance. CONCLUSIONS Chest CTs have become the criterion standard test for diagnosing PE and are performed with increasing frequency. However, with increased chest CTs performed, there will be an increase in incidental findings found on chest CTs. The 2 most likely incidental findings that may require additional evaluation are pulmonary nodules and enlarged lymph nodes. Pulmonary nodules may
3
require follow-up CT scans to evaluate for malignancy and other potential complications and should be managed according to the recently updated 2017 Fleischner Society recommendations. While many pulmonary nodules necessitate follow-up, solid pulmonary nodules #6 mm in diameter in low-risk adults >35 years of age generally need no additional follow-up according to these new updated guidelines. Enlarged lymph nodes may require positron emission tomography scans or transbronchial biopsy procedures to rule out metastatic non–small cell lung cancer. Given the frequency with which chest CTs are performed in the ED and incidental findings encountered, it is important for emergency physicians to be knowledgeable about the outpatient follow-up and management of these incidental findings.
REFERENCES 1. Karabulut N, Kiroglu Y. Relationship of parenchymal and pleural abnormalities with acute pulmonary embolism: CT findings in patients with and without embolism. Diagn Interv Radiol 2008;14: 189–96. 2. Weir ID, Drescher F, Cousin D, et al. Trends in use and yield of chest computed tomography with angiography for diagnosis of pulmonary embolism in a Connecticut hospital emergency department. Conn Med 2010;74:5–9. 3. Dalen JE, Waterbrook AL. Why are nearly all CT angiograms for suspected pulmonary embolism negative? Am J Med 2017;130: 247–8. 4. Stein PD, Matta F, Sedrick JA, et al. Ancillary findings on CT pulmonary angiograms and abnormalities on chest radiographs in patients in whom pulmonary embolism was excluded. Clin Appl Thromb Hemost 2012;18:201–5. 5. Hall WB, Truitt SG, Scheunemann LP, et al. The prevalence of clinically relevant incidental findings on chest computed tomographic angiograms ordered to diagnose pulmonary embolism. Arch Intern Med 2009;169:1961–5. 6. Benjamin MS, Drucker EA, McLoud TC, et al. Small pulmonary nodules: Detection at chest CT and outcome. Radiology 2003; 226:489–93. 7. MacMahon H, Naidich DP, Goo JM, et al. Guidelines for management of incidental pulmonary nodules detected on CT images: a statement from the Fleischner Society. Radiology 2017;284: 228–43. 8. Swensen SJ, Jett JR, Hartman TE, et al. Lung cancer screening with CT: Mayo Clinic experience. Radiology 2003;226:756–61. 9. Henschke CI, Yankelevitz DF, Naidich DP, et al. CT screening for lung cancer: suspiciousness of nodules according to size on baseline scans. Radiology 2004;231:164–8. 10. Prenzel KL, Monig SP, Sinning JM. Lymph node size and metastatic infiltration in non-small cell lung cancer. Chest 2003;123:463–7. 11. Yasufuku K, Nakajima T, Motoori K, et al. Comparison of endobronchial ultrasound, positron emission tomography, and CT for lymph node staging of lung cancer. Chest 2006;130:710–8. 12. Rusch VW. Lymph nodes in lung cancer. Chest 2015;147:1203–4.
4
A. L. Waterbrook et al.
ARTICLE SUMMARY 1. Why is this topic important? Computed tomography (CT) of the chest has replaced lung scans and pulmonary angiography as the criterion standard for the diagnosis of pulmonary embolism (PE). Most of these examinations are negative for PE, but they frequently have incidental findings that may require additional evaluation. 2. What does this review attempt to show? This article discusses the most common incidental findings encountered on chest CTs, the risks associated with these findings, and the appropriate follow-up and management of these findings. 3. What are the key findings? The 2 most likely incidental CT findings in patients suspected of PE that may require additional evaluation are pulmonary nodules and enlarged lymph nodes. Pulmonary nodules may require biopsy procedures or followup CT scans, while enlarged lymph nodes potential require positron emission tomography scans or transbronchial biopsy procedures. While many pulmonary nodules and enlarged lymph nodes necessitate follow-up, solid pulmonary nodules #6 mm in diameter in low-risk adults >35 years of age generally need no additional follow-up according to the updated 2017 Fleischner Society guidelines. 4. How is patient care impacted? By understanding the most common incidental findings discovered on chest CT and the most current guidelines on their management, we will be able to better counsel patients on the appropriate follow-up of these potentially concerning incidental findings discovered on chest CT, while also minimizing unnecessary concern, further radiation exposure, and cost when possible.