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Original Research: Pulmonary Vascular Disease |

Clinical Impact of Findings Supporting an Alternative Diagnosis on CT Pulmonary Angiography in Patients With Suspected Pulmonary EmbolismAlternative Findings on CT Pulmonary Angiography FREE TO VIEW

Josien van Es, MD, PhD; Renée A. Douma, MD, PhD; Sanne M. Schreuder, MD; Saskia Middeldorp, MD, PhD; Pieter W. Kamphuisen, MD, PhD; Victor E. A. Gerdes, MD, PhD; Ludo F. M. Beenen, MD
Author and Funding Information

From the Department of Vascular Medicine (Drs van Es, Douma, Middeldorp, and Gerdes) and Department of Radiology (Drs Schreuder and Beenen), Academic Medical Center, Amsterdam; Department of Vascular Medicine (Dr Kamphuisen), University of Groningen, University Medical Center Groningen, Groningen; and Department of Internal Medicine (Dr Gerdes), Slotervaart Hospital, Amsterdam, The Netherlands.

Correspondence to: Josien van Es, MD, PhD, Department of Vascular Medicine, Academic Medical Center F4-136, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands; e-mail: j.vanes@amc.uva.nl


Funding/Support: The authors have reported to CHEST that no funding was received for this study.

Reproduction of this article is prohibited without written permission from the American College of Chest Physicians. See online for more details.


Chest. 2013;144(6):1893-1899. doi:10.1378/chest.13-0157
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Background:  CT pulmonary angiography (CTPA) is commonly used as the first imaging test in the diagnostic workup of patients with suspected pulmonary embolism (PE). Other CTPA findings may provide an alternative explanation for signs and symptoms in these patients, but the clinical impact is not clear.

Methods:  In 203 consecutive patients with suspected PE, we prospectively evaluated the clinical implication of abnormalities on CTPA. Alternative diagnoses were defined on clinical grounds before and after CTPA. Subsequent diagnostic tests and therapeutic consequences were assessed by criteria defined a priori.

Results:  Sixty-one of the 203 patients (30%) had no abnormality on CTPA. Thirty-nine patients (19%) were given a diagnosis of PE. Before CTPA, alternative diagnoses were suspected in 97 patients (48%). Findings supporting an alternative diagnosis were detected in 88 patients (43%). In 28 patients, this was a new finding; in 18, a conclusive and previously unknown alternative diagnosis was made on the basis of the CTPA results. Overall, the findings supporting alternative diagnoses had therapeutic consequences in 10 patients (4.9%). Incidental findings (nodules and enlarged lymph nodes) requiring diagnostic procedures were present in 17 patients (8.4%), with one (0.5%) having a therapeutic consequence.

Conclusions:  In patients undergoing CTPA for suspected PE, findings supporting an alternative diagnosis were found in almost one-half of the patients. However, in only a few patients, the alternative diagnosis had therapeutic consequences. Hence, CTPA should principally be used to confirm or exclude PE in high-probability cases but not to establish an alternative diagnosis.

Figures in this Article

During the past decade, CT pulmonary angiography (CTPA) has been increasingly used as the primary imaging test to confirm or exclude pulmonary embolism (PE).1 Compared with the previous reference standard method (ventilation/perfusion scintigraphy and pulmonary angiography), CTPA is widely available, quick, and noninvasive. Furthermore, CTPA has a high sensitivity (80%-100%) and specificity (96%-100%).2,3 Another potential advantage of CTPA is the possibility to detect additional abnormalities that may explain the patient’s complaints.4,5 However, CTPA also harbors a risk of incidental findings, such as intrapulmonary nodules or enlarged lymph nodes. Although these abnormalities may suggest, for example, malignant disease, follow-up of these incidental findings likely involves extra hospital visits, invasive procedures, and repeated CT scanning and, therefore, is a burden for the patient.4 Furthermore, the exposure to radiation after repeat imaging is especially a concern because it is considered an important risk factor for developing a malignancy.68 The reported proportion of nodules that are actually malignant is approximately 1%.9 Low-dose chest CT screening has not been proven to decrease the rate of detection of advanced cancer or to affect mortality as a result of lung cancer.9,10

Still, some clinicians use CTPA to detect potential alternative diagnoses, even if the clinical suspicion of PE is low.11 Several studies revealed that CTPA will yield a reliable finding that supports an alternative diagnosis in 25% to 52% of patients with suspected PE.4,5,12 However, it is unclear whether these alternative diagnoses, mostly pneumonia, could also be established by clinical presentation, laboratory results, and a chest radiograph before CTPA.13

In this study, we assessed the clinical impact of CTPA findings that support alternative diseases on CTPA ordered in the diagnostic workup for PE in terms of diagnostic or therapeutic consequences. Furthermore, we investigated whether these alternative diagnoses were already established or highly suspected before CT scanning.

Patients

Consecutive inpatients and outpatients with a clinical suspicion of acute PE in whom CTPA was performed between August 2008 and April 2009 at the Academic Medical Center, Amsterdam, The Netherlands, were eligible for this analysis. Patients with severely impaired renal function (creatinine clearance < 30 mL/min by the Cockroft-Gault formula), who were aged < 18 years, or who were pregnant were excluded. The study protocol was approved by the institutional review board with a waiver for informed consent.

Study Design

The pretest clinical probability of PE was considered unlikely with a Wells score of ≤ 4 points and likely with a Wells score > 4 points.14 Patients categorized as PE unlikely underwent d-dimer testing. A CTPA was performed in all patients with an abnormal d-dimer test result (> 500 μg/L) and in all patients classified as PE likely.15

Evaluation of the possibility or presence of alternative diagnoses was performed at three time points:

  • 1. Before CT scanning. The ordering physician was requested to inform the radiologist to explicitly mention an alternative diagnosis other than PE on the basis of signs, symptoms, physical examination, laboratory results, and chest radiograph.

  • 2. After CT scanning. Patients were treated by the attending physician on the basis of the CTPA results in combination with other clinical information. The treating physician was asked whether a finding supportive of an alternative diagnosis on CTPA could indeed explain the signs and symptoms and whether these findings had diagnostic or therapeutic consequences. All additional diagnostic tests and therapeutic consequences were recorded separately.

  • 3. Three-month follow-up. For this analysis, we evaluated whether findings or diagnoses documented at the time of inclusion had been revised 3 months after CTPA.

CTPA Analysis

CTPA was performed with a 64-slice multidetector CT scanner (Sensation 64; Siemens AG). Scan parameters were as follows: collimation of 64 × 0.6 mm with 100 kV and 200 mA and rotation time of 0.5 with a pitch of 1.4 and an automatic tube current modulation (CARE Dose 4D Automatic Exposure Control; Siemens AG). IV contrast medium 100 mL at 4 mL/s (ULTRAVIST 300; Bayer Pharma AG) was administered through an 18-gauge peripheral cannula followed by saline chase 40 mL at 4 mL/s. Images were reconstructed at 1-mm axial, sagittal, and coronal slices in soft kernel with additional coronal maximum intensity projection reformats. All studies were read by the attending radiologist or resident, with a second read by an experienced emergency radiologist, using a picture archiving and communication system (IMPAX 4.5, Agfa-Gevaert Group) with standard window settings and the possibility to change these settings without restrictions. A CTPA was considered to be nondiagnostic in detecting PE if opacification of the vessels was insufficient (subjective interpretation of available contrast in the pulmonary arteries of < 200 Hounsfield units) or in the case of major artifacts. For CTPA evaluation, a structured reporting format was used.

CTPA Findings
Findings Supporting an Alternative Diagnosis:

Findings supporting an alternative diagnosis were defined as all that potentially provided an alternative diagnosis for the patient’s signs and symptoms (eg, chest pain, shortness of breath, hypoxemia, tachycardia). Such findings included pneumonia, pleural effusion, tumor (noted on the report as a new mass suspicious for malignancy or progression of known malignant disease possibly combined with adenopathy), significant atelectasis, bronchiolitis, pericardial effusion, (progressive) COPD, heart failure, or other diagnoses. Significant atelectasis was only determined if it was not secondary to pleural effusion. In the case of multiple abnormalities found on one CTPA, all were reported, and the most likely one to explain the patient’s symptoms was registered as a finding supporting an alternative diagnosis.

This classification was irrespective of the assessment of whether the finding truly explained the signs and symptoms (only that it potentially could explain the symptoms) (Fig 1, group A). For instance, if a pneumonic infiltrate was present, it was classified as an alternative finding. However, if judging more strictly, the infiltrate could be deemed too small to explain the clinical status. Therefore, an additional differentiation was made, selecting only those CT scans with findings that sufficiently explained the patient’s signs and symptoms as concluded by the treating physician (Fig 1, group B, Table 1). Furthermore, we classified the findings as new if the CTPA results were not visible on the chest radiograph before CT scanning.

Figure Jump LinkFigure 1. Flowchart of findings supporting an alternative diagnosis and the subsequent results in diagnostic and therapeutic consequences.Grahic Jump Location
Table Graphic Jump Location
Table 1 —Prevalence of Radiographic Findings, Findings Supporting an Alternative Diagnosis, and Incidental Findings in the Diagnostic Workup of PE in 203 CTPA Scans

Data are presented as No. (%, 95% CI). CTPA = CT pulmonary angiography; PE = pulmonary embolism.

a 

Group A: findings supporting an alternative diagnosis that potentially explained the signs and symptoms of the patient.

b 

Group B: findings supporting an alternative diagnosis that sufficiently explained the signs and symptoms of the patient, as was concluded by the treating physician.

c 

Patients may be classified as having more than one outcome (PE, alternative diagnosis, incidental finding, etc).

Incidental Findings:

Incidental findings were pulmonary nodules and enlarged mediastinal or hilar lymph nodes. Adenopathy that required follow-up were (1) any lymph node with a short-axis diameter of > 1 cm and not associated with pneumonia, (2) any lymph node > 3 cm in diameter, or (3) the presence of multiple mediastinal or hilar lymph nodes. A pulmonary lymph node was defined as a new finding only if no mass or nodule was evident on previous imaging or if no history of malignancy, mass, or nodule was noted in the patient’s medical record. A pulmonary mass of > 1 cm that was not described as a nodule or lymph node was not considered an incidental finding but categorized as supporting the alternative diagnosis of tumor.

Other Findings:

Findings that did not support an alternative diagnosis and required less urgent or no follow-up were previously known or nonprogressive emphysema (changes described as emphysematous or consistent with emphysema or COPD); mild atelectasis (read as atelectasis, collapse, or volume loss described as dependent or involving fewer than three pulmonary segments); previously known, unchanged systemic disease, such as sarcoidosis, systemic scleroderma, or TB; cardiomegaly; skeletal findings (degenerative changes and other nonmalignant anomalies in skeletal structures); and other pulmonary processes, such as scarring or calcifications.

Consequences of Findings Detected on the CTPA

A finding was considered to have diagnostic consequences in case one or more of the following procedures was performed: a thoracocentesis, bronchoscopy, sputum culture, consultation of a pulmonologist or cardiologist, or performance of other diagnostic tests. A therapeutic consequence was classified when antibiotics, diuretics, corticosteroids, or chemotherapy was administered or if thoracentesis was performed as a direct consequence of the CTPA findings or following a diagnostic thoracentesis. Both diagnostic and therapeutic consequences were only considered if a diagnosis was new and not already known before CT scanning (Fig 1).

Statistical Analysis

Normally distributed variables are presented as mean ± SD, and nonnormally distributed variables are expressed as medians with ranges. The total number of presenting patients was consistently used as the denominator in all percentages mentioned, unless specified otherwise. Exact 95% CIs of proportions were calculated with SPSS version 19.0 (IBM Corporation) software.

Patient Characteristics

A total of 203 consecutive patients with suspected PE were included. The mean age was 57 ± 17 years, 77 patients (38%) were men, 26 (13%) had a history of COPD, 10 (4.9%) had a history of heart failure, and 59 (29%) had an active malignancy (Table 2).

Table Graphic Jump Location
Table 2 —Clinical Characteristics

Data are presented as No. (%) unless otherwise indicated.

Suspected Alternative Diagnoses Before CTPA

Before CT scanning, alternative diagnoses were considered by the treating physician in 97 patients (48%). These included pneumonia in 37 (18%), isolated pleural fluid in 12 (5.9%), (progression of) tumor in seven (3.4%), and COPD in seven (3.4%).

CTPA Findings

PE was diagnosed in 39 patients (19%). Sixty-one (30%) had no abnormalities on CTPA.

Findings Supporting an Alternative Diagnosis:

CTPA findings supporting an alternative diagnosis that potentially explained the patient’s symptoms (group A) were found in 88 patients (Fig 1, Table 1); three patients also had PE. Among these alternative diagnoses were one or more pneumonic infiltrates in 28 patients (14%), significant pleural effusion in 27 (13%), and (progression of) tumor/metastases in 10 (4.9%). These were new findings in 28 patients (Fig 1, Table 1).

Of the 88 patients with findings supporting an alternative diagnosis, the findings were scored as sufficiently explaining the symptoms in 56 of the CTPA scans. Of these, 18 were new findings (Fig 1, Table 1).

Incidental Findings:

An incidental finding was found in 23 patients (11%) of whom 17 (8.3%) required further diagnostic evaluation (five diagnostic punctures, five consultations with a pulmonologist, and seven follow-ups by radiologic imaging). In one patient, the diagnostic evaluation of the lymph node had therapeutic consequences (ie, cancer).

Other Findings:

In 74 patients (36%), minor findings seen on CTPA were considered unrelated to the clinical signs and symptoms and did not require follow-up. These findings included residual abnormalities due to previous infections, mild emphysema, mild atelectasis, preexisting systemic disease (TB, sarcoidosis, mixed connective tissue disease, and CREST [calcinosis, Raynaud syndrome, esophageal dysmotility, sclerodactyly, telangiectasia] syndrome), postoperative and postradiation therapy changes, skeletal changes, and minimal and insignificant parenchymal findings (scarring, fibrosis, aspecific small isolated nodules, and small bullae). In 30 patients, these diagnoses were made in addition to PE, an alternative diagnosis, or an incidental finding.

Diagnostic and Therapeutic Consequences

In 11 patients (5.4%), CTPA abnormalities had diagnostic consequences (Fig 1), mostly bronchoscopy, thoracentesis, sputum culture, cardiac evaluation, or MRI scan. These diagnostic tests resulted in treatment or a change of treatment in five patients.

The start or change of therapy was a direct result of the CTPA findings in 10 patients (4.9%) (Fig 1, Table 1). The therapeutic consequences were initiation of antibiotics in seven patients, diuretics in two patients, and corticosteroids in the remaining patient. Of these 10 patients, the findings were an indirect consequence after a diagnostic step in five and a direct consequence of the CTPA in the other five.

Comparison Between Diagnoses at Baseline and 3-Month Follow-up

After 3 months, 13 patients (6.4%; 95% CI, 3.8%-11%) had died, but none of the deaths was believed to be from PE. In the remaining 190 patients, the initial diagnosis (PE, finding supporting an alternative diagnosis, or no abnormality) was unchanged in 187 (98%; 95% CI, 96%-99%) and had been adjusted by the treating physician in three (1.6%; 95% CI, 0.6%-4.2%). In one patient, the diagnosis of PE was changed to artifact after reevaluation by two different radiologists. Two diagnoses of tumor (newly found masses) were changed after puncture to inflammation secondary to a foreign body and scar tissue. None of the patients was evaluated for DVT or PE during follow-up.

This study demonstrates that in patients with suspected PE, CTPA can detect findings supporting an alternative diagnosis in 43%. However, two-thirds of these findings were already known or suspected before CTPA was performed. The findings supporting alternative diagnoses had therapeutic consequences in 5% of the patients. Incidental findings on CTPA, such as nodules or enlarged lymph nodes, resulted in further diagnostic steps in 8% of patients, with limited therapeutic consequences.

Several studies previously addressed the issue of possible alternative diagnoses in patients who underwent CT scanning for suspected PE. The proportion of found alternative diagnoses ranged from 25% to 52%4,5,12,1618 and is consistent with the current findings. Hall and colleagues4 found an alternative diagnosis in 33% of 589 patients and an incidental finding requiring follow-up in 24%, far outnumbering the rate of PE in their study, which was only 9%. A retrospective analysis of a large multicenter clinical management study on PE investigated the frequency of alternative diagnoses on CTPA in 512 consecutive patients.5 In 130 of 512 patients without PE (25%, 95% CI, 9.5%-18%), an alternative diagnosis was considered likely. However, whether these alternative diagnoses observed on CTPA were already identified before CT scanning and whether these findings were clinically significant in terms of therapeutic consequences were not assessed. To our knowledge, the current prospective study is the first to assess the proportion of findings supporting alternative diagnoses and the clinical impact in terms of diagnostic and therapeutic consequences. Furthermore, we systematically collected information on alternative diagnoses before CTPA, thus reducing the risk of bias by knowledge of the CTPA result. The majority of findings supporting alternative diagnoses were already known before CTPA and led to therapeutic actions in only 5% of the presenting patients, indicating that the findings supporting alternative diagnoses can be established in the majority of patients by the history, clinical presentation, laboratory results, and chest radiograph and placing the perceived additional value of CTPA for the diagnosis of PE over other imaging modalities (eg, ventilation/perfusion scintigraphy) in perspective.

Although guidelines do not recommend performing CTPA in the case of an unlikely clinical decision rule and a normal d-dimer test result, this advice often is not followed for several reasons.15,19,20 One of these may be that some clinicians hope that CTPA will help them to find an alternative diagnosis in a patient with a low likelihood of PE. In the current study, 8% of the CTPA scans showed an incidental finding requiring repeated imaging and, thus, exposure to radiation and contrast or an invasive procedure without life-saving consequence in terms of early detection of a malignancy. Together with the relatively low yield of previously unsuspected alternative diagnoses with therapeutic consequences, liberal use of CTPA with the aim to detect an alternative diagnosis in patients with a low clinical suspicion of PE in terms of net clinical benefit is at least questionable.

Some limitations of the present study merit consideration. First, the study was conducted at a single tertiary-care referral center, and results may not be generalizable to other settings. However, the prevalence of PE was similar to that of other studies in which clinical probability combined with the D-dimer test15 were used, and it is likely that the rate of incidental findings would be comparable if similar evaluation and CTPA protocols and equipment were used. Second, there may be significant variability between radiologists reporting. In the present study, an independent radiologist did not confirm the diagnosis on the CTPA in the majority of cases. Although all CTPA scans were assessed according to a prespecified protocol, it cannot be ruled out that some of the patients were misclassified as having PE, an alternative finding, or an incidental finding. However, this setup reflects routine clinical practice of the diagnostic process of suspected PE. Third, the moderate sample size may have led to the different findings in support of an alternative diagnosis being rather small. However, the 95% CIs of the main results were narrow; therefore, we believe it unlikely that a larger sample size would have led to a materially different conclusion. Fourth, we did not study the impact of CTPA on the confidence of physicians in the finding supporting an alternative diagnosis and consequential demands of the patients. It is intrinsically difficult to check validity of pretest therapeutic intentions because verification could be influenced by the test result itself. We can only speculate whether the CTPA in certain patients helped to convert suspicion into confirmation of an alternative diagnosis and its implications. Furthermore, the distinction we made between a liberal definition of findings supporting an alternative diagnosis (potentially explaining findings [group A]) and a strict definition (sufficiently explaining findings [group B]) is arbitrary. However, we believe that this distinction makes our interpretations a more accurate reflection of clinical practice and shows that there is a considerable group of patients in whom it is difficult to prove that the observed findings support an alternative diagnosis and explain the complaints. When we used either the liberal or the strict definition, the main findings did not change. Finally, it was not possible to obtain a standard reference test for every suggested finding supporting an alternative diagnosis. Because approximately 98% of the diagnoses at baseline did not change at 3-month follow-up, we conclude that this study is a valid reflection of clinical practice.

In conclusion, although CTPA yields findings supporting alternative diagnoses in a considerable proportion of patients with suspected PE, it results in a change or initiation of therapy in only 5% of the total population. Furthermore, incidental findings requiring diagnostic follow-up were found in 23 patients (11%). Hence, CTPA should be used primarily to find or exclude PE in patients in whom the clinical probability is high based on clinical decision rule and D-dimer test result and not to establish a finding supporting an alternative diagnosis.

Author contributions: Drs van Es and Beenen had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

Dr van Es: contributed to the study design, analyses, and writing of the manuscript.

Dr Douma: contributed to the study design, analyses, and writing of the manuscript.

Dr Schreuder: contributed to gathering the data and review of the manuscript.

Dr Middeldorp: contributed to the study design and supervision of the writing of the manuscript.

Dr Kamphuisen: contributed to the study design and supervision of the writing of the manuscript.

Dr Gerdes: contributed to the study design, analyses, and writing of the manuscript.

Dr Beenen: contributed to the study design, supervision of the data gathering, and writing of the manuscript.

Financial/nonfinancial disclosures: The authors have reported to CHEST that no potential conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.

CTPA

CT pulmonary angiography

PE

pulmonary embolism

Musset D, Parent F, Meyer G, et al; Evaluation du Scanner Spiralé dans l’Embolie Pulmonaire study group. Diagnostic strategy for patients with suspected pulmonary embolism: a prospective multicentre outcome study. Lancet. 2002;360(9349):1914-1920. [CrossRef] [PubMed]
 
Stein PD, Fowler SE, Goodman LR, et al; PIOPED II Investigators. Multidetector computed tomography for acute pulmonary embolism. N Engl J Med. 2006;354(22):2317-2327. [CrossRef] [PubMed]
 
Quiroz R, Kucher N, Zou KH, et al. Clinical validity of a negative computed tomography scan in patients with suspected pulmonary embolism: a systematic review. JAMA. 2005;293(16):2012-2017. [CrossRef] [PubMed]
 
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(21):1961-1965. [CrossRef] [PubMed]
 
van Strijen MJ, Bloem JL, de Monyé W, et al; Antelope-Study Group. Helical computed tomography and alternative diagnosis in patients with excluded pulmonary embolism. J Thromb Haemost. 2005;3(11):2449-2456. [CrossRef] [PubMed]
 
Faletra FF, D’Angeli I, Klersy C, et al. Estimates of lifetime attributable risk of cancer after a single radiation exposure from 64-slice computed tomographic coronary angiography. Heart. 2010;96(12):927-932. [CrossRef] [PubMed]
 
Einstein AJ, Henzlova MJ, Rajagopalan S. Estimating risk of cancer associated with radiation exposure from 64-slice computed tomography coronary angiography. JAMA. 2007;298(3):317-323. [CrossRef] [PubMed]
 
Brenner DJ, Hall EJ. Computed tomography—an increasing source of radiation exposure. N Engl J Med. 2007;357(22):2277-2284. [CrossRef] [PubMed]
 
Bach PB, Mirkin JN, Oliver TK, et al. Benefits and harms of CT screening for lung cancer: a systematic review. JAMA. 2012;307(22):2418-2429. [CrossRef] [PubMed]
 
MacMahon H, Austin JH, Gamsu G, et al; Fleischner Society. Guidelines for management of small pulmonary nodules detected on CT scans: a statement from the Fleischner Society. Radiology. 2005;237(2):395-400. [CrossRef] [PubMed]
 
van Strijen MJ, de Monyé W, Schiereck J, et al; Advances in New Technologies Evaluating the Localisation of Pulmonary Embolism Study Group. Single-detector helical computed tomography as the primary diagnostic test in suspected pulmonary embolism: a multicenter clinical management study of 510 patients. Ann Intern Med. 2003;138(4):307-314. [CrossRef] [PubMed]
 
Lin YT, Tsai IC, Tsai WL, et al. Comprehensive evaluation of CT pulmonary angiography for patients suspected of having pulmonary embolism. Int J Cardiovasc Imaging. 2010;26(suppl 1):111-120. [CrossRef] [PubMed]
 
Lamare G, Schorr A, Chan C. Chest radiographs can minimize the use of computed tomography of the chest when combined with screening scores for pulmonary embolism evaluation. Chest. 2012;142(4_MeetingAbstracts):853A. [CrossRef]
 
Wells PS, Anderson DR, Rodger M, et al. Derivation of a simple clinical model to categorize patients probability of pulmonary embolism: increasing the models utility with the SimpliRED D-dimer. Thromb Haemost. 2000;83(3):416-420. [PubMed]
 
van Belle A, Büller HR, Huisman MV, et al; Christopher Study Investigators. Effectiveness of managing suspected pulmonary embolism using an algorithm combining clinical probability, D-dimer testing, and computed tomography. JAMA. 2006;295(2):172-179. [CrossRef] [PubMed]
 
Lombard J, Bhatia R, Sala E. Spiral computed tomographic pulmonary angiography for investigating suspected pulmonary embolism: clinical outcomes. Can Assoc Radiol J. 2003;54(3):147-151. [PubMed]
 
Kim KI, Müller NL, Mayo JR. Clinically suspected pulmonary embolism: utility of spiral CT. Radiology. 1999;210(3):693-697. [CrossRef] [PubMed]
 
van Rossum AB, Treurniet FE, Kieft GJ, Smith SJ, Schepers-Bok R. Role of spiral volumetric computed tomographic scanning in the assessment of patients with clinical suspicion of pulmonary embolism and an abnormal ventilation/perfusion lung scan. Thorax. 1996;51(1):23-28. [CrossRef] [PubMed]
 
Gibson NS, Douma RA, Squizzato A, Söhne M, Büller HR, Gerdes VE. Application of a decision rule and a D-dimer assay in the diagnosis of pulmonary embolism. Thromb Haemost. 2010;103(4):849-854. [CrossRef] [PubMed]
 
Roy PM, Meyer G, Vielle B, et al; EMDEPU Study Group. Appropriateness of diagnostic management and outcomes of suspected pulmonary embolism. Ann Intern Med. 2006;144(3):157-164. [CrossRef] [PubMed]
 

Figures

Figure Jump LinkFigure 1. Flowchart of findings supporting an alternative diagnosis and the subsequent results in diagnostic and therapeutic consequences.Grahic Jump Location

Tables

Table Graphic Jump Location
Table 1 —Prevalence of Radiographic Findings, Findings Supporting an Alternative Diagnosis, and Incidental Findings in the Diagnostic Workup of PE in 203 CTPA Scans

Data are presented as No. (%, 95% CI). CTPA = CT pulmonary angiography; PE = pulmonary embolism.

a 

Group A: findings supporting an alternative diagnosis that potentially explained the signs and symptoms of the patient.

b 

Group B: findings supporting an alternative diagnosis that sufficiently explained the signs and symptoms of the patient, as was concluded by the treating physician.

c 

Patients may be classified as having more than one outcome (PE, alternative diagnosis, incidental finding, etc).

Table Graphic Jump Location
Table 2 —Clinical Characteristics

Data are presented as No. (%) unless otherwise indicated.

References

Musset D, Parent F, Meyer G, et al; Evaluation du Scanner Spiralé dans l’Embolie Pulmonaire study group. Diagnostic strategy for patients with suspected pulmonary embolism: a prospective multicentre outcome study. Lancet. 2002;360(9349):1914-1920. [CrossRef] [PubMed]
 
Stein PD, Fowler SE, Goodman LR, et al; PIOPED II Investigators. Multidetector computed tomography for acute pulmonary embolism. N Engl J Med. 2006;354(22):2317-2327. [CrossRef] [PubMed]
 
Quiroz R, Kucher N, Zou KH, et al. Clinical validity of a negative computed tomography scan in patients with suspected pulmonary embolism: a systematic review. JAMA. 2005;293(16):2012-2017. [CrossRef] [PubMed]
 
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(21):1961-1965. [CrossRef] [PubMed]
 
van Strijen MJ, Bloem JL, de Monyé W, et al; Antelope-Study Group. Helical computed tomography and alternative diagnosis in patients with excluded pulmonary embolism. J Thromb Haemost. 2005;3(11):2449-2456. [CrossRef] [PubMed]
 
Faletra FF, D’Angeli I, Klersy C, et al. Estimates of lifetime attributable risk of cancer after a single radiation exposure from 64-slice computed tomographic coronary angiography. Heart. 2010;96(12):927-932. [CrossRef] [PubMed]
 
Einstein AJ, Henzlova MJ, Rajagopalan S. Estimating risk of cancer associated with radiation exposure from 64-slice computed tomography coronary angiography. JAMA. 2007;298(3):317-323. [CrossRef] [PubMed]
 
Brenner DJ, Hall EJ. Computed tomography—an increasing source of radiation exposure. N Engl J Med. 2007;357(22):2277-2284. [CrossRef] [PubMed]
 
Bach PB, Mirkin JN, Oliver TK, et al. Benefits and harms of CT screening for lung cancer: a systematic review. JAMA. 2012;307(22):2418-2429. [CrossRef] [PubMed]
 
MacMahon H, Austin JH, Gamsu G, et al; Fleischner Society. Guidelines for management of small pulmonary nodules detected on CT scans: a statement from the Fleischner Society. Radiology. 2005;237(2):395-400. [CrossRef] [PubMed]
 
van Strijen MJ, de Monyé W, Schiereck J, et al; Advances in New Technologies Evaluating the Localisation of Pulmonary Embolism Study Group. Single-detector helical computed tomography as the primary diagnostic test in suspected pulmonary embolism: a multicenter clinical management study of 510 patients. Ann Intern Med. 2003;138(4):307-314. [CrossRef] [PubMed]
 
Lin YT, Tsai IC, Tsai WL, et al. Comprehensive evaluation of CT pulmonary angiography for patients suspected of having pulmonary embolism. Int J Cardiovasc Imaging. 2010;26(suppl 1):111-120. [CrossRef] [PubMed]
 
Lamare G, Schorr A, Chan C. Chest radiographs can minimize the use of computed tomography of the chest when combined with screening scores for pulmonary embolism evaluation. Chest. 2012;142(4_MeetingAbstracts):853A. [CrossRef]
 
Wells PS, Anderson DR, Rodger M, et al. Derivation of a simple clinical model to categorize patients probability of pulmonary embolism: increasing the models utility with the SimpliRED D-dimer. Thromb Haemost. 2000;83(3):416-420. [PubMed]
 
van Belle A, Büller HR, Huisman MV, et al; Christopher Study Investigators. Effectiveness of managing suspected pulmonary embolism using an algorithm combining clinical probability, D-dimer testing, and computed tomography. JAMA. 2006;295(2):172-179. [CrossRef] [PubMed]
 
Lombard J, Bhatia R, Sala E. Spiral computed tomographic pulmonary angiography for investigating suspected pulmonary embolism: clinical outcomes. Can Assoc Radiol J. 2003;54(3):147-151. [PubMed]
 
Kim KI, Müller NL, Mayo JR. Clinically suspected pulmonary embolism: utility of spiral CT. Radiology. 1999;210(3):693-697. [CrossRef] [PubMed]
 
van Rossum AB, Treurniet FE, Kieft GJ, Smith SJ, Schepers-Bok R. Role of spiral volumetric computed tomographic scanning in the assessment of patients with clinical suspicion of pulmonary embolism and an abnormal ventilation/perfusion lung scan. Thorax. 1996;51(1):23-28. [CrossRef] [PubMed]
 
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    Print ISSN: 0012-3692
    Online ISSN: 1931-3543