HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Stein, P. D. Articles by Buckley, J. D. Search for Related Content PubMed PubMed Citation Articles by Stein, P. D. Articles by Buckley, J. D.

Diagnostic Pathways in Acute Pulmonary Embolism: Recommendations of the PIOPED II Investigators¹

¹ From the Department of Research, St. Joseph Mercy Oakland Hospital, 44405 Woodward Ave, Pontiac, MI 48341-5023 (P.D.S.); Department of Medicine, Wayne State University, Detroit, Mich (P.D.S.); Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Mo (P.K.W.); Departments of Medicine (J.G.W.) and Surgery (T.W.F.), University of Michigan, Ann Arbor, Mich; Department of Medicine, Duke University, Durham, NC (V.F.T.); Office of the Dean, Weill Cornell Medical College, New York, NY, and Office of the Executive Vice President, Methodist Hospital, Houston, Tex (H.D.S.); Department of Radiology, Weill Cornell Medical College, New York, NY (T.A.S.); Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Mass (D.A.Q., C.A.H.); Department of Medicine, Emory University, Atlanta, Ga (K.V.L.); Department of Medicine, University of Calgary, Calgary, Alberta, Canada (R.D.H.); Department of Radiology, Michigan State University, East Lansing, Mich (A.G.); Department of Radiology, Medical College of Wisconsin, Milwaukee, Wis (L.R.G.); the Biostatistics Center, Department of Epidemiology and Biostatistics, George Washington University, Rockville, Md (S.E.F.); and Department of Medicine, Henry Ford Hospital, Detroit, Mich (J.D.B.). Received June 5, 2006; final version accepted June 8. Supported by grants HL63899, HL63928, HL63931, HL063932, HL63940, HL63941, HL63942, HL63981, HL63982, and HL67453 from the U.S. Department of Health and Human Services, Public Health Services, National Heart, Lung, and Blood Institute, Bethesda, Maryland. Address correspondence to P.D.S. (e-mail: steinp{at}trinity-health.org).

Editor's note: A similar version of this editorial was published in the December 2006 issue of the American Journal of Medicine (^©American Journal of Medicine, 2006). It is being published here, with permission, to also reach the readers of Radiology.–Anthony V. Proto, MD, Editor

The choice of diagnostic tests depends on the clinical probability of pulmonary embolism, condition of the patient, availability of diagnostic tests, risks of iodinated contrast material, radiation exposure, and cost. Recommendations can now be formulated on the basis of the results of the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) II trial (1) and other studies (2–4), albeit with continued reliance on the physician's judgment. The following recommendations include both evidence-based recommendations and opinions based on information available at this time. Both are subject to revision as further data become available. Information related to radiation exposure (5–12), charges for tests, and positive predictive values of clinical probability assessments (2, 13–19) are shown in Tables 1–3.

	CLINICAL ASSESSMENT

TOP INTRODUCTION CLINICAL ASSESSMENT PATIENTS WITH LOW PROBABILITY... PATIENTS WITH MODERATE... PATIENTS WITH HIGH PROBABILITY... OPTIONAL PATHWAYS FOR ALL... PATIENTS WITH ALLERGY TO... PATIENTS WITH IMPAIRED RENAL... WOMEN OF REPRODUCTIVE AGE PREGNANT PATIENTS PATIENTS IN EXTREMIS References

Recommendations for Clinical Assessment
1. Clinical assessment should be made prior to imaging.

2. Clinical assessment should be made with an objective method.

	PATIENTS WITH LOW PROBABILITY CLINICAL ASSESSMENT

TOP INTRODUCTION CLINICAL ASSESSMENT PATIENTS WITH LOW PROBABILITY... PATIENTS WITH MODERATE... PATIENTS WITH HIGH PROBABILITY... OPTIONAL PATHWAYS FOR ALL... PATIENTS WITH ALLERGY TO... PATIENTS WITH IMPAIRED RENAL... WOMEN OF REPRODUCTIVE AGE PREGNANT PATIENTS PATIENTS IN EXTREMIS References

 
The quantitative rapid ELISA, with a sensitivity of 95%, in general has shown the most clinically useful values among the various D-dimer assays (20). When the quantitative rapid ELISA is used in combination with a low probability objective clinical assessment that ranges from 4% to 15% (2,13–17,19) (Table 3; Figs 1, 2), the posttest probability of pulmonary embolism ranges from 0.7% to 2% with a normal D-dimer rapid ELISA result (20,21). No further testing is required if the D-dimer is normal in a patient with a low probability clinical assessment. Additional testing with venous US or gadolinium-enhanced magnetic resonance (MR) venography (22) is optional.

View larger version (31K): [in this window] [in a new window] [Download PPT slide]   Figure 1: Flowchart shows use of quantitative rapid D-dimer ELISA in combination with clinical assessment. If clinical assessment indicates low or moderate probability and the D-dimer rapid ELISA result is negative, pulmonary embolism would be excluded. If clinical assessment indicates high probability, further testing is necessary irrespective of the results of D-dimer testing.

View larger version (40K): [in this window] [in a new window] [Download PPT slide]   Figure 2: Flowchart for diagnosis with contrast-enhanced multidetector CT angiography or CT angiography and venography (specifically, contrast-enhanced multidetector CT venous phase imaging of veins of lower extremities) after D-dimer testing in combination with low probability clinical assessment. NPV = negative predictive value, PPV = positive predictive value.

Radiation exposure can be reduced by omitting the iliac veins and inferior vena cava in the CT venogram. Among 105 patients who showed thrombi at CT venography, the iliac veins or the inferior vena cava showed thrombi in the absence of femoral or popliteal vein thrombi in only three (3%) (1).

In PIOPED II, among patients with a low probability clinical assessment, if CT angiography results were negative, pulmonary embolism was present in 4%, and if CT angiography and venography results were negative, pulmonary embolism was present in 3% (1). In outcome studies of untreated patients with normal CT angiography results and clinical assessment findings that ranged from low probability to "likely," 1.3% of patients had venous thromboembolism and 1.5% of patients would have had pulmonary embolism or deep venous thrombosis at 3-month follow-up (3,4).

If CT angiography results were positive in a patient with a low probability clinical assessment, pulmonary embolism was present in 58%; with a positive CT angiogram or CT venogram, pulmonary embolism was present in 57% (1). However, if CT angiography showed pulmonary embolism in a main or lobar pulmonary artery, pulmonary embolism was present in 97% (1). If the largest vessel showing pulmonary embolism was in a segmental branch, pulmonary embolism was present in 68% of patients, and if the largest vessel showing pulmonary embolism was in a subsegmental branch, pulmonary embolism was present in 25% of patients, but data are sparse in the subsegmental group (1).

Recommendations for Patients with Low Probability Clinical Assessment
1. Perform a D-dimer rapid ELISA.

2. No further testing is required if D-dimer is normal.

3. If D-dimer result is positive, CT angiography and venography is recommended by most (77%) PIOPED II investigators.

4. CT venography of only the femoral and popliteal veins is recommended to reduce radiation exposure.

5. If CT angiography or CT angiography and venography results are negative, treatment is unnecessary.

6. With main or lobar pulmonary emboli at CT angiography, treatment is indicated.

7. With segmental or subsegmental pulmonary emboli, the certainty of the CT diagnosis should be reassessed.

8. CT angiography or CT angiography and venography should be repeated if image quality is poor.

9. In patients with segmental or subsegmental pulmonary emboli, pulmonary scintigraphy, a single venous US examination in those evaluated with CT angiography only, serial venous US examinations (13,23), and pulmonary digital subtraction angiography are optional.

	PATIENTS WITH MODERATE PROBABILITY CLINICAL ASSESSMENT

TOP INTRODUCTION CLINICAL ASSESSMENT PATIENTS WITH LOW PROBABILITY... PATIENTS WITH MODERATE... PATIENTS WITH HIGH PROBABILITY... OPTIONAL PATHWAYS FOR ALL... PATIENTS WITH ALLERGY TO... PATIENTS WITH IMPAIRED RENAL... WOMEN OF REPRODUCTIVE AGE PREGNANT PATIENTS PATIENTS IN EXTREMIS References

 
Among patients with objectively measured moderate clinical probabilities of pulmonary embolism, 29%–38% were shown to have pulmonary embolism (2,14–17,19) (Fig 3). The posttest probability of pulmonary embolism with a 30% clinical probability of pulmonary embolism is 5% with a normal rapid ELISA result (20,21).

View larger version (32K): [in this window] [in a new window] [Download PPT slide]   Figure 3: Flowchart for diagnosis with CT angiography or CT angiography and venography after D-dimer testing in combination with moderate probability clinical assessment. NPV = negative predictive value, PPV = positive predictive value.

If CT angiography results were positive in a patient with a moderate probability clinical assessment, pulmonary embolism was present in 92%; with a positive CT angiogram or CT venogram, pulmonary embolism was present in 90% (1). The predictive values with lobar, segmental, and subsegmental pulmonary emboli and recommendations for further imaging are as described in the section on low probability clinical assessment.

Recommendations for Patients with Moderate Probability Clinical Assessment
1. We recommend a D-dimer rapid ELISA.

2. If the D-dimer rapid ELISA result is negative, no further testing is necessary, but a venous US or MR venography examination is optional.

3. If the D-dimer result is positive, CT angiography and venography is recommended by most (77%) PIOPED II investigators.

4. Treatment with anticoagulants while awaiting the outcome of diagnostic tests may be appropriate, particularly if the tests cannot be performed immediately (24).

5. If either CT angiography or CT angiography and venography results are negative, no treatment is necessary, but a venous US examination is recommended for those with a negative CT angiogram alone.

6. If either CT angiography or CT angiography and venography results are positive, treatment is recommended.

7. With segmental or subsegmental pulmonary emboli, the certainty of the CT diagnosis should be reassessed and options should be followed according to recommendations for patients with a low probability clinical assessment.

	PATIENTS WITH HIGH PROBABILITY CLINICAL ASSESSMENT

TOP INTRODUCTION CLINICAL ASSESSMENT PATIENTS WITH LOW PROBABILITY... PATIENTS WITH MODERATE... PATIENTS WITH HIGH PROBABILITY... OPTIONAL PATHWAYS FOR ALL... PATIENTS WITH ALLERGY TO... PATIENTS WITH IMPAIRED RENAL... WOMEN OF REPRODUCTIVE AGE PREGNANT PATIENTS PATIENTS IN EXTREMIS References

 
A D-dimer test is not helpful because a negative D-dimer result does not exclude pulmonary embolism in more than 15% of patients with a high probability clinical assessment (20,21).

If results of either CT angiography alone or the CT angiography and venography combination were positive in a patient with a high probability clinical assessment, pulmonary embolism was present in 96% in PIOPED II (1) (Fig 4). If CT angiography results were negative in a patient with a high probability assessment, pulmonary embolism was present in 40%, and if CT angiography and venography results were negative, pulmonary embolism was present in 18% (1). When a ventilation-perfusion lung scan is considered for further testing, or when a perfusion lung scan alone is considered if the chest radiograph is normal or nearly normal (25), the proportion of patients with a nondiagnostic pulmonary scintigram is lower with a normal chest radiograph than with an abnormal chest radiograph (26,27) and has been reported to be only 9% (27).

View larger version (29K): [in this window] [in a new window] [Download PPT slide]   Figure 4: Flowchart for diagnosis with CT angiography or CT angiography and venography in combination with high probability clinical assessment. NPV = negative predictive value, PPV = positive predictive value.

2. Treat the patient with anticoagulants while awaiting the outcome of diagnostic tests (24).

3. Most (77%) PIOPED II investigators recommend CT angiography and venography.

4. If CT angiography results are negative and CT angiography and venography was not performed or was technically inadequate, a venous US or MR venography examination is recommended.

5. If either CT angiography or CT angiography and venography results are negative, other options include serial venous US examinations, pulmonary digital subtraction angiography, and pulmonary scintigraphy.

6. If either CT angiography or CT angiography and venography results are positive, treatment is recommended.

	OPTIONAL PATHWAYS FOR ALL PATIENTS

TOP INTRODUCTION CLINICAL ASSESSMENT PATIENTS WITH LOW PROBABILITY... PATIENTS WITH MODERATE... PATIENTS WITH HIGH PROBABILITY... OPTIONAL PATHWAYS FOR ALL... PATIENTS WITH ALLERGY TO... PATIENTS WITH IMPAIRED RENAL... WOMEN OF REPRODUCTIVE AGE PREGNANT PATIENTS PATIENTS IN EXTREMIS References

 
Venous US depicts deep venous thrombosis in 13%–15% of patients suspected of having pulmonary embolism (28,29) and in 29% of patients with proved pulmonary embolism (29), thereby allowing treatment with no further obligatory testing.

Recommendation for Optional Pathways
A venous US examination prior to imaging with CT angiography or CT angiography and venography is optional and may guide treatment if results are positive.

	PATIENTS WITH ALLERGY TO IODINATED CONTRAST MATERIAL

TOP INTRODUCTION CLINICAL ASSESSMENT PATIENTS WITH LOW PROBABILITY... PATIENTS WITH MODERATE... PATIENTS WITH HIGH PROBABILITY... OPTIONAL PATHWAYS FOR ALL... PATIENTS WITH ALLERGY TO... PATIENTS WITH IMPAIRED RENAL... WOMEN OF REPRODUCTIVE AGE PREGNANT PATIENTS PATIENTS IN EXTREMIS References

 
If clinical assessment and D-dimer testing fail to exclude pulmonary embolism, venous US results may be positive and guide therapy. Patients with mild to moderate iodine allergies may be pretreated with steroids and then imaged with CT. With severe iodine allergy, pulmonary scintigraphy may be a useful alternative. A low probability ventilation-perfusion scan result combined with a low probability clinical assessment showed pulmonary embolism in only 4% of patients (18). A high probability ventilation-perfusion scan result combined with a high probability clinical assessment showed pulmonary embolism in 96% of patients (18). With other combinations, pulmonary embolism was present in 16%–88% of patients and further evaluation was needed. Further evaluation may include serial venous US examinations (13,23) or CT angiography enhanced with 0.3–0.4 mmol gadolinium per kilogram of body weight (30). Preliminary investigations suggest that gadolinium-enhanced MR imaging may be useful (31–34).

Recommendations for Patients with Allergy to Iodinated Contrast Material
1. D-dimer testing with clinical assessment is recommended to exclude pulmonary embolism.

2. Patients with mild iodine allergies may be treated with steroids prior to CT imaging.

3. Venous US and pulmonary scintigraphy are recommended as alternative diagnostic tests in patients with severe iodine allergy.

4. Serial venous US examinations and gadolinium-enhanced CT angiography are options.

	PATIENTS WITH IMPAIRED RENAL FUNCTION

TOP INTRODUCTION CLINICAL ASSESSMENT PATIENTS WITH LOW PROBABILITY... PATIENTS WITH MODERATE... PATIENTS WITH HIGH PROBABILITY... OPTIONAL PATHWAYS FOR ALL... PATIENTS WITH ALLERGY TO... PATIENTS WITH IMPAIRED RENAL... WOMEN OF REPRODUCTIVE AGE PREGNANT PATIENTS PATIENTS IN EXTREMIS References

 
In PIOPED II, only one of 824 patients who underwent CT angiography (0.1%) developed renal failure (1). Nonionic contrast material was used (1). Patients with abnormal serum creatinine levels were excluded. If the creatinine clearance is only somewhat elevated, whether to proceed with CT imaging depends on clinical judgment. Nonionic contrast material appears to be less nephrotoxic (35) and generally better tolerated (36) than ionic contrast material, although some investigators have reported no difference in nephrotoxicity (37). Prophylactic hydration with sodium bicarbonate before contrast material exposure reduces the risks of renal dysfunction in patients with renal insufficiency and has been reported to be more effective than hydration with sodium chloride (38). An isotonic solution of sodium bicarbonate 3 mL/kg/h for 1 hour before and 1 mL/kg/h for 6 hours after the administration of contrast material has been recommended (38,39).

Nonsteroidal antiinflammatory drugs and dipyridamole were discontinued in PIOPED II. They should be discontinued as early as possible before the administration of contrast material (40). Metformin also should be discontinued before the injection of contrast material, because if contrast material–induced renal failure occurs, metformin accumulation in body tissues could cause lactic acidosis (41). Metformin, however, does not cause renal failure (41). In emergency or urgent situations, if renal function is normal, the study may proceed with little risk (41). If renal function is abnormal or unknown, metformin should be discontinued, and hydration, as well as other precautions listed above, should be taken (41). Therapy with metformin can be resumed when renal function has been shown to be normal (40,41). Results with angiotensin-converting enzyme inhibitors have been equivocal (40).

Recommendations for Patients with Impaired Renal Function
1. D-dimer testing with clinical assessment is recommended to exclude pulmonary embolism.

2. Venous US is recommended, and, if results are positive, treatment is indicated.

3. Pulmonary scintigraphy is recommended if venous US results are negative.

4. Serial venous US examinations are an option.

	WOMEN OF REPRODUCTIVE AGE

TOP INTRODUCTION CLINICAL ASSESSMENT PATIENTS WITH LOW PROBABILITY... PATIENTS WITH MODERATE... PATIENTS WITH HIGH PROBABILITY... OPTIONAL PATHWAYS FOR ALL... PATIENTS WITH ALLERGY TO... PATIENTS WITH IMPAIRED RENAL... WOMEN OF REPRODUCTIVE AGE PREGNANT PATIENTS PATIENTS IN EXTREMIS References

 
Female breast radiation is a concern, but the risk of death from undiagnosed pulmonary embolism far exceeds the risk of radiation-induced malignancy. The absorbed dose to the breast with CT angiography has been calculated as 10–50 mGy (42–44). The absorbed dose to the breast with a perfusion lung scan has been estimated to be 0.28 mGy (42). The absorbed dose to the breast with standard two-view mammography is 3 mGy (43).

The use of pulmonary scintigraphy would minimize breast irradiation. In PIOPED, a ventilation-perfusion scan in patients with a normal chest radiograph was diagnostic (high probability or normal/nearly normal) in 52% of patients suspected of having pulmonary embolism (26). More recently, a ventilation-perfusion scan was shown to be diagnostic in 91% of patients suspected of having pulmonary embolism and with a normal chest radiograph (27).

Recommendations for Women of Reproductive Age
1. If D-dimer rapid ELISA results are positive, venous US as the next diagnostic test is optional.

2. Pulmonary scintigraphy is recommended by 31% of PIOPED II investigators as the next imaging test, but most (69%) recommend CT angiography.

3. CT angiography with venous US is an acceptable alternative.

4. If a CT venogram is deemed necessary, it is advisable to start at the acetabulum to reduce gonadal irradiation.

	PREGNANT PATIENTS

TOP INTRODUCTION CLINICAL ASSESSMENT PATIENTS WITH LOW PROBABILITY... PATIENTS WITH MODERATE... PATIENTS WITH HIGH PROBABILITY... OPTIONAL PATHWAYS FOR ALL... PATIENTS WITH ALLERGY TO... PATIENTS WITH IMPAIRED RENAL... WOMEN OF REPRODUCTIVE AGE PREGNANT PATIENTS PATIENTS IN EXTREMIS References

 
In pregnant women, D-dimer testing may be useful even though results may be positive owing to the pregnancy (45). Venous US depicts deep venous thrombosis in 13%–15% of patients suspected of having pulmonary embolism (28,29) and in 29% of patients with proved pulmonary embolism (29), eliminating the need for radiographic imaging. If radiographic imaging is necessary, some have recommended (46) or used (47) CT angiography rather than ventilation/perfusion lung scans. MR imaging requires further validation (31–34). However, adequate and well-controlled studies of gadopentetate dimeglumine have not been conducted in pregnant women (48). It is not known to what extent it is excreted in human milk (48).

Some indicate that the radiation dose to the fetus from 16-section CT angiography (0.24–0.47 mGy at 0 months and 0.61–0.66 mGy at 3 months) is of the same magnitude as that from a ventilation/perfusion scan (0.25–0.36 mGy at 0 months and 0.31–0.32 mGy at 3 months) or a perfusion scan alone (0.21 mGy at 0 months and 0.30 mGy at 3 months) (49). Others indicate that the absorbed dose to the fetus is less with CT angiography than with a perfusion scan (0.01 mGy vs 0.12 mGy) (42).

Recommendations for Pregnant Patients
1. D-dimer testing with clinical assessment should be performed.

2. If D-dimer results are positive, venous US is recommended before imaging tests with ionizing radiation are performed.

3. Most (69%) PIOPED II investigators recommend pulmonary scintigraphy, and 31% recommend CT angiography.

	PATIENTS IN EXTREMIS

TOP INTRODUCTION CLINICAL ASSESSMENT PATIENTS WITH LOW PROBABILITY... PATIENTS WITH MODERATE... PATIENTS WITH HIGH PROBABILITY... OPTIONAL PATHWAYS FOR ALL... PATIENTS WITH ALLERGY TO... PATIENTS WITH IMPAIRED RENAL... WOMEN OF REPRODUCTIVE AGE PREGNANT PATIENTS PATIENTS IN EXTREMIS References

 
The sensitivity of transthoracic echocardiography for right ventricular enlargement or dysfunction in patients with massive pulmonary embolism or unstable patients, combining data from three case series, was 33 of 33 (100%) (50–52). If any two of three assessments (high clinical probability, echocardiography, US) were positive, the sensitivity for massive pulmonary embolism was 33 of 34 (97%), and the negative predictive value was 98% (53).

Recommendations for Patients in Extremis
1. Bedside echocardiography in combination with bedside leg US are recommended as rapidly performable bedside tests.

2. Right ventricular enlargement or poor right ventricular function, in a proper clinical setting, can be interpreted as resulting from pulmonary embolism.

3. A positive venous US result in the appropriate clinical setting also indicates pulmonary embolism.

4. A portable perfusion scan is recommended by 38% of the PIOPED II investigators.

5. Immediate transfer to an interventional catheterization laboratory is recommended by 38% of the PIOPED II investigators.

6. A combination of negative bedside echocardiographic and venous US results indicates the need for CT angiography if it is feasible.

7. When the patient's condition stabilizes, appropriate imaging studies should be performed.

In conclusion, the PIOPED II investigators recommend stratification of all patients suspected of having pulmonary embolism according to an objective probability assessment. A negative D-dimer rapid ELISA result with a low or moderate probability clinical assessment can safely exclude pulmonary embolism. If pulmonary embolism is not excluded, CT angiography and venography is recommended by 77% of the PIOPED II investigators, although CT angiography alone is an option. In patients with discordant findings at clinical assessment and CT imaging, further evaluation depends on clinical judgment. In pregnant women, ventilation/perfusion scans are recommended by 69% of PIOPED II investigators as the first imaging test.

	References

TOP INTRODUCTION CLINICAL ASSESSMENT PATIENTS WITH LOW PROBABILITY... PATIENTS WITH MODERATE... PATIENTS WITH HIGH PROBABILITY... OPTIONAL PATHWAYS FOR ALL... PATIENTS WITH ALLERGY TO... PATIENTS WITH IMPAIRED RENAL... WOMEN OF REPRODUCTIVE AGE PREGNANT PATIENTS PATIENTS IN EXTREMIS References

 

1. Stein PD, Fowler SE, Goodman LR, et al. Multidetector computed tomography for acute pulmonary embolism. N Engl J Med 2006;354(22):2317–2327.[Abstract/Free Full Text]
2. Wells PS, Anderson DR, Rodger M, et al. 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 2001;135(2):98–107.[Abstract/Free Full Text]
3. Perrier A, Roy PM, Sanchez O, et al. Multidetector-row computed tomography in suspected pulmonary embolism. N Engl J Med 2005;352(17):1760–1768.[Abstract/Free Full Text]
4. van Belle A, Buller HR, Huisman MV, et al. Effectiveness of managing suspected pulmonary embolism using an algorithm combining clinical probability, D-dimer testing, and computed tomography. JAMA 2006;295(2):172–179.[Abstract/Free Full Text]
5. Robinson A. Radiation protection and patient doses in diagnostic radiology. In: Grainger RG, Allison D, eds. Grainger & Allison's diagnostic radiology: a textbook of medical imaging. 3rd ed. New York, NY: Churchill Livingstone, 1997; 169–183.
6. Kuiper JW, Geleijns J, Matheijssen NA, Teeuwisse W, Pattynama PM. Radiation exposure of multi-row detector spiral computed tomography of the pulmonary arteries: comparison with digital subtraction pulmonary angiography. Eur Radiol 2003;13(7):1496–1500.[CrossRef][Medline]
7. O'Neill J, Murchison JT, Wright L, Williams J. Effect of the introduction of helical CT on radiation dose in the investigation of pulmonary embolism. Br J Radiol 2005;78(925):46–50.[Abstract/Free Full Text]
8. Mayo JR, Aldrich J, Muller NL. Radiation exposure at chest CT: a statement of the Fleischner society. Radiology 2003;228(1):15–21.[Abstract/Free Full Text]
9. Resten A, Mausoleo F, Valero M, Musset D. Comparison of doses for pulmonary embolism detection with helical CT and pulmonary angiography. Eur Radiol 2003;13(7):1515–1521.[CrossRef][Medline]
10. Wittram C, Liu B, Callahan RJ, Hales C, Quinn DA, Stein PD. An estimate of the radiation dose received per patient for the investigation of pulmonary venous thromboembolism based on the PIOPED II data (abstr). In: Radiological Society of North America Scientific Assembly and Annual Meeting Program. Oak Brook, Ill: Radiological Society of North America, 2005; 464.
11. Huda W, Sourkes AM. Radiation doses from chest x-rays in Manitoba (1979 and 1987). Radiat Prot Dosimetry 1989;28:303–308.[Abstract]
12. 1990 Recommendations of the International Commission on Radiological Protection. Ann ICRP 1991;21(1-3):1–201.[Medline]
13. Wells PS, Ginsberg JS, Anderson DR, et al. Use of a clinical model for safe management of patients with suspected pulmonary embolism. Ann Intern Med 1998;129(12):997–1005.[Abstract/Free Full Text]
14. Sanson BJ, Lijmer JG, Mac Gillavry MR, Turkstra F, Prins MH, Buller HR. Comparison of a clinical probability estimate and two clinical models in patients with suspected pulmonary embolism. ANTELOPE Study Group. Thromb Haemost 2000;83(2):199–203.[Medline]
15. 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.[Medline]
16. Chagnon I, Bounameaux H, Aujesky D, et al. Comparison of two clinical prediction rules and implicit assessment among patients with suspected pulmonary embolism. Am J Med 2002;113(4):269–275.[CrossRef][Medline]
17. Wicki J, Perneger TV, Junod AF, Bounameaux H, Perrier A. Assessing clinical probability of pulmonary embolism in the emergency ward: a simple score. Arch Intern Med 2001;161(1):92–97.[Abstract/Free Full Text]
18. Value of the ventilation/perfusion scan in acute pulmonary embolism. Results of the prospective investigation of pulmonary embolism diagnosis (PIOPED). The PIOPED Investigators. JAMA 1990;263(20):2753–2759.[Abstract]
19. Le Gal G, Righini M, Roy PM, et al. Prediction of pulmonary embolism in the emergency department: the revised Geneva score. Ann Intern Med 2006;144(3):165–171.[Abstract/Free Full Text]
20. Stein PD, Hull RD, Patel KC, et al. D-dimer for the exclusion of deep venous thrombosis and acute pulmonary embolism: a systematic review. Ann Intern Med 2004;140(8):589–602.[Abstract/Free Full Text]
21. Sox HC. Commentary. Ann Intern Med 2004;140:602.
22. Sostman HD. MRA for diagnosis of venous thromboembolism. Q J Nucl Med 2001;45(4):311–323.[Medline]
23. Stein PD, Hull RD, Pineo G. Strategy that includes serial noninvasive leg tests for diagnosis of thromboembolic disease in patients with suspected acute pulmonary embolism based on data from PIOPED. Prospective Investigation of Pulmonary Embolism Diagnosis. Arch Intern Med 1995;155(19):2101–2104.[Abstract]
24. Buller HR, Agnelli G, Hull RD, Hyers TM, Prins MH, Raskob GE. Antithrombotic therapy for venous thromboembolic disease: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy. Chest 2004;126(3 suppl):401S–428S. [Published correction appears in Chest 2005;127(1):416.]
25. Stein PD, Terrin ML, Gottschalk A, Alavi A, Henry JW. Value of ventilation/perfusion scans compared to perfusion scans alone in acute pulmonary embolism. Am J Cardiol 1992;69(14):1239–1241.[CrossRef][Medline]
26. Stein PD, Alavi A, Gottschalk A, et al. Usefulness of non-invasive diagnostic tools for diagnosis of acute pulmonary embolism in patients with a normal chest radiograph. Am J Cardiol 1991;67(13):1117–1120.[CrossRef][Medline]
27. Forbes KP, Reid JH, Murchison JT. Do preliminary chest X-ray findings define the optimum role of pulmonary scintigraphy in suspected pulmonary embolism? Clin Radiol 2001;56(5):397–400.[CrossRef][Medline]
28. Perrier A, Roy PM, Aujesky D, et al. Diagnosing pulmonary embolism in outpatients with clinical assessment, D-dimer measurement, venous ultrasound, and helical computed tomography: a multicenter management study. Am J Med 2004;116(5):291–299.[CrossRef][Medline]
29. Turkstra F, Kuijer PM, van Beek EJ, Brandjes DP, ten Cate JW, Buller HR. Diagnostic utility of ultrasonography of leg veins in patients suspected of having pulmonary embolism. Ann Intern Med 1997;126(10):775–781.[Abstract/Free Full Text]
30. Remy-Jardin M, Bahepar J, Lafitte JJ, et al. Multi-detector row CT angiography of pulmonary circulation with gadolinium-based contrast agents: prospective evaluation in 60 patients. Radiology 2006;238(3):1022–1035.[Abstract/Free Full Text]
31. Stein PD, Woodard PK, Hull RD, et al. Gadolinium enhanced magnetic resonance angiography for detection of acute pulmonary embolism: an in depth review. Chest 2003;124(6):2324–2328.
32. Meaney JF, Weg JG, Chenevert TL, Stafford-Johnson D, Hamilton BH, Prince MR. Diagnosis of pulmonary embolism with magnetic resonance angiography. N Engl J Med 1997;336(20):1422–1427.[Abstract/Free Full Text]
33. Oudkerk M, van Beek EJ, Wielopolski P, et al. Comparison of contrast-enhanced magnetic resonance angiography and conventional pulmonary angiography for the diagnosis of pulmonary embolism: a prospective study. Lancet 2002;359(9318):1643–1647.[CrossRef][Medline]
34. Gupta A, Frazer CK, Ferguson JM, et al. Acute pulmonary embolism: diagnosis with MR angiography. Radiology 1999;210(2):353–359.[Abstract/Free Full Text]
35. Harris KG, Smith TP, Cragg AH, Lemke JH. Nephrotoxicity from contrast material in renal insufficiency: ionic versus nonionic agents. Radiology 1991;179(3):849–852.[Abstract/Free Full Text]
36. Barrett BJ, Carlisle EJ. Metaanalysis of the relative nephrotoxicity of high- and low-osmolality iodinated contrast media. Radiology 1993;188(1):171–178.[Abstract/Free Full Text]
37. Schwab SJ, Hlatky MA, Pieper KS, et al. Contrast nephrotoxicity: a randomized controlled trial of a nonionic and an ionic radiographic contrast agent. N Engl J Med 1989;320(3):149–153.[Abstract]
38. Merten GJ, Burgess WP, Gray LV, et al. Prevention of contrast-induced nephropathy with sodium bicarbonate: a randomized controlled trial. JAMA 2004;291(19):2328–2334.[Abstract/Free Full Text]
39. Chertow GM. Prevention of radiocontrast nephropathy: back to basics. JAMA 2004;291(19):2376–2377.[Free Full Text]
40. Waybill MM, Waybill PN. Contrast media-induced nephrotoxicity: identification of patients at risk and algorithms for prevention. J Vasc Interv Radiol 2001;12(1):3–9.[Medline]
41. Heupler FA Jr. Guidelines for performing angiography in patients taking metformin. Members of the Laboratory Performance Standards Committee of the Society for Cardiac Angiography and Interventions. Cathet Cardiovasc Diagn 1998;43(2):121–123.[CrossRef][Medline]
42. Cook JV, Kyriou J. Radiation from CT and perfusion scanning in pregnancy. BMJ 2005;331(7512):350.[Free Full Text]
43. Parker MS, Hui FK, Camacho MA. Female breast radiation exposure during CT pulmonary angiography. AJR Am J Roentgenol 2005;185(5):1228–1233.[Abstract/Free Full Text]
44. Task Group on Control of Radiation Dose in Computed Tomography. Managing patient dose in computed tomography. A report of the International Commission on Radiological Protection. Ann ICRP 2000;30(4):7–45.[Medline]
45. Eichinger S. D-dimer testing in pregnancy. Pathophysiol Haemost Thromb 2003;33(5-6):327–329.[CrossRef][Medline]
46. Matthews S. Imaging pulmonary embolism in pregnancy: what is the most appropriate imaging protocol? Br J Radiol 2006;79(941):441–444.[Abstract/Free Full Text]
47. Schuster ME, Fishman JE, Copeland JF, Hatabu H, Boiselle PM. Pulmonary embolism in pregnant patients: a survey of practices and policies for CT pulmonary angiography. AJR Am J Roentgenol 2003;181(6):1495–1498.[Abstract/Free Full Text]
48. Magnevist [package insert]. Wayne, NJ: Berlex Laboratories, revised May, 2000.
49. Hurwitz LM, Yoshizumi T, Reiman RE, et al. Radiation dose to the fetus from body MDCT during early gestation. AJR Am J Roentgenol 2006;186(3):871–876.[Abstract/Free Full Text]
50. Cheriex EC, Sreeram N, Eussen YF, Pieters FA, Wellens HJ. Cross sectional Doppler echocardiography as the initial technique for the diagnosis of acute pulmonary embolism. Br Heart J 1994;72(1):52–57.[Abstract/Free Full Text]
51. Mansencal N, Redheuil A, Joseph T, et al. Use of transthoracic echocardiography combined with venous ultrasonography in patients with pulmonary embolism. Int J Cardiol 2004;96(1):59–63.[CrossRef][Medline]
52. Rudoni RR, Jackson RE, Godfrey GW, Bonfiglio AX, Hussey ME, Hauser AM. Use of two-dimensional echocardiography for the diagnosis of pulmonary embolus. J Emerg Med 1998;16(1):5–8.[CrossRef][Medline]
53. Grifoni S, Olivotto I, Cecchini P, et al. Utility of an integrated clinical, echocardiographic, and venous ultrasonographic approach for triage of patients with suspected pulmonary embolism. Am J Cardiol 1998;82(10):1230–1235.[CrossRef][Medline]

This article has been cited by other articles:

				V. King, A. A. Vaze, C. S. Moskowitz, L. J. Smith, and M. S. Ginsberg D-Dimer Assay to Exclude Pulmonary Embolism in High-Risk Oncologic Population: Correlation with CT Pulmonary Angiography in an Urgent Care Setting Radiology, June 1, 2008; 247(3): 854 - 861. [Abstract] [Full Text] [PDF]

				J. Glassroth Evaluation of Suspected Pulmonary Embolism During Pregnancy--Reply JAMA, April 9, 2008; 299(14): 1665 - 1666. [Full Text] [PDF]

				S. Moll A Clinical Perspective of Venous Thromboembolism Arterioscler. Thromb. Vasc. Biol., March 1, 2008; 28(3): 373 - 379. [Full Text] [PDF]

				S. P. Kalva, J. P. Jagannathan, P. F. Hahn, and S. T. Wicky Venous Thromboembolism: Indirect CT Venography during CT Pulmonary Angiography--Should the Pelvis Be Imaged? Radiology, February 1, 2008; 246(2): 605 - 611. [Abstract] [Full Text] [PDF]

				L. M. Freeman Don't Bury the V/Q Scan: It's as Good as Multidetector CT Angiograms with a Lot Less Radiation Exposure J. Nucl. Med., January 1, 2008; 49(1): 5 - 8. [Full Text] [PDF]

				A. Falanga, A. Y. Y. Lee, M. B. Streiff, and G. H. Lyman Anticoagulation in the Treatment of Venous Thromboembolism in Patients with Cancer ASCO Educational Book, January 1, 2008; 2008(1): 258 - 268. [Abstract] [Full Text] [PDF]

				G. Bierry, F. Kellner, C. Barnig, P. K. Woodard, L. R. Goodman, J. G. Weg, and P. D. Stein Management of Patients with History of Adverse Effects to Contrast Media When Pulmonary Artery CT Angiography Is Required Radiology, December 1, 2007; 245(3): 919 - 921. [Full Text] [PDF]

				M. Remy-Jardin, M. Pistolesi, L. R. Goodman, W. B. Gefter, A. Gottschalk, J. R. Mayo, and H. D. Sostman Management of Suspected Acute Pulmonary Embolism in the Era of CT Angiography: A Statement from the Fleischner Society Radiology, November 1, 2007; 245(2): 315 - 329. [Full Text] [PDF]

				A. M. Strashun A Reduced Role of V/Q Scintigraphy in the Diagnosis of Acute Pulmonary Embolism J. Nucl. Med., September 1, 2007; 48(9): 1405 - 1407. [Full Text] [PDF]

				L. R. Goodman, P. D. Stein, A. Beemath, H. D. Sostman, T. W. Wakefield, P. K. Woodard, and D. F. Yankelevitz CT Venography for Deep Venous Thrombosis: Continuous Images Versus Reformatted Discontinuous Images Using PIOPED II Data Am. J. Roentgenol., August 1, 2007; 189(2): 409 - 412. [Abstract] [Full Text] [PDF]

				H. Arakawa, T. Kohno, T. Hiki, and Y. Kaji CT Pulmonary Angiography and CT Venography: Factors Associated with Vessel Enhancement Am. J. Roentgenol., July 1, 2007; 189(1): 156 - 161. [Abstract] [Full Text] [PDF]

				C. H. McCollough, B. A. Schueler, T. D. Atwell, N. N. Braun, D. M. Regner, D. L. Brown, and A. J. LeRoy Radiation Exposure and Pregnancy: When Should We Be Concerned? RadioGraphics, July 1, 2007; 27(4): 909 - 917. [Abstract] [Full Text] [PDF]

				N. Tunariu, S. J.R. Gibbs, Z. Win, W. Gin-Sing, A. Graham, P. Gishen, and A. AL-Nahhas Ventilation-Perfusion Scintigraphy Is More Sensitive than Multidetector CTPA in Detecting Chronic Thromboembolic Pulmonary Disease as a Treatable Cause of Pulmonary Hypertension J. Nucl. Med., May 1, 2007; 48(5): 680 - 684. [Abstract] [Full Text] [PDF]

This Article Figures Only Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal