Diagnostic Imaging Pathways - Pulmonary Embolism (Haemodynamically Stable)
- Pathway Home
- Pathway
- Images
- Teaching Points
- ct
- cxr
- ddimer
- factors
- ivc
- lowdosectpa
- us
- vq
- wells
- References
- Information for Consumers
- copyright
Pathway Home
Population Covered By The Guidance
This pathway provides guidance on imaging patients with suspected pulmonary embolism.
Date reviewed: March 2012
Date of next review: January 2015
Published: March 2012
Quick User Guide
Move the mouse cursor over the PINK text boxes inside the flow chart to bring up a pop up box with salient points.
Clicking on the PINK text box will bring up the full text.
The relative radiation level of each imaging investigation is displayed in the pop up box.
| SYMBOL | RRL | EFFECTIVE DOSE RANGE | |
 |
None | 0 | |
 |
Minimal | < 1 millisieverts | |
 |
Low | 1-5 mSv | |
 |
Medium | 5-10 mSv | |
 |
High | >10 mSv |
Images
Image GalleryNote: These images open in a new page | ||
|---|---|---|
| 1 |  |
Hampton's Hump Image 1 (Plain Radiograph): There is a peripheral wedge shaped opacity representing pulmonary infarction and atelectasis secondary to a pulmonary embolus (arrow). This radiographic sign is referred to as Hampton's Hump. |
| 2a |  |
Bilateral Pulmonary Embolism Image 2a and 2b (Computed Tomography): Axial and reconstructed images of bilateral pulmonary arterial emboli (arrows) |
| 2b |  |
|
| 3 |  |
Bilateral Pulmonary Embolism Image 3 (Ventilation Perfusion Scan): The ventilation series demonstrates uniform distribution of tracer throughout both lung fields. The perfusion series demonstrates generalised reduced tracer uptake in the right lung with multiple segmental and subsegmental perfusion defects throughout both lung fields. These findings have a high probability for recent pulmonary embolism. |
Teaching Points
Teaching Points
- Pulmonary embolism (PE) refers to obstruction of the pulmonary artery or one of its branches by material (e.g. thrombus, tumor, air, or fat) that originated elsewhere in the body 61
- The role of a chest radiograph in suspected PE is to exclude other causes that may mimic PE and to guide further investigations
- Prior to imaging, the probability of PE must be calculated clinically. This is based on the validated 'Wells Criteria'
- Clinical signs and symptoms of deep vein thrombosis (DVT)
- PE as or more likely than an alternative diagnosis
- Previous history of DVT
- Active cancer
- Recent immobilisation
- Tachycardia
- Haemoptysis
- Patients who are at low probability for PE should have a D-Dimer. A negative D-Dimer in a low probability case of suspected PE rules out the diagnosis and no further investigatioin is indicated
- Patients with moderate to high pre-test probability of PE should have further imaging
- The choice of imaging is reliant on a 'normal' chest radiograph and whether the patient has a history of a chronic underlying lung disease
- Patients with a normal chest radiograph and no history of lung disease should proceed to radionuclide scan
- Patients with an abnormal chest radiograph or history of lung disease should proceed to CTPA
ct
Computed Tomography Pulmonary Angiography (CTPA)
- Demonstrates a pulmonary embolism by showing a filling defect within contrast filled pulmonary arteries
- New generation MDCT (64 slice helical scanners) with low tube currents (80kVp, 100kVp and 120kVp) with/without dose modulations have been shown to not effect image quality of the angiography studies and at the same time have reduced effective radiation doses by 40% to 60% compared to the older scanners(140kVp). 55,56,57 Also of note is the increase in contrast enhancement with low voltage scans and reduced amount of contrast medium needed for the study 58
- The radiation exposure is of particular importance to young females with breast tissue that has a higher turnover rate, who are therefore most susceptible to radiation-induced carcinogenesis. The absorbed dose to the breast tissue by CTPA was estimated between 10-30mGy, which was 30-40 times greater compared to a perfusion scan but recent studies with newer MDCT scanners have been shown to deliver much lower organ doses to breast skin and breast parenchyma 55
- Studies using bismuth breast shields have shown radiation dose reductions of 34-57% to the breast, without significant decrease in image quality or diagnostic accuracy 35,36,37
- The role of CTPA in the diagnostic algorithm for PE is dependent to some
degree on the type of scanner available
- Older scanners are limited by relatively long scan times and the associated respiratory motion artifact 1
- Multi-slice CTPA has a number of advantages over older scanners that make it the central imaging modality for the investigation of PE at many centres
- The Prospective Investigation of Pulmonary Embolism Diagnosis II (PIOPED II) trial reported a sensitivity of 83% and specificity of 96% using mainly 4-row multi-detector CT(MDCT) without consistent use of bolus tracking contrast administration. Discordant CTPA and pre-test clinical risk stratification required further investigation. The negative predictive value of high risk patients with a negative CTPA was only 60% and the positive predictive value of patients at low risk with a positive CTPA was 58%. A relatively high rate (6%) of studies were non-diagnostic 39
- A recent randomised study by Righini et al, compared one group who were assessed with D-Dimer followed by multislice CTPA, to another group had D-Dimer followed by lower limb venous ultrasonography and CTPA for exclusion of pulmonary embolism. Their primary outcome was the proportion of venous thromboembolic events in the 3-month follow-up period in each group in patients who were left untreated on the basis of the exclusion of pulmonary embolism by the diagnostic strategy. They found no difference in the the 3 month thromboembolic risk between the groups (0.3% for each group respectively). Based on this evidence, pulmonary embolism can effectively be excluded with a negative CTPA in patients who have a low or moderate pretest probability 40
- CT is also able to provide information on alternative diagnoses that may mimic PE 16,17 Also has high sensitivity, specificity and accuracy in chronic PE. Also, CTPA findings may correlate with surgical outcomes in these cases 59, 60
- Limitations
- Radiation exposure if standard protocol if being implemented
- Risk of contrast allergy and renal impairment
- Subject to interpretive pitfalls such as respiratory motion artifact, streak artifact and problems related to patient body habitus 25
cxr
Chest Radiograph
- Mainly useful for excluding conditions that can mimic pulmonary embolism 18
- Features 19
- Approximately 12% of patients with angiographically proven PE have a normal chest radiograph
- The most common chest radiograph findings with PE are atelectasis and parenchymal opacities in the affected lung zone
- Oligaemia was the only chest radiograph finding that occurred significantly more frequently in patients with PE compared to those without
- Positive predictive value of a normal chest radiograph - 18%
- Negative predictive value of a normal chest radiograph - 74%
- The other main use of a chest radiograph is to assist in determining whether a VQ or a CTPA is the most appropriate next investigation
ddimer
D-Dimer Assay
- D-dimer is formed as a result of plasmin generated degradation of thrombin and is therefore a marker of the presence of thrombus
- There are various qualitative and quantitative assays available for D-dimer, but in general they have a high sensitivity and negative predictive value for the presence of thrombus 26,27
- Of the various assays, the quantitative enzyme linked immunosorbent assay (ELISA) has the best negative likelihood ratio and is significantly superior to non-ELISA assays for excluding the presence of pulmonary embolism (sensitivity >90%, specificity 40%) 28,29,41
- A negative quantitative ELISA D-dimer result is as diagnostically useful for excluding PE as a normal helical CT lung scan. 28 In such patients, the 3-month risk of thromboembolism is only 0.14% (95% confidence interval, 0.05 to 0.41) if no anti-coagulation is given 47
- A negative D-dimer result in a highly sensitive assay (e.g. ELISA) safely excludes PE in patients with a low or moderate clinical probability 28,29 while a moderately sensitive assay excludes PE only in patients with a low clinical probability 41
- When using the dichotomous clinical prediction rule(which classifies patients as PE unlikely and PE likely), a negative D-dimer result is able to exclude PE safely in PE-unlikely patients either by a highly sensitive or moderately sensitive assay 41
- When PE is suspected, a normal D-Dimer avoids further investigation in about 50% of outpatients and 20% of inpatients 48
factors
Factors Influencing Choice Of Further Test
- A radionuclide scan emits a lower radiation dose compared to a standard dose (120KvP) CT pulmonary angiogram (CTPA) and is therefore preferred in younger patients
- Radionuclide scans should also be performed in those with contraindications to CT with contrast including patients with iodinated contrast allergy and with severe renal impairment. For more details, see section on Contrast Media and Contrast Induced Nephrotoxicity
- Radionuclide scans are frequently non-diagnostic in those with abnormalities on chest radiography or with known chronic lung disease and CTPA should be considered in these patients
- Availablity of new generation MDCTs with dose reduction technologies can also influence the choice of investigation as these have been shown to cause far less radiation exposure compared to traditional CTPAs 58
- Patient's body habitus, inability to co-operate with CT examination may hinder performing CTPA in these patients and radionuclide V-Q scan may need to be used
ivc
Inferior Vena Cava Filters
- Routine use of IVC filters is not recommended
- Should be considered in patients with 26
- Recurrent pulmonary emboli arising from lower limb or pelvis despite therapeutic anticoagulation
- Contraindication to anticoagulation
lowdosectpa
Low Dose Computed Tomography Pulmonary Angiography (CTPA)
- New generation MDCT (64 slice helical scanners) with low tube currents (80kVp, 100kVp and 120kVp) with / without dose modulations have been shown to not effect image quality of the angiography studies and at the same time have reduced effective radiation doses by 40% to 60% compared to the older scanners(140kVp). 55 Also of note is the increase in contrast enhancement with low voltage scans and reduced amount of contrast medium needed for the study 58
- Where these MDCTs are available, they can be the first choice of modality in acute PE even in young women so long as no contraindications for contrast material exist
us
Bilateral Leg Doppler Ultrasound
- The role of Doppler ultrasound in the evaluation of patients with suspected PE is controversial
- Approximately 10% of patients with a PE will have an abnormal ultrasound and a further 2% will have evidence of DVT on serial scans 22
- May be useful if the pretest probability is discordant with the result of the VQ scan or CTPA 22
- Advantages
- Widely available
- Non-invasive
- Limitations
- Low sensitivity for patients with PE
vq
Radionuclide Lung Scan
- Lung perfusion images are taken after the intravenous injection of technetium-99m macroaggregated albumin. A PE characteristically appears as a pleural based segmental perfusion defect 1
- Any perfusion defects are compared to ventilation images and any regions of mismatch are considered suspect for PE 1
- Ventilation perfusion scans, compared to CTPA, are associated with lower radiation exposure but the extreme difference between the effective doses as existed previously has been reduced drastically with the new generation MDCT helical scanners that use low dose (using tube currents of 100kVp or 120kVp) 55,56,57,58
- A perfusion scan alone (without the ventilation scan) can lead to significant reductions in cost and radiation exposure. A normal perfusion scan excludes PE with a negative predictive value close to 100% 42,49,50,51
- A Ventilation-Perfusion scan has the following diagnostic features 21
- A high-probability scan usually indicates PE but only a minority of patients with PE have a high probability scan
- A low-probability scan combined with a low pre-test probability of PE makes a PE very unlikely
- An intermediate-probability scan is not usually helpful in establishing a diagnosis. Patients with a intermediate-probability scan (or low-probability scan with a high pretest probability) should be reviewed and considered for further testing with a CTPA if there is persisting clinical suspicion for PE
- Limitations
- Frequent non-diagnostic results, particularly for patients with an abnormal chest radiograph or a significant history of chronic obstructive lung disease 20
- Advantages
- Lower radiation exposure compared to standard dose CT Pulmonary Angiography
- Widely available
- A normal scan useful for excluding PE in the majority of patients 21
- High sensitivity, specificity and accuracy in chronic pulmonary embolism and is the first choice of investigation in chronic thromboembolic pulmonary hypertension 59,60
wells
Clinical Prediction Rules For Pretest Probability Of Pulmonary Embolism
- Clinical prediction rules are now well accepted as key components in the diagnostic approach to pulmonary embolism. The posttest probability of PE depends not only on the accuracy of the test but also on the pretest probability as determined by these prediction rules 41,42
- The Wells Criteria is extensively validated and effectively triages patients into three pretest probability groups based on the following clinical variables 23,24
- Clinical signs and symptoms of deep venous thrombosis (leg swelling and deep venous pain): 3 points
- Other alternative diagnosis less likely than PE: 3 points
- Previously objectively diagnosed DVT or PE: 1.5 points
- Active cancer (less than 6 months since therapy or palliative stage): 1 point
- Recent Immobilisation: 1.5 points
- Bedrest for at least 3 consecutive days
- Surgery in the previous 4 weeks
- Heart rate greater than 100 per minute: 1.5 points
- Haemoptysis: 1 point
- Total Score: 0-1 = Low, 2-6 = Intermediate, 7+ = High probability
- Revised Geneva Score is another widely accepted set of clinical prediction rules for Pulmonary embolism and one distinct advantage of the Revised Geneva Score is the complete objectiveness of the scoring system compared to Wells criteria's subjective clinician's assessment of "An alternative diagnosis is less likely than PE" criterion which carries significant weight (3 points) 52,53
- Age over 65 years: 1 point
- Previous DVT or PE: 3 points
- Surgery (under general anaesthesia) or fracture of the lower limbs within 1 month: 2 points
- Active malignant condition (solid or haematological, currently active or considered cured <1 year): 2 points
- Unilateral lower-limb pain: 3 points
- Haemoptysis: 2 points
- Heart rate 75-94/min: 3 points
- Heart rate >94/min: 5 points
- Pain on lower-limb deep venous palpation and unilateral oedema: 4 points
- Total probability score: Low <3, Intermediate 4-10, High >10
- Whichever rule is used, the proportion of patients with PE is around 10% in the low probability category, 30% in the moderate probability category and 65% in the high clinical probability category 41,42
References
References
References are graded from Level I to V according to the Oxford Centre for Evidence-Based Medicine, Levels of Evidence. Download the document
- Donkers-van Rossum AB. Diagnostic strategies for suspected pulmonary embolism. Eur Respir J. 2001;18:589-97. (Review article)
- Van Beek EJR, Reekers JA, Batchelor D, et al. Feasibility, safety and clinical utility of angiography in patients with suspected pulmonary embolism and non-diagnostic lung scan findings. Eur Radiol. 1996;6:415-9. (Level III evidence)
- Johnson MS, Stine SB, Shah H, et al. Possible pulmonary embolus: evaluation with digital subtraction versus cut-film angiography - prospective study in 80 patients. Radiology. 1998;207:131-8. (Level III evidence)
- Hagspiel KD, Polak JF, Grassi CJ, et al. Pulmonary embolism: comparison of cut-film and digital pulmonary angiography. Radiology. 1998;207:139-45. (Level III evidence)
- Hudson ER, Smith TP, McDermott VG, et al. Pulmonary angiography with iopamidol: complications in 1434 patients. Radiology. 1996;198:61-5. (Level III evidence)
- Van Rooij WJ, den Heeten GJ, Sluzewski M. Pulmonary embolism: diagnosis in 211 patients with the use of selective pulmonary digital subtraction angiography with a flow-directed catheter. Radiology. 1995;195:793-7. (Level III evidence)
- Stein PD, Athanasoulis C, Alavi A, et al. Complications and validity of pulmonary angiography in acute pulmonary embolus. Circulation. 1992;85:462-8. (Level II evidence). View the reference
- Diffin D, Leyendecker JR, Johnson SP, Zucker RJ, Grebe PJ. Effect of anatomic distribution of pulmonary emboli on interobserver agreement in the interpretation of pulmonary angiography. AJR Am J Roentgenol. 1998;171:1085-9. (Level II evidence). View the reference
- Stein PD, Henry JW, Gottschalk A. Reassessment of pulmonary angiography for the diagnosis of pulmonary embolism: relation of interpreter agreement to the order of the involved pulmonary arterial branch. Radiology. 1999;210:689-91. (Level II evidence). View the reference
- McCollough CH, Zink FE. Performance evaluation of a multi-slice CT system. Med Phys. 1999;26:2223-30. (Level II evidence)
- Schoepf UJ, Holzknecht N, Helmberger TK, et al. Subsegmental pulmonary emboli: improved detection with thin-collimation multi-detector row spiral CT. Radiology. 2002;222:483-90. (Level IV evidence)
- Schoepf UJ, Costello P. CT angiography for diagnosis of pulmonary embolism: state of the art. Radiology. 2004;230:329-37. (Review article)
- Patel S, Kazerooni EA, Cascade PN. Pulmonary embolism: optimization of small pulmonary artery visualization at multi-detector row CT. Radiology. 2003;227:455-60. (Level II evidence). View the reference
- Remy-Jardin M, Tillie-Leblond I, Szapiro D, et al. CT angiography of pulmonary embolism in patients with underlying respiratory disease: impact of multislice CT on image quality and negative predictive value. Eur Radiol. 2002;12:1971-8. (Level IV evidence)
- Coche E, Verschuren F, Keyeux A, et al. Diagnosis of acute pulmonary embolism in outpatients: comparison of thin-collimation multi-collimation multi-detector spiral CT and planar ventilation-perfusion scintigraphy. Radiology. 2003;229:757-65. (Level III evidence)
- Kim KI, Muller NL, Mayo JR. Clinically suspected pulmonary embolism: utility of spiral CT. Radiology. 1999;210:693-7. (Level III evidence)
- Garg K, Sieler H, Welsh CH, et al. Clinical validity of helical CT being interpreted as negative for pulmonary embolism: implications for patient treatment. AJR Am J Roentgenol. 1999;172:1627-31. (Level IV evidence)
- Worsley DF, Alavi A. Radionuclide imaging of acute pulmonary embolism. Radiol Clin North Am. 2001;39:1035-52. (Review article)
- Worsley DF, Alavi A, Palevsky HI. Chest radiographic findings in patients with acute pulmonary embolism: observations from the PIOPED study. Radiology. 1993;189:133-6. (Level II evidence). View the reference
- Forbes KPN, Reid JH, Murchison JT. Do preliminary chest x-ray findings define the optimum role of pulmonary scintigraphy in suspected pulmonary embolism. Clin Radiol. 2001;56:397-400. (Level III evidence)
- The PIOPED Investigators. Value of the ventilation/perfusion scan in acute pulmonary embolism: results of the prospective investigation of pulmonary embolism diagnosis (PIOPED). JAMA. 1990;263:2753-9. (Level II evidence). View the reference
- 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;129:997-1005. (Level II evidence). View the reference
- 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;83:416-20. (Level II evidence). View the reference
- 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;135:98-107. (Level II evidence). View the reference
- Aviram G, Levy G, Fishman JE. Pitfalls in the diagnosis of acute pulmonary embolism on spiral computer tomography. Curr Probl Diagn Radiol. 2004;33:74-84. (Level IV evidence)
- Ho WK, Hankey GJ, Lee CH, Eikelboom JW. Venous thromboembolism: diagnosis and management of pulmonary embolism. Med J Aust. 2005;182:569-74. (Review article)
- Freyburger G, Trillaud H, Labrouche S, et al. D-dimer strategy in thrombosis exclusion - a gold standard study in 100 patients suspected of deep venous thrombosis or pulmonary embolism: 8 DD methods compared. Thromb Haemost. 1998;79:32-7. (Level II evidence). View the reference/a>
- Stein PD, Hull RD, Patel KC, et al. D-Dimer for the exclusion of acute venous thrombosis and pulmonary embolism: a systematic review. Ann Intern Med. 2004;140:589-602. (Level I evidence). View the reference
- Roy P-M, Colombet I, Durieux P, Chatellier G, Sors H, Meyer G. Systematic review and meta-analysis of strategies for the diagnosis of suspected pulmonary embolism. BMJ. 2005;331:259-67. (Level I evidence) View the reference
- Patel S, Kazerooni EA. Helical CT for the evaluation of acute pulmonary embolism. AJR Am J Roentgenol. 2005;185:135-49. (Review article)
- European Commission. Referral guidelines for imaging. Luxembourg. Office for Official Publications of the European Communities. 2001
- United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). UNSCEAR 2000 Report to the General Assembly. Annex D: Medical Radiation Exposures. 2000 [cited 2005 August 24]. View the report
- Parker MS, Hui FK, Camacho MA, Chung JK, Broga DW, Sethi NN. Female breast radiation exposure during CT pulmonary angiography. AJR Am J Roentgenol. 2005;185:1228-33. (Level II evidence). View the reference
- Cook JV, Kyriou J. Radiation from CT and perfusion scanning in pregnancy. BMJ. 2005;331:350 (Letter)
- Hopper KD, King SH, Lobell ME, TenHave TR, Weaver JS. The breast: in-plane x-ray protection during diagnostic thoracic CT – shielding with bismuth radioprotective garments. Radiology. 1997; 205:853-8. (Level II evidence)
- Hopper KD. Orbital, thyroid, and breast superficial radiation shielding for patients undergoing diagnostic CT. Semin Ultrasound CT MR. 2002;23:423-7. (Level IV evidence)
- Colombo P, Pedroli G, Nicoloso M, Re S, Valvassori L, Vanzulli A. Evaluation of the efficacy of a bismuth shield during CT examinations. Radiol Med (Torino). 2004;108:560-8. (Level II evidence)
- Committee to Assess Health Risks from Exposure to Low Levels of Ionizing Radiation, National Research Council. Health risks from exposure to low levels of ionizing radiation: BEIR VII Phase 2. 2006 [cited 2006 May 26] (Level II evidence). View the reference
- Stein PD, Fowler SE, Goodman LR et al. Multidetector computed tomography for acute pulmonary embolism. N Engl J Med. 2006;354:2317-27. (Level II evidence). View the reference
- Righini M, Le Gal G, Aujesky D, Roy PM, Sanchez O, Verschuren F, et al. Diagnosis of pulmonary embolism by multidetector CT alone or combined with venous ultrasonography of the leg: a randomised non-inferiority trial. Lancet. 2008;371(9621):1343-52. (LevelI evidence). View the reference
- Torbicki A, Perrier A, Konstantinides S, Agnelli G, Galie N, Pruszczyk P, Bengel F, et al. Guidelines on the diagnosis and management of acute pulmonary embolism: the Task Force for the Diagnosis and Management of Acute Pulmonary Embolism of the European Society of Cardiology (ESC). Eur Heart J. 2008;29(18):2276-315. (Clinical guidelines). View the reference
- Stein PD, Woodard PK, Weg JG, Wakefield TW, Tapson VF, Sostman HD, et al. Diagnostic pathways in acute pulmonary embolism: recommendations of the PIOPED II Investigators. Radiology. 2007;242(1):15-21. (Clinical guidelines). View the reference
- van Belle A, Buller HR, Huisman MV, Huisman PM, Kaasjager K, Kamphuisen PW et al. Effectiveness of managing suspected pulmonary embolism using an algorithm combining clinical probability, D-dimer testing, and computed tomography. JAMA. 2006;295:172-9. (Level II evidence)
- Sohne M, Kamphuisen PW, van Mierlo PJ, Buller HR. Diagnostic strategy using a modified clinical decision rule and D-dimer test to rule out pulmonary embolism in elderly in- and outpatients. Thromb Haemost. 2005;94:206-10. (Level III evidence)
- Kearon C, Ginsberg JS, Douketis J, Turpie AG, Bates SM, Lee AY et al. An evaluation of D-dimer in the diagnosis of pulmonary embolism: a randomized trial. Ann Intern Med. 2006;144:812-21. (Level II evidence)
- Le Gal G, Righini M, Roy PM, Sanchez O, Aujesky D, Bounameaux H et al. Prediction of pulmonary embolism in the emergency department: the revised Geneva score. Ann Intern Med. 2006;144:165-71. (Level II evidence)
- Carrier M, Righini M, Djurabi RK, et al. VIDAS D-dimer in combination with clinical pre-test probability to rule out pulmonary embolism: a systematic review of management outcome studies. Thromb Haemost. 2009;101:886-92. (Level I evidence). View the reference
- Agnelli G and Becattini C. Acute pulmonary embolism. N Engl J Med. 2010;363:266-74. (Review article)
- Remy-Jardin M, Pistolesi M, Goodman LR, Gefter WB, Gottschalk A, Mayo JR, et al. Management of suspected acute pulmonary embolism in the era of CT angiography: a statement from the Fleischner Society. Radiology. 2007;245(2):315-29. (Review article)
- Hull RD, Raskob GE, Coates G, Panju AA. Clinical validity of a normal perfusion lung scan in patients with suspected pulmonary embolism. Chest. 1990;97:23-6. (Level II evidence)
- Kipper MS, Moser KM, Kortman KE,Ashburn WL. Long term follow-up in patients with suspected pulmonary embolism and a normal lung scan.Chest. 1982;82:411-15. (Level III evidence)
- Wong DD, Ramaseshan G, Mendelson RM.Comparison of the Wells and Revised Geneva Scores for the diagnosis of pulmonary embolism: an Australian experience. Int Med J. 2011;41(3):258-63. (Level II evidence)
- Klok FA, Kruisman E, Spaan J, Nijkeuter M, Righini M, Aujesky D, Roy PM, Perrier A, Le Gal G, Huisman MV. Comparison of the revised Geneva score with the Wells rule for assessing clinical probability of pulmonary embolism. J Thromb Haemost. 2008;6(1):40-4. (Level III evidence)
- Douma RA, Mos IC, Erkens PM, Nizet TA, Durian MF, Hovens MM, van Houten AA, Hofstee HM, Klok FA, ten Cate H, Ullmann EF, Büller HR, Kamphuisen PW, Huisman MVPerformance of 4 clinical decision rules in the diagnostic management of acute pulmonary embolism: a prospective cohort study. Ann Int Med. 2011;154(11):709-18. (Level II evidence)
- Litmanomic D, Tack D, Lin PJ, Boiselle PM, Raptopoulos V, Bankier AA. Female breast, lung, and pelvic organ radiation from dose-reduced 64-MDCT thoracic examination protocols: a phantom study. AJR Am J Roentgenol. 2011;197:929-34. (Level III evidence)
- Zsolt SF, Fabian S, Jennifer C, Jaled CT, Michael AP, Stephan R, Hanno H, Rolf W, Peter V, Sebastian TS. Diagnostic accuracy of pulmonary CT angiography at low tube voltage: intraindividual comparison of a normal-dose protocol at 120 kVp and a low-dose protocol at 80 kVp using reduced amount of contrast medium in a simulation study. AJR Am J Roentgenol. 2011;197:W852-9 (web exclusive article)
- Zsolt SF, Luzia K, Tamara S, Michael AP, Peter V, Sebastian TS. Patient exposure and image quality of low-dose pulmonary computed tomography angiography comparison of 100- and 80-kVp protocols. Invest Radiol. 2008;43:871-6. (Level III evidence)
- Zamboni GA, et al. Low voltage CTPA for patients with suspected pulmonary embolism. Eur J Radiol. 2012;81(4):e580-4. (Level III evidence)
- He J, Fang W, Lv B, He JG, Xiong CM, Liu ZH, He ZX. Diagnosis of chronic thromboembolic pulmonary hypertension: comparison of ventilation/perfusion scanning and multidetector computed tomography pulmonary angiography with pulmonary angiography. Nucl Med Commun. 2012;33(5):459-63. (Level II evidence)
- Mehta S, Helmersen D, Provencher S, et al. Diagnostic evaluation and management of chronic thromboembolic pulmonary hypertension: A clinical practice guideline. Can Respir J. 2010;17(6):301-34. (Guidelines)
- Thomson BT, Hales CA. Overview of acute pulmonary embolism In: UpToDate, Basow, DS (Ed), UpToDate, Waltham, MA, 2012. Topic Updated: 2012 Feb 03 ; Topic Accessed: 2012 Mar 01
Information for Consumers
Information for Consumers
Information from this website |
Information from the Royal Australian and New Zealand College of Radiologists’ website |
|
Consent to Procedure or Treatment Radiation Risks of X-rays and Scans Computed Tomography (CT) Angiography Inferior Vena Cava (IVC) Filters |
Iodine-Containing Contrast Medium Radiation Risk of Medical Imaging During Pregnancy Radiation Risk of Medical Imaging for Adults and Children |
copyright
Copyright
© Copyright 2015, Department of Health Western Australia. All Rights Reserved. This web site and its content has been prepared by The Department of Health, Western Australia. The information contained on this web site is protected by copyright.
Legal Notice
Please remember that this leaflet is intended as general information only. It is not definitive and The Department of Health, Western Australia can not accept any legal liability arising from its use. The information is kept as up to date and accurate as possible, but please be warned that it is always subject to change
.File Formats
Some documents for download on this website are in a Portable Document Format (PDF). To read these files you might need to download Adobe Acrobat Reader.
