Pulmonary embolism CT
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Pulmonary Embolism Microchapters |
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Pulmonary Embolism Assessment of Probability of Subsequent VTE and Risk Scores |
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Pulmonary embolism CT On the Web |
Editor(s)-In-Chief: The APEX Trial Investigators, C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-In-Chief: Cafer Zorkun, M.D., Ph.D. [2]
Overview
The traditional gold standard for diagnosing PE is contrast pulmonary angiography. However, invasiveness, its high costs, limited availability and need of an expert radiologist are some of its negative aspects. This chapter deals with the advantages of multidetector CT over CTPA.
Single-Detector CT
Recent improvement in technology has changed the value of CT angiography for decision making in suspected PE patients. Wide variations regarding both sensitivity (53-100%) and specificity (73-100%) was reported in studies about single detector spiral CT in suspected PE cases.[1][2]
Two large multicentric robust clinical studies including more than 1000 patients reported a sensitivity around 70% and a specificity of 90% for single-detector CT.[3][4] Due to motion artifacts and insufficient opacification, the rate of technical inadequacy of CT was 5-8%.
Two large studies have shown that a combination of a negative SDCT and an absence of proximal lower limb DVT on lower limb venous ultrasonoagraphy in Non-high clinical probability patient was associated with a 3-month thromboembolic risk of 1%.[5][6]
Multi-Detector CT
Since its introduction. CT angiography has become the method of choice for imaging the pulmonary vasculature for suspected PE patients in routine clinical practice.
Advantage of MDCT over SDCT
- High spatial resolution.
- High temporal resolution.
- Better quality of arterial opacification.
- Adequate visualization of pulmonary arteries upto at least the segmental level.
Supportive Trial Date
A study enrolling 94 patients, done in 2004, showed the sensitivity and specificity to be above 90%.[7]
The PIOPED II study, which enrolled 824 patients, published its result in 2006, showing a sensitivity and specificity to be 83% and 96% respectively.[8] Though PIOPED II has been criticized for the choice of its reference diagnostic criteria, it has highlighted the influence of clinical probability on the predictive value of MDCT.
A Canadian trial compared V/Q scan and CT (mostly MDCT). The 3 month thromboembolic risk would have been 1.5% (95% CI, 0.1-1.2%) if only CT has been used.[9]
Another study with enrollment of 1819 patients, compared two diagnostic strategies based on D-dimer and MDCT, one with and the other without lower limb compression ultrasonography (CUS). The study reported that the 3-month thromboembolic risk was 0.3% (95% CI 0.1-1.1) in the D-dimer-Ultrasonography-CT (DD-US-CT) group and 0.3% (0.1-1.2) in the DD-CT group (difference 0.0% [-0.9 to 0.8]). In the DD-US-CT group, ultrasonography showed a deep-venous thrombosis in 53 (9% [7-12]) of 574 patients, and thus MDCT was not undertaken.[10]
Role of MDCT in diagnosing PE[11]
- In patients with non-high clinical probability of PE, negative MDCT is an adequate criteria for excluding PE.
- In patients with high clinical probability of PE, there is still a controversy that whether patient with a negative CT should be further investigated by compression ultrasonography and/or vetilation-perfusion (V/Q) scintigraphy or pulmonary angiography.[11]
- In patients with non-low clinical probability of PE:
- A MDCT showing PE at segmental or more proximal level is an adequate proof of PE in those patients.
- According to PIOPED II, the PPV of MDCT was found to be low (58%)[8] so further testing should be considered in case of negative MDCT.
Role of MDCT in assessment of right ventricular dysfunction
Right ventricular dysfunction is an independent predictor of clinical deterioration and death, thus it can be used for risk stratification for adverse outcomes. Thus MDCT has the potential to provide both diagnostic and prognostic stratification in acute pulmonary embolism patients.
- In a study, a right-to-left ventricular dimensional ratio <0.9 at MDCT was found to have a 100% NPV for death due to PE.[12]
- This could also be used to identify those patients at low risk of death, who are candidates for early discharge or home treatment.
ESC Guideline Recommendations [11]
Suspected High-risk PE Patients
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Class I1. In high-risk pulmonary embolism, as indicated by the presence of shock or hypotension, emergency CT or bedside echocardiography (depending on availability and clinical circumstances) is recommended for diagnostic purposes. (Level of Evidence: C) |
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Suspected Non High-risk PE Patients
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Low clinical probabilityClass I1. Normal D-dimer level using either a highly or moderately sensitive assay excludes pulmonary embolism. (Level of Evidence: A) Intermediate clinical probabilityClass I1. Negative multi-detector CT (MDCT) safely excludes pulmonary embolism. (Level of Evidence: A) 2. Negative single-detector CT (SDCT) only excludes pulmonary embolism when combined with negative proximal compression ultrasonography. (Level of Evidence: A) 3. SDCT or MDCT showing a segmental or more proximal thrombus confirms pulmonary embolism. (Level of Evidence: A) Class IIa1. Further testing should be considered to confirm pulmonary embolsim if SDCT or MDCT shows only subsegmental clots. (Level of Evidence: B) High clinical probabilityClass I1. SDCT or MDCT showing a segmental or more proximal thrombus confirms pulmonary embolism. (Level of Evidence: A) Class IIa B1. In patients with a negative CT, further tests should be considered in selected patients to exclude pulmonary embolism. (Level of Evidence: B) |
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Guideline Resources
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[11]
References
- ↑ Mullins MD, Becker DM, Hagspiel KD, Philbrick JT (2000). "The role of spiral volumetric computed tomography in the diagnosis of pulmonary embolism". Arch. Intern. Med. 160 (3): 293–8. PMID 10668830. Retrieved 2012-04-30. Unknown parameter
|month=ignored (help) - ↑ Rathbun SW, Raskob GE, Whitsett TL (2000). "Sensitivity and specificity of helical computed tomography in the diagnosis of pulmonary embolism: a systematic review". Ann. Intern. Med. 132 (3): 227–32. PMID 10651604. Retrieved 2012-04-30. Unknown parameter
|month=ignored (help) - ↑ Perrier A, Howarth N, Didier D, Loubeyre P, Unger PF, de Moerloose P, Slosman D, Junod A, Bounameaux H (2001). "Performance of helical computed tomography in unselected outpatients with suspected pulmonary embolism". Ann. Intern. Med. 135 (2): 88–97. PMID 11453707. Retrieved 2012-04-30. Unknown parameter
|month=ignored (help) - ↑ Van Strijen MJ, De Monye W, Kieft GJ, Pattynama PM, Prins MH, Huisman MV (2005). "Accuracy of single-detector spiral CT in the diagnosis of pulmonary embolism: a prospective multicenter cohort study of consecutive patients with abnormal perfusion scintigraphy". J. Thromb. Haemost. 3 (1): 17–25. doi:10.1111/j.1538-7836.2004.01064.x. PMID 15634261. Retrieved 2012-04-30. Unknown parameter
|month=ignored (help) - ↑ Musset D, Parent F, Meyer G, Maître S, Girard P, Leroyer C, Revel MP, Carette MF, Laurent M, Charbonnier B, Laurent F, Mal H, Nonent M, Lancar R, Grenier P, Simonneau G (2002). "Diagnostic strategy for patients with suspected pulmonary embolism: a prospective multicentre outcome study". Lancet. 360 (9349): 1914–20. doi:10.1016/S0140-6736(02)11914-3. PMID 12493257. Retrieved 2012-04-30. Unknown parameter
|month=ignored (help) - ↑ Perrier A, Roy PM, Aujesky D, Chagnon I, Howarth N, Gourdier AL, Leftheriotis G, Barghouth G, Cornuz J, Hayoz D, Bounameaux H (2004). "Diagnosing pulmonary embolism in outpatients with clinical assessment, D-dimer measurement, venous ultrasound, and helical computed tomography: a multicenter management study". Am. J. Med. 116 (5): 291–9. doi:10.1016/j.amjmed.2003.09.041. PMID 14984813. Retrieved 2012-04-30. Unknown parameter
|month=ignored (help) - ↑ Winer-Muram HT, Rydberg J, Johnson MS, Tarver RD, Williams MD, Shah H, Namyslowski J, Conces D, Jennings SG, Ying J, Trerotola SO, Kopecky KK (2004). "Suspected acute pulmonary embolism: evaluation with multi-detector row CT versus digital subtraction pulmonary arteriography". Radiology. 233 (3): 806–15. doi:10.1148/radiol.2333031744. PMID 15564410. Retrieved 2012-05-01. Unknown parameter
|month=ignored (help) - ↑ 8.0 8.1 Stein PD, Fowler SE, Goodman LR, Gottschalk A, Hales CA, Hull RD, Leeper KV, Popovich J, Quinn DA, Sos TA, Sostman HD, Tapson VF, Wakefield TW, Weg JG, Woodard PK (2006). "Multidetector computed tomography for acute pulmonary embolism". N. Engl. J. Med. 354 (22): 2317–27. doi:10.1056/NEJMoa052367. PMID 16738268. Retrieved 2012-05-01. Unknown parameter
|month=ignored (help) - ↑ Anderson DR, Kahn SR, Rodger MA, Kovacs MJ, Morris T, Hirsch A, Lang E, Stiell I, Kovacs G, Dreyer J, Dennie C, Cartier Y, Barnes D, Burton E, Pleasance S, Skedgel C, O'Rouke K, Wells PS (2007). "Computed tomographic pulmonary angiography vs ventilation-perfusion lung scanning in patients with suspected pulmonary embolism: a randomized controlled trial". JAMA. 298 (23): 2743–53. doi:10.1001/jama.298.23.2743. PMID 18165667. Retrieved 2012-05-01. Unknown parameter
|month=ignored (help) - ↑ Righini M, Le Gal G, Aujesky D, Roy PM, Sanchez O, Verschuren F, Rutschmann O, Nonent M, Cornuz J, Thys F, Le Manach CP, Revel MP, Poletti PA, Meyer G, Mottier D, Perneger T, Bounameaux H, Perrier A (2008). "Diagnosis of pulmonary embolism by multidetector CT alone or combined with venous ultrasonography of the leg: a randomised non-inferiority trial". Lancet. 371 (9621): 1343–52. doi:10.1016/S0140-6736(08)60594-2. PMID 18424324. Retrieved 2012-05-01. Unknown parameter
|month=ignored (help) - ↑ 11.0 11.1 11.2 11.3 Torbicki A, Perrier A, Konstantinides S, Agnelli G, Galiè N, Pruszczyk P, Bengel F, Brady AJ, Ferreira D, Janssens U, Klepetko W, Mayer E, Remy-Jardin M, Bassand JP (2008). "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. 29 (18): 2276–315. doi:10.1093/eurheartj/ehn310. PMID 18757870. Retrieved 2012-05-01. Unknown parameter
|month=ignored (help) - ↑ Becattini C, Agnelli G, Vedovati MC, Pruszczyk P, Casazza F, Grifoni S, Salvi A, Bianchi M, Douma R, Konstantinides S, Lankeit M, Duranti M (2011). "Multidetector computed tomography for acute pulmonary embolism: diagnosis and risk stratification in a single test". Eur. Heart J. 32 (13): 1657–63. doi:10.1093/eurheartj/ehr108. PMID 21504936. Retrieved 2012-05-01. Unknown parameter
|month=ignored (help)