Rationale and Objectives
The aim of this study was to evaluate a new formula for the rapid assessment of pericardial effusion (PE) volume by computed tomography.
Materials and Methods
Twenty computed tomographic scans positive for PE were reviewed by two observers. Diameters of PE were measured at four locations. Additionally, PE volume was assessed by volumetry. The correlation between PE diameters and volume was evaluated, and a linear equation was derived for each diameter location. To test validity and reliability of the measurements, intraclass correlation and Bland-Altman analysis were performed.
Results
Good validity was expressed by strong correlations between diameter measurements at all four locations and PE volume (all R values >0.80 and P values <.0001). Intraclass correlation (all coefficients >0.75) and Bland-Altman analysis revealed good interobserver and intraobserver reliability of diameter measurements. The best values were observed for apical diameter measurements. The following linear equation was derived for apical diameter measurements: PE volume = 296 (mL/cm) × apical diameter (cm) − 32 mL.
Conclusions
PE volume can rapidly be assessed by apical PE diameter measurement using the simplified formula PE volume = 0.3 (L/cm) × apical diameter (cm).
The heart is surrounded by the pericardium, which consists of two layers. The outer layer is called the parietal pericardium and the inner layer the visceral pericardium . The space between the two layers, the pericardial cavity, normally contains a small amount of pericardial fluid, typically between 15 and 50 mL , which reduces friction within the pericardium by allowing the pericardial layers to glide over each other with every heartbeat. Abnormal accumulation of fluid in the pericardial cavity is called pericardial effusion (PE). The etiology of PE can be idiopathic, iatrogenic, metabolic, or caused by neoplasia, infection, or connective tissue disease . If a critical rate of pericardial fluid accumulation relative to pericardial stretch is reached, increasing intrapericardial pressure can lead to a severe decrease in cardiac function . This life-threatening condition is called cardiac tamponade. The critical pericardial fluid volume that leads to cardiac tamponade depends on whether the volume increases slowly or rapidly over time. Nevertheless, volumes of nonhemorrhagic effusions ranging from 300 to 600 mL have been reported to cause cardiac tamponade .
In certain patient cohorts, PE can be frequently detected as an incidental finding on computed tomographic (CT) examinations. For example, the incidence rate of PE in patients undergoing CT imaging of the pulmonary arteries for suspected pulmonary embolism ranges between 2% and 5% .
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Materials and methods
Study Population
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Imaging Technique
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Image Analysis
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Statistical Analysis
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Results
Data Distributions
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Reliability of Volume Measurements
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Reliability of Diameter Measurements
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Table 1
Reliability of Pericardial Diameter Measurements at Distinct Locations
Anterior Posterior Apical Superior Aortic Recess Intraobserver reliability Intraclass correlation coefficient 0.80 0.87 0.97 0.92 Bland-Altman (cm) 0.04 ± 0.82 −0.08 ± 0.79 0.01 ± 0.42 0.06 ± 0.72 Interobserver reliability Intraclass correlation coefficient 0.81 0.82 0.95 0.89 Bland-Altman (cm) 0.03 ± 0.88 0.12 ± 0.99 0.07 ± 0.55 0.06 ± 0.85
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Validity of Diameter Measurements
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Table 2
Correlation (Validity) between Diameter Measurements and Pericardial Effusion Volume Assessed by Volumetry and Derived Linear Equation
Anterior Posterior Apical Superior Aortic Recess Correlation coefficient 0.83 0.88 0.89 0.83P <.0001 <.0001 <.0001 <.0001 Coefficient of determination 0.69 0.78 0.80 0.70 Linear equation_y_ = 332 x − 132y = 308 x − 35y = 296 x − 32y = 263 x − 287
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Derivation of Equation for PE Volume Estimation
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Discussion
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Conclusions
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PEvolume=0.3(L/cm)×apicaldiameter(cm). PE
volume
=
0.3
(
L
/
cm
)
×
apical
diameter
(
cm
)
.
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References
1. Truong M.T., Erasmus J.J., Gladish G.W., et. al.: Anatomy of pericardial recesses on multidetector CT: implications for oncologic imaging. AJR Am J Roentgenol 2003; 181: pp. 1109-1113.
2. Scherer A., Choy G., Kropil P., et. al.: Cardiac pathologies incidentally detected with non-gated chest CT. [article in German] Rofo 2009; 181: pp. 1127-1134.
3. Restrepo C.S., Lemos D.F., Lemos J.A., et. al.: Imaging findings in cardiac tamponade with emphasis on CT. Radiographics 2007; 27: pp. 1595-1610.
4. Yared K., Baggish A.L., Picard M.H., et. al.: Multimodality imaging of pericardial diseases. JACC Cardiovasc Imaging 2010; 3: pp. 650-660.
5. Tian L, Liu LZ, Cui CY, et al. CT findings of primary non-teratomatous germ cell tumors of the mediastinum—a report of 15 cases. Eur J Radiol. In press.
6. Imazio M., Spodick D.H., Brucato A., et. al.: Controversial issues in the management of pericardial diseases. Circulation 2010; 121: pp. 916-928.
7. Eichler K., Zangos S., Thalhammer A., et. al.: CT-guided pericardiocenteses: clinical profile, practice patterns and clinical outcome. Eur J Radiol 2010; 75: pp. 28-31.
8. Da Ines D., Chabrot P., Motreff P., et. al.: Cardiac tamponade after malignant superior vena cava stenting: two case reports and brief review of the literature. Acta Radiol 2010; 51: pp. 256-259.
9. Spodick D.H.: Acute cardiac tamponade. N Engl J Med 2003; 349: pp. 684-690.
10. Hall W.B., Truitt S.G., Scheunemann L.P., et. al.: The prevalence of clinically relevant incidental findings on chest computed tomographic angiograms ordered to diagnose pulmonary embolism. Arch Intern Med 2009; 169: pp. 1961-1965.
11. Lee E.Y., Kritsaneepaiboon S., Zurakowski D., et. al.: Beyond the pulmonary arteries: alternative diagnoses in children with MDCT pulmonary angiography negative for pulmonary embolism. AJR Am J Roentgenol 2009; 193: pp. 888-894.
12. Groth M, Henes FO, Mayer U, et al. Age-related incidence of pulmonary embolism and additional pathologic findings detected by computed tomography pulmonary angiography. Eur J Radiol. In press.
13. Tomoda H., Hoshiai M., Furuya H., et. al.: Evaluation of pericardial effusion with computed tomography. Am Heart J 1980; 99: pp. 701-706.
14. Busing K.A., Kilian A.K., Schaible T., et. al.: Reliability and validity of MR image lung volume measurement in fetuses with congenital diaphragmatic hernia and in vitro lung models. Radiology 2008; 246: pp. 553-561.
15. Bland J.M., Altman D.G.: Statistical methods for assessing agreement between two methods of clinical measurement. Lancet 1986; 1: pp. 307-310.
16. Costa-Santos C., Bernardes J., Ayres-de-Campos D., et. al.: The limits of agreement and the intraclass correlation coefficient may be inconsistent in the interpretation of agreement. J Clin Epidemiol 2011; 64: pp. 264-269.
17. Groth M., Henes F.O., Bannas P., et. al.: Intraindividual comparison of contrast-enhanced MRI and unenhanced SSFP sequences of stenotic and non-stenotic pulmonary artery diameters. Rofo 2011; 183: pp. 47-53.
18. Tsang T.S., Barnes M.E., Hayes S.N., et. al.: Clinical and echocardiographic characteristics of significant pericardial effusions following cardiothoracic surgery and outcomes of echo-guided pericardiocentesis for management: Mayo Clinic experience 1979-1998. Chest 1999; 116: pp. 322-331.
19. D’Cruz I.A., Hoffman P.K.: A new cross sectional echocardiographic method for estimating the volume of large pericardial effusions. Br Heart J 1991; 66: pp. 448-451.
20. Leibowitz D., Perlman G., Planer D., et. al.: Quantification of pericardial effusions by echocardiography and computed tomography. Am J Cardiol 2011; 107: pp. 331-335.
21. Prakash R., Moorthy K., Del Vicario M., et. al.: Reliability of echocardiography in quantitating pericardial effusion: a prospective study. J Clin Ultrasound 1977; 5: pp. 398-402.