Can Contrast-Enhanced Multi-Detector Computed Tomography Replace Transesophageal Echocardiography for the Detection of Thrombogenic Milieu and Thrombi in the Left Atrial Appendage: A Prospective Study with 124 Patients

Abstract

Purpose: To assess the diagnostic value of contrast-enhanced multi-detector computed tomography (MD-CT) for identifying patients with left atrial appendage (LAA) thrombus or circulatory stasis.

Materials and Methods: 124 patients with a history of atrial fibrillation and/or cerebral ischemia (83 men, mean age 58.6 ± 12.4 years) and with a clinical indication for MD-CT of the heart and for transesophageal echocardiography (TEE) were included in the study. LAA thrombus or thrombogenic milieu was visually identified in TEE and MD-CT. In addition, MD-CT was analyzed quantitatively measuring the Hounsfield units (HU) of the left atrium (LA), the LAA and the ascending aorta (AA), and calculating the HU ratios LAA/AA (HU [LAA/AA]) und LAA/LA (HU [LAA/LA]). Sensitivity, specificity, negative predictive value (NPV) and positive predictive value (PPV) were calculated.

Results: The prevalence of a thrombus or thrombogenic milieu as assessed by TEE was 21.8 %. The HU ratio was lower in patients with thrombus or thrombogenic milieu (HU [LAA/AA]: 0.590 ± 0.248 vs. 0.909 ± 0.141; p < 0.001 und HU [LAA/LA] 0.689 ± 0.366 vs. 1.082 ± 0.228; p < 0.001). For the diagnosis of thrombus or a thrombogenic milieu, visual analysis yielded a sensitivity of 81.5 %, a specificity of 96.9 %, a PPV of 87.5 % and a NPV of 95.2 %. By combining visual and quantitative analysis with one criterion being positive, the specificity decreased to 91.8 %, the sensitivity to 77.8 %, the PPV to 72.4 %, and the NPV to 94.9 %.

Conclusion: Visual analysis of the LAA in the evaluation of thrombus or thrombogenic milieu yields a high NPV of 95.1 % and may especially be useful to rule out LAA thrombi in patients with contraindications for TEE. Additional calculation of HU ratios did not improve the diagnostic performance of MD-CT.

Key Points:

• MD-CT can reliably exclude atrial appendage thrombi/thrombogenic milieu.

• MD-CT is an alternative method in patients with contraindications to TEE.

• Calculation of relative HU ratios does not improve the diagnostic value of MD-CT.

Citation Format:

• Homsi R, Nath B, Luetkens JA et al. Can Contrast-Enhanced Multi-Detector Computed Tomography Replace Transesophageal Echocardiography for the Detection of Thrombogenic Milieu and Thrombi in the Left Atrial Appendage: A Prospective Study with 124 Patients. Fortschr Röntgenstr 2016; 188: 45 – 52

Zusammenfassung

Ziel: Die Bestimmung der diagnostischen Aussagekraft der kontrastmittelverstärkten Computertomografie (MD-CT) hinsichtlich der Beurteilung des linken Vorhofs (LA) und des linken Vorhofohrs (LAA) zur Detektion von Thromben oder eines hohen thrombogenen Milieus.

Material und Methoden: Es wurden 124 Patienten mit Vorhofflimmern und/oder zerebraler Ischämie (83 Männer, Durchschnittsalter 58,6 ± 12,4 Jahre) eingeschlossen bei denen die Indikation zur Durchführung einer transösophagealen Echokardiografie (TEE) und zusätzlich einer MD-CT des Herzens bestand. Ein LAA-Thrombus oder hohes thrombogenes Milieu wurden visuell mittels TEE und MD-CT beurteilt. Zusätzlich wurden die MD-CTs quantitativ über die Bestimmung der mittleren Röntgendichte in LA, LAA und Aorta ascendens (AA) und der berechneten relativen Röntgendichte LAA/AA (rD [LAA/AA]) und LAA/LA (rD [LAA/LA]) analysiert. Sensitivität, Spezifität, negativ prädiktiver Wert (NPV) und positiv prädiktiver Wert (PPV) wurden berechnet.

Ergebnisse: Die Prävalenz eines Thrombus oder eines hohen thrombogenen Milieus im TEE betrug 21,8 %. Die rD waren bei Patienten mit Thrombus oder hohem thrombogenen Milieu erniedrigt (rD [LAA/AA]: 0,590 ± 0,248 vs. 0,909 ± 0,141; p < 0,001 und rD [LAA/LA] 0,689 ± 0,366 vs. 1,082 ± 0,228; p < 0,001). Die visuelle Bildanalyse der MD-CT für die Diagnose eines Thrombus oder eines hohen thrombogenen Milieus ergab verglichen mit der TEE eine Sensitivität von 81,5 %, eine Spezifität von 96,9 %, einen PPV von 87,5 % und einen NPV von 95,2 %. Durch die Kombination von visueller und quantitativer Analyse, wobei eines der beiden Kriterien positiv sein musste, verschlechterte sich die Sensitivität auf 77,8 %, die Spezifität auf 91,8 %, der PPV auf 72,4 % und der NPV auf 94,9 %.

Schlussfolgerung: Die visuelle Beurteilung der MD-CT weist mit 95,1 % einen hohen NPV auf und stellt bei Patienten mit einer Kontraindikation für die Durchführung einer TEE eine diagnostische Alternative dar. Die zusätzliche Berechnung relativer Dichtewerte verbessert die diagnostische Aussagekraft der MD-CT nicht.

Kernaussagen:

• Die MD-CT kann LAA-Thromben und thrombogenes Milieu mit hoher Sicherheit ausschließen.

• Bei TEE-Kontraindikationen kann die MD-CT als alternative Untersuchungsmethode eingesetzt werden.

• Die Bestimmung relativer Dichtewerte verbessert die Detektion von Thromben/thrombogenem Milieu nicht.

Key words

echocardiography - cardiac - CT - left atrial appendage - thrombus

• References

• 1 Bonita R. Epidemiology of stroke. Lancet 1992; 339: 342-344
• 2 Camm AJ, Kirchhof P, Lip GY et al. Guidelines for the management of atrial fibrillation: the Task Force for the Management of Atrial Fibrillation of the European Society of Cardiology (ESC). Europace 2010; 12: 1360-1420
• 3 Harrison MJ, Marshall J. Atrial fibrillation, TIAs and completed strokes. Stroke 1984; 15: 441-442
• 4 Hilberath JN, Oakes DA, Shernan SK et al. Safety of transesophageal echocardiography. J Am Soc Echocardiogr 2010; 23: 1115-1127 ; quiz 1220–1111
• 5 Hur J, Kim YJ, Lee HJ et al. Left atrial appendage thrombi in stroke patients: detection with two-phase cardiac CT angiography versus transesophageal echocardiography. Radiology 2009; 251: 683-690
• 6 Kim YY, Klein AL, Halliburton SS et al. Left atrial appendage filling defects identified by multidetector computed tomography in patients undergoing radiofrequency pulmonary vein antral isolation: a comparison with transesophageal echocardiography. American heart journal 2007; 154: 1199-1205
• 7 Martinez MW, Kirsch J, Williamson EE et al. Utility of nongated multidetector computed tomography for detection of left atrial thrombus in patients undergoing catheter ablation of atrial fibrillation. JACC Cardiovascular imaging 2009; 2: 69-76
• 8 Wu X, Wang C, Zhang C et al. Computed tomography for detecting left atrial thrombus: a meta-analysis. Archives of medical science: AMS 2012; 8: 943-951
• 9 Fatkin D, Kelly RP, Feneley MP. Relations between left atrial appendage blood flow velocity, spontaneous echocardiographic contrast and thromboembolic risk in vivo. Journal of the American College of Cardiology 1994; 23: 961-969
• 10 Hur J, Kim YJ, Lee HJ et al. Cardioembolic stroke: dual-energy cardiac CT for differentiation of left atrial appendage thrombus and circulatory stasis. Radiology 2012; 263: 688-695
• 11 Hausleiter J, Meyer T, Hermann F et al. Estimated radiation dose associated with cardiac CT angiography. JAMA 2009; 301: 500-507
• 12 Manning WJ, Weintraub RM, Waksmonski CA et al. Accuracy of transesophageal echocardiography for identifying left atrial thrombi. A prospective, intraoperative study. Ann Intern Med 1995; 123: 817-822
• 13 Hwang JJ, Chen JJ, Lin SC et al. Diagnostic accuracy of transesophageal echocardiography for detecting left atrial thrombi in patients with rheumatic heart disease having undergone mitral valve operations. The American journal of cardiology 1993; 72: 677-681
• 14 Manning WJ, Silverman DI, Katz SE et al. Impaired left atrial mechanical function after cardioversion: relation to the duration of atrial fibrillation. Journal of the American College of Cardiology 1994; 23: 1535-1540
• 15 Achenbach S, Barkhausen J, Beer M et al. Consensus recommendations of the German Radiology Society (DRG), the German Cardiac Society (DGK) and the German Society for Pediatric Cardiology (DGPK) on the use of cardiac imaging with computed tomography and magnetic resonance imaging. Fortschr Röntgenstr 2012; 184: 345-368
• 16 Dorenkamp M, Sohns C, Vollmann D et al. Detection of left atrial thrombus during routine diagnostic work-up prior to pulmonary vein isolation for atrial fibrillation: role of transesophageal echocardiography and multidetector computed tomography. International journal of cardiology 2013; 163: 26-33
• 17 Tang RB, Dong JZ, Zhang ZQ et al. Comparison of contrast enhanced 64-slice computed tomography and transesophageal echocardiography in detection of left atrial thrombus in patients with atrial fibrillation. Journal of interventional cardiac electrophysiology: an international journal of arrhythmias and pacing 2008; 22: 199-203
• 18 Rastegar R, Harnick DJ, Weidemann P et al. Spontaneous echo contrast videodensity is flow-related and is dependent on the relative concentrations of fibrinogen and red blood cells. Journal of the American College of Cardiology 2003; 41: 603-610
• 19 Shapiro MD, Neilan TG, Jassal DS et al. Multidetector computed tomography for the detection of left atrial appendage thrombus: a comparative study with transesophageal echocardiography. Journal of computer assisted tomography 2007; 31: 905-909
• 20 Staab W, Sohns C, Zwaka PA et al. Split-bolus single-phase cardiac multidetector computed tomography for reliable detection of left atrial thrombus: comparison to transesophageal echocardiography. Fortschr Röntgenstr 2014; 186: 1009-1015
• 21 Singh NK, Nallamothu N, Zuck VP et al. Left atrial appendage filling defects on 64-slice multidetector computed tomography in patients undergoing pulmonary vein isolation: predictors and comparison to transesophageal echocardiography. Journal of computer assisted tomography 2009; 33: 946-951
• 22 Monzen H, Shimoyama H, Hirata M et al. The optimal cardiac phase for detecting the thrombi of the left atrial appendage on multi-slice computed tomography in patients with atrial fibrillation. Radiol Phys Technol 2010; 3: 78-83
• 23 Nishino M, Kubo T, Kataoka ML et al. Coronal reformations of the chest on 64-row multi-detector row CT: evaluation of image quality in comparison with 16-, 8- and 4-row multi-detector row CT. Eur J Radiol 2006; 59: 231-237
• 24 Rodman T, Pastor BH, Figueroa W. Effect on cardiac output of conversion from atrial fibrillation to normal sinus mechanism. Am J Med 1966; 41: 249-258
• 25 Handke M, Harloff A, Hetzel A et al. Left atrial appendage flow velocity as a quantitative surrogate parameter for thromboembolic risk: determinants and relationship to spontaneous echocontrast and thrombus formation – a transesophageal echocardiographic study in 500 patients with cerebral ischemia. J Am Soc Echocardiogr 2005; 18: 1366-1372
• 26 Kerl JM, Ravenel JG, Nguyen SA et al. Right heart: split-bolus injection of diluted contrast medium for visualization at coronary CT angiography. Radiology 2008; 247: 356-364
• 27 Delewi R, Zijlstra F, Piek JJ. Left ventricular thrombus formation after acute myocardial infarction. Heart 2012; 98: 1743-1749
• 28 Srichai MB, Junor C, Rodriguez LL et al. Clinical, imaging, and pathological characteristics of left ventricular thrombus: a comparison of contrast-enhanced magnetic resonance imaging, transthoracic echocardiography, and transesophageal echocardiography with surgical or pathological validation. American heart journal 2006; 152: 75-84
• 29 Mohrs OK, Nowak B, Petersen SE et al. Thrombus detection in the left atrial appendage using contrast-enhanced MRI: a pilot study. Am J Roentgenol 2006; 186: 198-205
• 30 Romero J, Cao JJ, Garcia MJ et al. Cardiac imaging for assessment of left atrial appendage stasis and thrombosis. Nat Rev Cardiol 2014; 11: 470-480