1. Correct Answer: D. A near-field clutter artifact

Rationale: Near-field clutter is an artifact caused by the transducer’s high-amplitude oscillations affecting or obscuring structures present in the near field. This is especially relevant when apical ventricular thrombus is suspected since the image can resemble that of a thrombus. However, unlike a thrombus, clutter is unaffected by ventricular wall motion and, at times, can appear to pass through the ventricular wall. Changing from fundamental to harmonic imaging is helpful in reducing this type of artifact, as well as side-lobe and reverberation artifacts. If there is still uncertainty, switching to other imaging planes, using contrast agents, decreasing depth, and improving near-field resolution can also reduce or eliminate this type of artifact. Cardiac myxomas are usually globular in structure, appear heterogeneous, and more commonly occur in the left atrium where the site of attachment is almost always in the region of the fossa ovalis.

Risk factors for the development of left ventricular thrombus are associated with regions of wall motion abnormality and include large infarct size, severe apical asynergy (i.e., akinesia or dyskinesia), left ventricular aneurysm, and anterior myocardial infarction. Left ventricular thrombi usually have defined margins, are seen throughout systole and diastole, are located adjacent to an area of hypokinesia or akinesia, and are seen from at least two views. Table 38.1 summarizes some of the structures or artifacts that can mimic a thrombus in the left ventricle.

1. Bertrand PB, Levine RA, Isselbacher EM, Vandervoort PM. Fact or artifact in two-dimensional echocardiography: avoiding misdiagnosis and missed diagnosis. J Am Soc Echocardiogr. 2016;29(5):381-391.

2. Brenes JC, Asher CR. Cardiac ultrasound artifacts. In: Klein AL, ed. Clinical Echocardiography Review. 2nd ed. Wolters Kluwer; 2018:15-29.

3. Delewi R, Zijlstra F, Piek JJ. Left ventricular thrombus formation after acute myocardial infarction. Heart. 2012;98:1743-1749.

4. Galiuto L, Badano L, Fox K, Sicari R, Zamorano JL. The EAE Textbook of Echocardiography. Oxford University Press; 2011:9.

5. Peters PJ, Reinhardt S. The echocardiographic evaluation of intracardiac masses: a review. J Am Soc Echocardiogr. 2006;19:230-240.

2. Correct Answer: B. A range-ambiguity artifact (RAA)

Rationale: RAA is an erroneous mapping of returning echoes into a composite picture. RAA occurs when an object outside the field of view reflects ultrasound waves that are not received until early in the next cycle. This in turn results in an appearance of deep structures closer to the transducer than they actually are. RAA can be eliminated by decreasing depth or adjusting the transducer position.

The moderator band is a conspicuous muscular ridge present in the RV and is usually noted as the most prominent trabecula, extending from the septum to the free wall. Thrombus in transit appears as a serpentine density, normally extending from the right atrium into the RV. A side-lobe artifact results when side energy lateral to the central beam of the transducer encounters a strong reflector, producing an image that appears as originating from the central beam though it is actually lateral to the true object location. An acoustic shadowing artifact occurs when there is increased attenuation by structures leading to an image that is darkened distal to the increased attenuation.

1. Brenes JC, Asher CR. Cardiac ultrasound artifacts. In: Klein AL, ed. Clinical Echocardiography Review. 2nd ed. Wolters Kluwer; 2018:15-29.

2. Kremkau FW, Taylor KJ. Artifacts in ultrasound imaging. J Ultrasound Med. 1986 Apr;5(4):227-237.

3. Puello F, Harewood J, Lee C, Rupani N, Abe O. Thrombus in transit: the emergence of a deadly diagnosis. Chest. 2017 Oct;152(4):A1021.

4. Rajiah P, MacNamara J, Chaturvedi A, Ashwath R, Fulton NL, Goerne H. Bands in the heart: multimodality imaging review. Radiographics. 2019 Sep-Oct;39(5):1238-1263.

3. Correct Answer: C. Thrombus

Rationale: The combination of blood stasis, endothelial injury, and hypercoagulability, often referred to as Virchow’s triad, is a prerequisite for thrombus formation. In myocardial infarction, regional wall akinesia or dyskinesia results in blood stasis. Prolonged ischemia leads to subendocardial tissue injury, and acute coronary syndrome can promote a hypercoagulable state. This triad can result in the formation of left ventricular thrombus.

Risk factors for the development of left ventricular thrombus include large infarct size, severe apical akinesis or dyskinesis, left ventricular aneurysm, and anterior wall myocardial infarction.

TTE is the technique used most often to help identify patients at high risk for thromboembolism and to assess the presence, shape, and size of the thrombus. It can also be used to monitor resolution of thrombus with anticoagulation. Left ventricular thrombus is defined as a discrete echodense mass in the left ventricle with defined margins that are distinct from the endocardium and seen throughout systole and diastole. It should be located adjacent to an area of hypokinesis or akinesis and seen in at least two planes. Structures such as false tendons and trabeculae can mimic a left ventricular thrombus, as can side-lobe, near-field, and reverberation artifacts. Cardiac myxomas, on the other hand, are heterogeneous globular structures attached to the endocardial surface by a stalk commonly arising from the surface of the fossa ovalis of the left atrium.

1. Delewi R, Zijlstra F, Piek JJ. Left ventricular thrombus formation after acute myocardial infarction. Heart. 2012;98:1743-1749.

2. Echocardiography and coronary artery disease. In: Armstrong WF, Ryan T, eds. Feigenbaum’s Echocardiography. 8th ed. Wolters Kluwer; 2019:427-459

3. Quien MM, Saric M. Ultrasound imaging artifacts: how to recognize them and how to avoid them. Echocardiography. 2018;35(9):1388-1401.

4. Correct Answer: D. Metastatic disease

Rationale: Figure 38.4 shows a right ventricular mass, likely a tumor. Cardiac tumors are rare in general, but metastasis to the heart from other primary cancers is 30 times more common. Table 38.2 lists the primary cancers that metastasize to the heart.

There are a few primary cardiac tumors, and myxomas are the most common. These are benign tumors that usually occur in the left atrium, with the attachment site commonly at the fossa ovalis of the atrial septum. Only 25% of primary cardiac tumors are malignant, and of these, 75% are sarcomas. Malignant primary cardiac sarcomas are usually located in the right atrium and are most commonly angiosarcomas. In the left atrium, the most common malignant tumors are pleomorphic sarcomas and leiomyosarcomas.

Symptom presentation for cardiac tumors is dependent upon tumor location and size, rather than upon histologic characteristics. These include congestive heart failure from intracardiac obstruction, systemic embolization, constitutional symptoms, and arrhythmias. The pattern of heart and pericardium tumor involvement provides information important to the differential diagnosis of the cardiac condition. This determination can be made in part by diagnostic imaging, including but not limited to echocardiography.

Histopathologic determination is crucial for definitive diagnosis of a mass lesion as a type of primary tumor, a secondary metastatic neoplasm, or a nonneoplastic process. There are a number of pseudotumors that can resemble cardiac tumors. These include intracavitary thrombi or foreign bodies, intramural abscesses or hematomas, ventricular aneurysms, and coronary artery aneurysms. Cystic lesions of the pericardium are typically benign. Malignant lesions are more likely to produce pericardial adhesions, hemorrhagic pericardial effusion, or both. A solitary intramyocardial mass in the ventricular wall is likely to be a primary benign tumor, whereas multiple myocardial nodules are more likely to represent metastatic malignancy.

1. Armstrong WF, Ryan T. Feigenbaum’s Echocardiography. 8th ed. Wolters Kluwer; 2019.

2. Buja LM. The multifaceted manifestations of cardiac tumors. Tex Heart Inst J. 2012;39(1):84-85.

3. Leja MJ, Shah DJ, Reardon MJ. Primary cardiac tumors. Tex Heart Inst J. 2011;38(3):261-262.