Imaging pitfalls, artifacts, and normal variants mimicking cardiac masses





Key points





  • Anatomic variants occurring in normal cardiac developments often simulate pathologic entities.



  • Anatomic variants are particularly common in the right atrium.



  • Due to the physical properties of ultrasound waves and specifics in ultrasound image reconstruction, cardiologists often encounter ultrasound image artifacts. It is particularly important to recognize such artifacts to avoid misdiagnosis of conditions ranging from aortic dissection to thrombosis and endocarditis.



Table 3.1

Structures potentially mimicking cardiac masses in echocardiography.













Structures potentially mimicking cardiac masses in echocardiography
Left ventricle webs, heartstrings, chords
Apical trabeculations
Dilated coronary sinus (PLAX view)
Dilated descending aorta (A4C view)
Multiple lobes of the left atrial appendage
Pectinate muscles of the right/left atrial appendage
Prominent moderator band
Prominent crista terminalis
Nodules of Arantius
Dystrophic calcification of the mitral valve
Noncompaction cardiomyopathy
Prominent papillary muscle
Lipomatous hypertrophy of the interatrial septum
Pacemaker wires
Central venous catheters
Valvular interventional devices
Near beam artifact
Reverberation
Enhancement
Refraction
Mirror image
Prominent Eustachian valve
Prominent Chiari network
Redundant mitral chordae or redundant leaflet tissue
Prominent epicardial fat pad
Apical hypertrophic cardiomyopathy
Interatrial septal aneurysm
Lambl’s excrescence
Occluder interatrial/interventricular devices

Fig. 3.2


The images depict the accessory mitral valve tissue. Transthoracic echocardiography of two patients (A and B) shows a round, cystic-like echo density attached to the anterior mitral valve leaflet and seen in the left ventricular outflow tract, compatible with accessory mitral valve tissue (Supplementary Video 3.1).




Accessory mitral valve tissue (AMWT) is a rare congenital cardiac anomaly sometimes responsible for left ventricular outflow tract (LVOT) obstruction. AMVT is most often associated with other cardiac and vascular congenital malformations such as septal defects and transposition of the great arteries ( Supplementary Video 3.1 ).


Patients with AMVT may be asymptomatic with the presence of a murmur; nonetheless, more frequently, they experience symptoms like dyspnea. Usually, patients become symptomatic when the mean gradient across the LVOT reaches 50 mmHg.


Signs of LVOT obstruction generally develop during the first decade of life in one-third of the patients and include typical symptoms. The current approach is intervention only for patients with significant LVOT obstruction (mean gradient ≥ 25 mmHg) and those undergoing correction of other congenital malformations or exploration of an intracardiac mass. For patients without significant LVOT obstruction, a follow-up with serial echocardiography to assess the progression of the gradient is indicated.


Fig. 3.3


The images illustrate lipomatous hypertrophy. Transthoracic echocardiography shows an incidental finding of a large mass at the lateral wall of the right ventricle ( black arrow ). This is lipomatous hypertrophy of the lateral part of the tricuspid annulus, which is a typical finding in the presence of pericardial fluid (Supplementary Video 3.2).




Benign lipomatous tumors of the heart are exceptionally rare. They encompass mainly lipoma and lipomatous hypertrophy of the atrial septum. Cardiac lipomatosis is characterized by the accumulation of nonencapsulated mature adipose tissue caused by hyperplasia of lipocytes. The etiology is unknown, but it may be associated with obesity and advancing age. The most frequent manifestation is lipomatous hypertrophy of the interatrial septum, but massive epicardial lipomatous hypertrophy is less well documented. Although histologically benign, it has been reported to cause cardiac tamponade, requiring decompressive pericardiectomy. Usually, lipomatosis remains asymptomatic and represents an incidental finding on echocardiography. Furthermore, it can be mistaken for other benign or malignant cardiac tumors, leading to unwarranted radical surgical resection ( Supplementary Video 3.2 ).


The usual imaging to evaluate lipomatous hypertrophy is transthoracic and transesophageal echocardiography, where the septum appears unusually thick and spares the membrane of the fossa ovalis. Surgical resection is essentially not necessary and should be reserved for patients who show evidence of right or left outflow obstruction or vena cava superior obstruction .


Fig. 3.4


The images demonstrated a dilated coronary sinus. Transthoracic echocardiography in the systole (A) and diastole (B) of a healthy man shows an incidental finding of a round, echo-free, well-defined, cystic-like mass posterior to the left atrium ( yellow arrows ). This finding is the typical appearance of a markedly dilated coronary sinus, which is mostly due to persistent left superior vena cava (PLSVC). (C) Computed tomography angiography 3D volume-rendered reconstruction shows PLSVC ( white arrow ), which drains into the coronary sinus.




Persistent left superior vena cava (PLSVC) is a rare congenital anomaly; nevertheless, it is the most common abnormality of the thoracic venous system and the commonest cause of a dilated coronary sinus. Two types of PLSVC are known in the literature. In 92% of cases, PLSVC is connected to the right atrium through the coronary sinus without significant hemodynamic consequences, while in 8% of cases, PLSVC connects directly or through the pulmonary veins to the left atrium, causing a right-to-left shunt. It is most commonly an isolated finding but can be associated with other congenital heart defects. PLSVC should be suspected when a dilated coronary sinus is identified via echocardiography. This is often discovered incidentally during an echocardiographic examination or other cardiovascular imaging because it is almost always asymptomatic. Therefore the evidence of a dilated coronary sinus must always be investigated in search of a congenital malformation and especially PLSVC. Usually, agitated saline injected into the brachial left vein drains through the abnormal connection between the left-sided venous return and the coronary sinus, where the bubbles can be clearly seen first in the coronary sinus and the successive opacification of the right atrium. However, considering that physicians should attempt to rule out causes of right atrial pressure/volume overload such as atrial septal defect, coronary fistula, and other anomalous drainage patterns into the coronary sinus, nowadays, multislice computed tomography is more frequently applied by cardiologists and radiologists to visualize the coronary anatomy, coronary anomalies, and aortic pathology .


Fig. 3.5


The images demonstrate a prominent Chiari network. (A) The apical 4-chamber view of transthoracic echocardiography of a healthy man shows a hypermobile net-like mass floating freely in the right atrium. This finding favors a prominent Chiari network; however, pedunculated right atrial tumor, right atrial thrombus, tricuspid valve vegetation, and flail tricuspid valve are in the differential diagnosis. (B) Prominent Chiari network can be seen in the autopsy.

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Nov 10, 2024 | Posted by in CARDIOLOGY | Comments Off on Imaging pitfalls, artifacts, and normal variants mimicking cardiac masses

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