Cardiac Masses on Cardiac CT: A Review
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Cardiac masses are rare entities that can be broadly categorized as either neoplastic or non-neoplastic. Neoplastic masses include benign and malignant tumors. In the heart, metastatic tumors are more common than primary malignant tumors. Whether incidentally found or diagnosed as a result of patients’ symptoms, cardiac masses can be identified and further characterized by a range of cardiovascular imaging options. While echocardiography remains the first-line imaging modality, cardiac computed tomography (cardiac CT) has become an increasingly utilized modality for the assessment of cardiac masses, especially when other imaging modalities are non-diagnostic or contraindicated. With high isotropic spatial and temporal resolution, fast acquisition times, and multiplanar image reconstruction capabilities, cardiac CT offers an alternative to cardiovascular magnetic resonance imaging in many patients. Additionally, cardiac masses may be incidentally discovered during cardiac CT for other reasons, requiring imagers to understand the unique features of a diverse range of cardiac masses. Herein, we define the characteristic imaging features of commonly encountered and selected cardiac masses and define the role of cardiac CT among noninvasive imaging options.
KeywordsCardiac computed tomography Coronary computed tomographic angiography Cardiac mass Neoplasm Tumor Myxoma Lipoma Teratoma Sarcoma Metastasis Thrombus Pericardial cyst
Cardiac neoplasms and commonly-encountered non-neoplastic masses
Atrioventricular (AV) nodal mesothelioma
Lipomatous hypertrophy of interatrial septum
Large coronary artery aneurysm
Imaging Approach to Cardiac Masses
Cardiac CT features of benign and malignant tumors
Small (<5 cm), single lesion
Large (>5 cm), multiple lesions
Left > > right
Right > > left
Narrow stalk, pedunculated
Absent to minimal
Modest to intense
May be present
May be present
Rare (except for small foci in fibroma, myxoma, or teratoma)
Large foci in osteosarcoma
Recommendations for the use of noninvasive imaging to evaluate suspected cardiac and pericardial masses
2006 Appropriate use criteria for cardiac MRI 
- Evaluation of cardiac mass (suspected tumor or thrombus) ……… Appropriate
- Evaluation of pericardial mass ……………………………………. Appropriate
2010 Appropriate use criteria for cardiac CT 
- Initial evaluation of cardiac mass (suspected tumor or thrombus) … Inappropriate
- Evaluation of cardiac mass (suspected tumor or thrombus) [when] inadequate images from other noninvasive methods …….… Appropriate
- Evaluation of pericardial anatomy………………………………….. Appropriate
2013 Expert consensus for pericardial disease imaging [7••]
- “Echocardiography is the initial imaging test to assess pericardial masses”
- “CT and/or MRI should be done for better tissue characterization of the mass and detection of metastasis (if malignancy is suspected).”
Cardiac CT is an alternative imaging modality to assess cardiac masses, particularly in patients with known contraindications to MR or in patients with inadequate images from other noninvasive methods. Cardiac CT is a fast imaging technique with electrocardiographic (ECG) gating that provides high quality images with superior spatial resolution. Electrocardiographic gating minimizes motion-related artifacts and allows a more precise delineation of the lesion margins. Compared to other cardiac imaging modalities, CT is optimal for the evaluation of calcified masses, the global assessment of the chest and lung tissue and corresponding vascular structures, and the exclusion of obstructive coronary artery disease or masses which involve the coronary arteries. Significant disadvantages with CT include radiation exposure, a small risk of contrast-induced nephropathy, and lower soft tissue and temporal resolutions as compared with magnetic resonance imaging.
Cardiac CT is also useful to detect metastases in suspected malignancies especially when coupled with 18 F-fluorodeoxyglucose (FDG) positron emission tomography (PET). The ability of 18 F-FDG PET/CT to detect the increased metabolism of glucose may help distinguish malignancy from a benign neoplasm. For example, primary malignant cardiac tumors and metastatic tumors show significantly higher glucose uptake as quantified by 18 F-FDG PET/CT standardized uptake value (SUV) than primary benign cardiac tumors. This differentiation may improve the detection of distant metastases, especially when the results will be used to impact therapy [9•].
Cardiac CT features of primary cardiac tumors
Cardiac CT findings
Benign (75 %)
LA > RA, ventricles
Pedunculated, mobile, heterogeneous, low attenuation, 10 % calcified; may prolapse through the mitral valve
Smooth, encapsulated, fat attenuation, no enhancement; multiple lesions may be seen with tuberous sclerosis
Small (10 mm), smooth, pedunculated, mobile
LV > RV
Smooth, multiple, attenuation similar to myocardium; > 90 % in infants and children
LV > RV
Homogenous, low attenuation, minimal enhancement, central calcification; second most common in infants and children
LV > RV
Heterogeneous, intense enhancement
Multicystic, moderate enhancement, partially calcified
Malignant (25 %)
RA > RV, pericardium
Broad base, irregular, heterogeneous, low attenuation, infiltrative, pericardial effusion, metastatic
Irregular, low attenuation, infiltrative; most common in infants and children
Large, irregular, low attenuation, central necrosis, infiltrative
LA > RA, RV
Broad base, low attenuation, infiltrative, extensive calcification
LA > RA, pericardium
Large, fat and soft tissue attenuation, mild contrast enhancement, infiltrative
Infiltrative, variable attenuation, pericardial effusion
Benign Cardiac Neoplasms
Carney complex: multiple recurrent cardiac and mucocutaneous myxomas, pigmented skin lesions, schwannomas, and endocrine overactivity neoplasms.
LAMB: Lentigines, Atrial Myxoma, and Blue nevi.
NAME: Nevi, Atrial myxoma, Myxoid neurofibroma, and Ephelides.
Malignant Cardiac Neoplasms
Malignant cardiac tumors are most often a result of metastatic disease arising by direct extension of adjacent organs or spread via hematogenous, lymphatic, or intracavitary routes . The most common malignancies metastatic to the heart originate from the lung (35-40 %), followed by breast (10 %) and hematologic (10-20 %) carcinomas. Melanoma has the greatest propensity to metastasize to the heart, but it is often found late in the disease process [18•]. Other primary sites of origin include renal, hepatic, adrenal, and thyroid. The most frequent location of metastasis is the pericardium (65-70 %), followed by epicardium (25-35 %) and myocardium (30 %). Endocardial or intracavitary involvement is rarely observed (3.5 % of cases) [18•].
Cardiac CT offers several advantages for the evaluation of metastatic cardiac involvement. Primarily, cardiac CT offers the ability to image direct tumor extension and extracardiac involvement with both three-dimensional reconstruction capability and superior spatial resolution. On cardiac CT, pericardial metastasis can appear as pericardial thickening, disruption, or effusion. Myocardial involvement typically demonstrates thickening and nodularity. Solid tumors often demonstrate enhancement following the administration of intravenous contrast.
Angiosarcoma is the most common primary cardiac malignant tumor and is comprised of cells that develop multiple, irregular vascular channels. The primary site of origin is the right atrial free wall in 80 % of cases and less commonly the right ventricle or pericardium . The tumor morphology typically consists of a large, multilobar mass with a heterogeneous composition that spreads along the epicardial surface and replaces the right atrial wall. Given the bulky nature, the tumor may comprise the majority of the right atrium and involve the right coronary artery leading to rupture . These tumors may also be localized to the pericardium and often invade adjacent cardiac structures leading to cardiomegaly and recurrent pericardial effusions .
Rhabdomyosarcoma is the second most common primary malignant tumor. It accounts for 4-7 % of cardiac sarcomas and remains the most common pediatric cardiac malignancy . It is a malignant tumor of striated muscle that always involves the myocardium. In contrast to angiosarcomas, rhabdomyosarcomas may arise from any location with no predilection for a specific cavity as 60 % of cases involve multiple sites of origin . Additionally, the tumors may invade the pericardial space with a characteristic nodular appearance .
Non-Neoplastic Cardiac Masses
Lipomatous Hypertrophy of the Interatrial Septum
Although there is no definitive diagnostic criteria for the diagnosis of LHIAS, an interatrial septal thickness >20 mm is often used, while a septal thickness exceeding 30 mm may have a greater association with supraventricular arrhythmias . It is important to note that areas of lipomatous hypertrophy contain brown fat and, therefore, may appear as FDG-avid (“hot”) on PET scans. Though rare, liposarcoma should be considered as a differential diagnosis, especially when intra-mass calcification or enhancement is present or in cases with rapid growth and involvement beyond the interatrial septum. Other causes of fat containing cardiac lesions include fatty metaplasia due to remote myocardial infarction, cardiac lipoma and arrhythmogenic right ventricular cardiomyopathy/dysplasia.
Thrombus accounts for the most commonly encountered intracardiac mass . It can occur in any of the cardiac chambers, though it most often involves the left-sided structures. Thrombus formation can be caused by hypercoagulable states, systolic dysfunction with wall motion abnormalities, atrial fibrillation, or artificial devices. It typically appears as a hypodense, low-attenuation filling defect in a contrast pool within a cardiac chamber and may be differentiated from primary and secondary tumors by knowledge of predisposing risk factors, attachment location, shape, and lack of mobility [29•].
Cardiac CT has very high sensitivity for excluding thrombus of the left atrial appendage but findings of low attenuation in the left atrial appendage (LAA) are not specific to thrombus as this often represents circulatory stasis, an incomplete mixing of contrast material and blood. This “pseudo” filling defect may mimic thrombus, especially in low-flow states [30•]. However, delayed imaging of the LAA may significantly improve the specificity to distinguish thrombus from circulatory stasis . For example, a ratio of LAA attenuation to the ascending aorta > 0.75 on delayed cardiac CT images performed 30 seconds following first-pass contrast imaging can help differentiate thrombus from circulatory stasis with a high negative predictive value .
In summary, cardiac CT can provide useful anatomic and functional information as an adjunct to echocardiography and MR in the evaluation of cardiac masses. With high spatial and contrast resolution, fast acquisition times, and the capability to identify calcification and fat, cardiac CT can serve as an ideal alternative to MR imaging, especially in patients with contraindications. Furthermore, cardiac CT may have specific advantages in defining the cardiovascular extent of the mass and excluding coronary artery disease prior to surgical intervention. With the continued, widespread utilization of cardiac CT, it is important to accurately distinguish cardiac masses in order to provide optimal medical management.
Compliance with Ethics Guidelines
Conflict of Interest
David Kassop, Michael S. Donovan, Michael K. Cheezum, Binh T. Nguyen, Neil B. Gambill, Ron Blankstein, and Todd C. Villines declare that they have no conflict of interest.
Human and Animal Rights and Informed Consent
This article does not contain any studies with human or animal subjects performed by any of the authors.
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