Cardiac and Paracardiac Masses






  • Key Points


  • ▪

    The initial evaluation of cardiac masses should be performed using echocardiography.


  • ▪

    Cardiac CT scanning is able to image cardiac masses and can contribute to their evaluation. The superior field of view of CCT compared with both transthoracic echocardiography and TEE may assist with the assessment of paracardiac masses.


  • ▪

    From the pathology point of view, it is important to recall that imaging and histology are distinct entities.


  • ▪

    The goal of CCT should be to determine whether a mass demonstrates malignant features such as tissue plane violation.


Although CCT is able to image most lesions within the heart, especially larger ones, its role is secondary to those of echocardiography and MRI in the evaluation of lesions within the heart. CCT’s greatest contribution is to evaluate the thorax in detail for complex cardiac masses (both those extending into the heart and those located elsewhere). Neither transthoracic nor transesophageal echocardiography has sufficient field of view to see beyond the heart into the chest cavity or even entirely around the heart. For example, a pericardial cyst often is not apparent by echocardiography (unless the cyst abuts the chest wall).


Lesions that are atypical for myxomas should be further evaluated by CT scanning to ensure that there are no signs of malignant disease elsewhere within the chest or abdomen.


CT scanning is unparalleled in its ability to identify calcification within lesions, such as pericardial masses or thickening.


Although CCT is able to image small and mobile structures within the heart, such as vegetations, echocardiography, by virtue of having vastly superior temporal resolution, is the preferred test for imaging small and mobile lesions within the heart itself. For any mass lesion other than the most obvious myxoma, it would be unwise not to perform a CT scan of the chest and abdomen to exclude signs of malignancy elsewhere.


CCT may assist with surgical planning in cases such as the younger patient with presumed atrial myxoma by confirming lesional characteristics as seen by echocardiography and by excluding significant coronary artery disease.


CCT can image a wide range of intra- and paracardiac structures:



  • □

    Intracardiac masses and lesions



    • •

      Vegetations


    • •

      Thrombi


    • •

      Tumors/masses


    • •

      Abscesses



  • □

    Paracardiac masses and lesions



    • •

      Cysts


    • •

      Tumors/masses






Cardiac Masses


Cardiac masses can be categorized with respect to nature:



  • □

    Thrombus


  • □

    Cysts


  • □

    Abscesses


  • □

    Neoplasms



Thrombus


Thrombus, the most common type of intracardiac mass, is most often located within the left atrial appendage. It is often associated with mitral valve disease and underlying atrial dysrhythmias.


In the left ventricle, thrombi usually are apical in location and usually are associated with prior myocardial infarct. This may occur in an area of associated severe hypokinesis, or within a left ventricular aneurysm. Left ventricular thrombi can be laminar, more rounded and mass-like, or pedunculated. Long-standing thrombi can calcify. Pre–contrast-enhanced and delayed imaging can be used to aid in differentiating between a non-enhancing thrombus and an enhancing tumor.


If a thrombus is suspected within the right atrium, in the absence of an instigating factor such as a central line or pacing wire, one must attempt to exclude tumor or tumor thrombus from an intra-abdominal source such as renal cell carcinoma or hepatocellular carcinoma.


Cysts


Pericardial Cysts


For discussion and examples of pericardial cysts, see Chapter 17 .


Echinococcosis


Echinococcosis of the heart, also known as hydatid disease or echinococccal disease, is the result of parasitic infection with the tapeworm Echinococcus granulosus . The parasite is shared in its life cycle with another mammal such as a dog or sheep, and the disease is endemic in sheep-ranching areas. The incubation period is months to years. Echinococcus eggs lead to the growth of cysts of 5 to10 cm in size that characterize the disease and may involve the heart ( Fig. 23-1 ).




Figure 23-1


Echinococcus of the heart. A, Transthoracic echocardiography in the short-axis view demonstrates the presence of a pericardial cyst in the inferior and posterior basal part of the left ventricle ( red arrows ). B, Contrast-enhanced CT in the axial view demonstrates four pericardial cysts ( red arrows ). C, T2-weighted turbo spin magnetic resonance confirms the liquid nature of the structures by a homogeneous hyperintense signal ( red arrows ).

(Reprinted with permission from Gerber BL, Pasquet A, El Khoury G, et al. Echinococcosis of the heart and ascending aorta. Circulation . 2012;125(1):185-187.)


Abscesses


For a discussion and examples of cardiac abscesses, see Chapter 20 .


Cardiac Neoplasms


Cardiac neoplasms are rare. They include, in order of frequency:



  • 1.

    Metastases (the most common, by 20- to 40-fold)


  • 2.

    Malignant primary neoplasms


  • 3.

    Benign primary neoplasms



In a consecutive autopsy series of 12,485 cases, the prevalence of primary cardiac tumors was 0.056% and of cardiac metastases 1.23%.


Metastases


Metastatic cardiac disease spreads to the heart by four pathways:



  • □

    Retrograde lymphatic extension: lung, breast, lymphoma


  • □

    Hematogenous spread: melanoma, breast, lymphoma


  • □

    Direct contiguous extension: lung, esophagus, breast, lymphoma, thymoma


  • □

    Transvenous extension: kidney, liver (up the inferior vena cava), bronchogenic (down a pulmonary vein)



The most common primary sources for cardiac metastases include lung bronchogenic carcinoma, breast adenocarcinoma, lymphoma, melanoma, and sarcomas ( Figs. 23-2 through 23-6 ).




Figure 23-2


A, Contrast-enhanced CT at the level of the pulmonary arteries. The patient presented with shock and right-sided heart failure. An echocardiogram ( not shown ) had shown a large pericardial effusion, which was drained with only partial improvement. CT scanning shows bilateral effusions and soft tissue masses around the pulmonary arteries as well as soft tissue within the pulmonary arteries. Deep venous thrombosis was present. B, Contrast-enhanced CT at the level of the pulmonary arteries. The right pulmonary artery is nearly entirely obliterated and both bronchi are compressed; the right bronchus is slit-like. The patient’s shortness of breath was multifactorial. C, Contrast-enhanced CT at the level of the liver. The inferior vena cava (IVC) is severely dilated, as are the hepatic veins, and there is reflux into the IVC of contrast dye infused from the upper extremities, consistent with severe right-sided heart failure. There is a rim of ascites. The diagnosis was adenocarcinoma of lung with pleural effusions, tamponade, pulmonary artery obstruction from extrinsic compression, angioinvasion, and pulmonary thromboembolism.



Figure 23-3


Images in a patient with metastatic bronchogenic carcinoma. A, Extensive soft tissue infiltration of the mediastinum. The soft tissue insinuates between the left atrium and the aorta, and courses around the left main and left anterior descending (LAD) arteries. Contrast also is seen within a ramus branch. The circumflex system was patent, but not imaged on this generated maximum intensity projection. Absence of an epicardial fat plane around the coronary arteries is suspicious for invasion of the epicardial fat, and tumor encasement of the coronary arteries. A follow-up study 3 months later demonstrates faint contrast within the proximal portion of the ramus, but occlusion of the ongoing ramus branch. The LAD and circumflex artery show, however, a slightly more irregular appearance. Arterial infarction occurred, believed to be due to coronary artery compression by bronchogenic carcinoma.



Figure 23-4


A, CT image of a 72-year-old man shows a large non-small cell lung carcinoma ( white arrow ) infiltrating the right atrium ( curved arrow ) and the left atrium ( black arrowhead ). B, Transverse CT image of a 63-year-old woman shows a large spiculated mass in the right lower lobe ( white arrow ), pathologically proven to be squamous cell carcinoma, extending to the right atrium ( curved arrow ). There is also a malignant pericardial effusion ( arrowhead ).

(Reprinted with permission from Rajiah P, Kanne JP, Kalahasti V, Schoenhagen P. Computed tomography of cardiac and pericardiac masses. J Cardiovasc Comput Tomogr . 2011;5(1):16-29.)



Figure 23-5


A 62-year-old female dialysis patient presented with intermittent fever, dyspnea, and hoarseness (due to a diagnosed thyroid tumor). While she was treated for fever of unknown origin, transthoracic echocardiography ( A ) showed a solid high-echoic mass ( arrow ) extending into the main pulmonary artery (PA) and obliterating the right ventricular outflow tract. B, C, and D, A 64-multislice CT scan demonstrated a large ellipsoid mass (59 × 55 × 35 mm) extensively involving the right ventricular (RV) wall. Transvenous biopsy confirmed undifferentiated thyroid carcinoma. At 20 days after admission, the patient died of decompensated heart failure. E, An autopsy confirmed the findings of transthoracic echocardiography, multislice CT scan, and the biopsy. Right ventricular outflow tract obstruction from metastatic thyroid cancer is extremely rare. We speculate that the patient’s immunosuppression therapy as well as the fact that she was a dialysis patient may have contributed to the tumor’s progression. LV, left ventricle; RA, right atrium.

(Reprinted with permission from Yanagisawa S, Suzuki Y, Yuasa T, Tanaka T. Right ventricular outflow tract obstruction: metastatic thyroid carcinoma. J Am Coll Cardiol . 2010;55(11):1159.)



Figure 23-6


Multiple images from a CT pulmonary embolism study in a 48-year-old man with prior history of chest wall sarcoma who presented with chest pain and shortness of breath. A, Thinning of the right anterior chest wall from prior tumor resection. The heart appears encased by the pericardium, suspicious for pericardial metastatic disease. B, Marked thickening of the pericardium, with primarily soft tissue attenuation material. C and D, These images have been generated in a lower window width level to better appreciate a large 3.7-cm low-density mass involving the posterior lateral wall of the left ventricle, and extending into the ventricular cavity. This finding is suspicious for a myocardial metastatic deposit.

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Apr 10, 2019 | Posted by in COMPUTERIZED TOMOGRAPHY | Comments Off on Cardiac and Paracardiac Masses

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