A 72–year–old man with a history of resected multicentric ileal carcinoid tumor underwent evaluation for small bowel obstruction (SBO). A newly elevated urinary 5–hydroxyindoleacetic acid level prompted a single–photon emission computed tomography/computed tomography (SPECT/CT) octreotide scan which revealed intense radiotracer uptake in the cardiac apex. A transthoracic echocardiogram (TTE) revealed no valvular abnormalities or intracardiac mass. However, the addition of lipid microsphere intravenous (IV) contrast revealed a pedunculated, 0.75 cm x 0.95 cm mass arising from the myocardium at the RV apex which was confirmed by cardiac MRI.
Although metastatic endocardial implantation of carcinoid tumors is rare, the reported morbidity and mortality is high and underscores the need for a thorough cardiac evaluation. Adjuncts have been sought to increase the diagnostic yield of conventional TTE in the assessment and characterization of intracardiac masses. One promising approach involves the addition of IV contrast enhancement to 2–D echocardiography. Modern contrast agents employ a shell of lipids, albumin, or galactose that prolongs the intravascular lifespan and enables left ventricular assessment. Scaling and subtraction of microbubble acoustic signals from tissue acoustic signals results in selective microbubble detection [4, 5]. The resulting ventricular opacification delineates ventricular borders and increases the number of visualized ventricular segments. In a prospective study comparing conventional TTE and CE in the initial evaluation of 31 patients with an intracardiac mass, CE correctly identified 100% of intracardiac masses (versus 76% with TTE) and enabled visualization of 99% of left ventricular segments (versus 91% with TTE) . CE has also been shown to reliably differentiate between tumor, myxoma, and thrombus [6, 7]. Furthermore, the use of contrast may improve the diagnostic yield in up to 90% of initially nondiagnostic echocardiograms . Recently, fusion of 18F–dihydroxy–phenylalanine (18F–DOPA) PET and MRI has been shown to be of additional diagnostic value in the work up of metastatic carcinoid disease . Like those authors, we initiated the work–up with a TTE which was nondiagnostic, and ultimately employed MRI for its superior resolution. Unlike our colleagues, however, we successfully utilized CE which allowed rapid visualization of an intracardiac mass and correlated favorably with MRI.
Given the availability, patient compliance, and comparatively low cost of cardiac ultrasonography, the addition of IV contrast enhancement may obviate the need for more advanced and costly imaging modalities, such as PET and MRI, in the evaluation of intracardiac masses. In our case, lipid microsphere CE performed comparably to contrast MRI and allowed the rapid visualization of a small, poorly defined cardiac mass.