Multidetector Computed Tomographic Characterization of a Left Atrial Myxoma

A 57-year-old woman presented to her local hospital with left arm and leg weakness and was diagnosed with a right-sided stroke. A subsequent transthoracic echocardiogram showed a large, poorly-defined mass within the left atrium, which prompted her transfer to our institute for urgent surgical resection.

As a prelude to surgery, we performed a "tripartite" coronary CT angiogram to assess the coronary anatomy and left atrial mass (Figure 1). The findings were consistent with a left atrial myxoma and the patient subsequently underwent surgery, where the mass was resected and the diagnosis substantiated (Figure 2).

Figure 1.

ECG-gated cardiac computed tomography. Figure 1a shows a large mass (arrow) occupying one third of the left atrium in systole (40% phase). Figure 1b shows the mass (arrow) prolapsing through the mitral valve into the left ventricle in diastole (90% phase). On first pass perfusion (FPP) imaging (Figure 1c) the mass was shown to be hypoattenuated (52 HU) when compared to the myocardium (140 HU) indicating reduced vascularity. Figure 1d shows a lack of delayed enhancement (DE) on an interval scan performed 7 minutes later in keeping with the benign nature of the myxoma.

Figure 2.

Macroscopic appearance of the left atrial myxoma following surgical resection. Figure 1a shows the ventricular surface of the myxoma along with the atrial septum and Figure 1b the ventricular surface.

Myxomas have an estimated incidence of 0.007%. Although echocardiography remains the first-line investigation to establish their diagnosis, the current case highlights the typical appearances and usefulness of CT as a second-line investigation when further information is required.