Non-coronary abnormalities of the left heart: CT angiography findings

Abstract

Cardiac computed tomography (CT) is most commonly performed for the evaluation of the coronary arteries; however, non-coronary cardiac pathologies are frequently detected on these scans. In cases where magnetic resonance imaging cannot be used, cardiac CT can serve as the first-line imaging modality to evaluate many non-coronary cardiac pathologies. In this article, we discuss congenital non-coronary abnormalities of the left heart and their cardiac CT imaging features.

Figure 1

If a septal defect cannot be directly visualized due to its small size, a contrast jet (arrow) from the opacified left into the unenhanced right atrium will establish the diagnosis like in this patient

Figure 2

Primum atrial septal defect. Axial coronary CT angiography shows that the interatrial septum does not extend to the junction of the mitral and tricuspid valves, resulting in a defect (arrow) in the basal part of the septum. Note the thin septum in the fossa ovalis (arrow head) which should not be misinterpreted as a secundum ASD

Figure 3

A 68-year-old woman with secundum atrial septal defect. Axial coronary CT angiography image shows a large, incidentally detected defect (arrow) at the midportion of the interatrial septum

Figure 4

(a) Axial MIP coronary CT angiography image shows a connection (arrow) between two atria at the level of the opening of the superior vena cava (SVC) to the right atrium. (b) A right pulmonary vein drains into the SVC (known as partial anomalous pulmonary venous return) in the same patient

Figure 5

Coronary sinus type ASD. Normally, the coronary sinus (CS) is located along the posterior wall of the left atrium and drains into the right atrium (RA). In this case, MPR coronary CT angiography image shows a defect (arrow) between the roof of CS and left atrium (LA)

Figure 6

A variant of coronary sinus type ASD. (a) MPR coronary CT angiography image shows a defect (arrow) between the roof of coronary sinus and left atrium. (b) Axial coronary CT angiography image shows atresia of coronary sinus orifice (arrow head) in the same patient

Figure 7

(a, b) The patient with superior sinus venosus type ASD (arrow head) also has a secundum ASD (arrow). Cases with more than one type of ASD are called complex ASD

Figure 8

Patent foramen ovale. (a) Axial and (b) sagittal coronary CT angiography images show the lack of fusion between septum primum (black arrow) and secundum (white arrow) with a contrast-filled channel between them. The direction of the channel is towards the inferior vena cava (IVC). A contrast jet (arrow head) through the gap in the interatrial septum from the left to the right atrium is present

Figure 9

Coronary CT angiography image shows fusion of the septum primum and secundum in the inferior part (arrow head), and lack of fusion in the proximal part (arrow). In this case, a contrast-filled tunnel in the interatrial septum exists; however, a contrast jet to the right atrium does not occur. This entity is referred as probe patent foramen ovale

Figure 10

Interatrial septal aneurysm. (a) Coronary CT angiography image shows protrusion (more than 10 mm) of the interatrial septum into the right atrium. (b) In the same patient, a small defect (arrow) in the interatrial septum (secundum atrial septal defect) is also observed

Figure 11

(a) Coronary CT angiography image shows a diverticulum (black arrow) with a wide neck and smooth contours projecting outward from the inferior part of the left atrium wall. (b) Multiple left atrial diverticula (white arrows) are seen in a different patient

Figure 12

Coronary CT angiography image shows accessory left atrial appendage (arrow head) in addition to the normal left atrial appendage (arrow). Note the narrow neck and internal trabeculation of the accessory appendage

Figure 13

Coronary CT angiography image shows the co-existence of an accessory left atrial appendage (arrow) and left atrial diverticulum (arrow head) in the same patient. Left atrial diverticula have a wider neck and smoother contours compared to accessory left atrial appendages

Figure 14

Coronary CT angiography images show a thin membrane (arrows), which divides the left atrium into two compartments in a patient with cor triatriatum

Figure 15

Type 2 ventricular septal defect (VSD). Coronary CT angiography image shows a defect (arrow) in the membranous septum. This condition is referred as partially closed membranous VSD

Figure 16

Axial and sagittal coronary CT angiography images show protuberance of the interventricular septum into the right ventricle (arrows) in the location of the membranous septum. This condition is termed a ventricular septal aneurysm and is related to the spontaneous closure of a perimembranous ventricular septal defect

Figure 17

Type 3 (inlet type) ventricular septal defect (VSD). Coronary CT angiography image shows a VSD (arrow) at the inlet septum beneath the septal leaflet of the tricuspid valve (TV) (MV-mitral valve)

Figure 18

Type 4 ventricular septal defect. Coronary CT angiography image shows a defect (arrow) in the apical segment of the muscular interventricular septum

Figure 19

Coronary CT angiography image shows a ventricular cleft (arrow) in the interventricular septum of the left ventricle

Figure 20

Coronary CT angiography image shows multiple ventricular clefts (arrow) in the interventricular septum, which are connected to the left ventricle

Figure 21

Coronary CT angiography image shows a diverticulum (arrow) in the apical segment of the left ventricle in a patient with hypertrophic cardiomyopathy. A very thin left ventricular myocardium confining the diverticular sac is observable

Figure 22

Coronary CT angiography image shows that the ratio of non-compacted myocardium (NCM) to compacted myocardium (CM) is approximately 2.5 in the left ventricle in a patient with left ventricular non-compaction