Cardiac masses & sources of embolism
Thrombus, tumour, vegetation or normal variant — location, attachment, mobility, perfusion and context.
Numbers to remember
- Most common: thrombus > metastasis > primary tumour (myxoma, fibroelastoma) [176]
- Contrast perfusion: tumour enhances, thrombus does not [176]
- LV thrombus: apex after anterior MI or in DCM → contrast when image quality is limited [140]
- LAA thrombus needs TOE; TTE cannot exclude it [176]
Questions echo must answer
A cardiac mass is almost always one of five things: thrombus, vegetation, tumour, normal variant or artefact [176]. Context (AF, akinetic segments, fever, malignancy) is often more informative than appearance.
- Is it real?Seen in two orthogonal views, with defined borders, moving with the structure. Not an artefact.
- Normal variant?Eustachian valve, Chiari network, crista terminalis, LAA pectinate muscles, warfarin (coumadin) ridge, moderator band, false tendons, lipomatous hypertrophy of the atrial septum (spares the fossa ovalis) [176].
- Location and attachmentChamber, stalk or broad base, valvular or mural.
- BehaviourMobility, prolapse through a valve, obstruction [176].
- Tissue characterContrast perfusion; CMR for tissue characterisation [176].
Acquisition protocol
- All windowsSize (three dimensions), attachment point, mobility and relation to valves.
- Colour and CWObstruction (functional MS from a prolapsing myxoma: mean gradient) [6].
- ContrastUltrasound-enhancing agent to define LV apical thrombus and to assess perfusion [140,176].
- ContextLV wall motion (akinetic apex), LA size and rhythm, valve disease, pericardial effusion (malignancy).
- SalineIf a paradoxical embolus or right-to-left shunt is suspected [176].
- TOEFor LAA thrombus, small valvular masses and the atrial septum [35,176].
- Real mass (two views)
- Normal variant excluded
- Location and attachment
- Size (three dimensions) and mobility
- Obstruction
- Contrast perfusion
- Context (wall motion, rhythm, fever, cancer)
- CMR / CT / TOE recommended
Diagnosis & severity
| Mass | Typical features [176] |
|---|---|
| LV thrombus | Apex, adjacent to akinetic segment; laminar or protruding; no perfusion with contrast [140] |
| LA / LAA thrombus | AF, mitral stenosis, low LAA velocities, spontaneous echo contrast; TOE |
| Myxoma | LA, stalk on the fossa ovalis, gelatinous and mobile, may prolapse into the LV; heterogeneous perfusion |
| Papillary fibroelastoma | Small (usually <1.5 cm), on valves (aortic most often), frond-like, mobile stalk; embolic |
| Lipoma / lipomatous IAS hypertrophy | Homogeneous, dumbbell-shaped IAS sparing the fossa ovalis |
| Metastasis / malignant tumour | Broad-based, infiltrating, multiple; pericardial effusion; vascular enhancement |
| Vegetation | Upstream side of valve, oscillating, with regurgitation and infection [136] |
| Thrombus in transit | Worm-like, highly mobile, in RA or RV; associated with PE [124] |
Thresholds that change management
- Myxoma → surgical excision promptly because of embolic and obstructive risk [176].
- Papillary fibroelastoma → surgery if embolic, mobile or large (especially left-sided); otherwise follow-up [176].
- LV thrombus → anticoagulation and re-imaging at about 3 months [140].
- Thrombus in transit → emergency treatment of the associated PE (thrombolysis or embolectomy) [124].
- Indeterminate mass → CMR (tissue characterisation, perfusion, LGE), CT and PET if malignancy is suspected [176].
- Cryptogenic stroke → search for LAA thrombus, PFO and atrial septal aneurysm, aortic arch atheroma and valvular sources (see the Stroke presentation) [176,197].
Pitfalls & mimics
PitfallThe apex in apical views is the commonest place for a near-field artefact that looks like thrombus. Change the depth, frequency and window, and use contrast [140].
- Pectinate muscles in the LAA and the warfarin ridge are mistaken for thrombus on TOE.
- A prominent Eustachian valve or Chiari network in the RA mimics thrombus or vegetation.
- Lipomatous hypertrophy of the IAS can be very thick but spares the fossa ovalis; it is benign.
- Hiatus hernia compresses the LA from behind and looks like an LA mass. Give a fizzy drink to confirm.