Intracardiac thrombi

Dr Owen Kang and Radswiki et al.

Intracardiac thrombi are seen in a variety of clinical settings and can result in severe morbidity or even death from embolic events. They can occur following myocardial infarction with ventricular thrombus formation, or with atrial fibrillation and mitral stenosis where atrial thrombi predominate.

Thrombi in the chambers of the left heart are a common source of complications like stroke and other arterial embolic syndromes.

Transthoracic echocardiography is the diagnostic tool of first choice, however, the inability to visualise all cardiac chambers and the reduced image quality in some patients are limitations of transthoracic echocardiography. Therefore, transesophageal echocardiography has emerged as the most sensitive modality for the detection of intracardiac thrombi.1

The lack of enhancement differentiates cardiac thrombus from other cardiac tumours.

Cine images using steady state free precession (SSFP) allow the localisation of the thrombus and targets subsequent sequences to the region of interest. Cine images can also demonstrate segmental hypokinesia in surrounding infarcted myocardium. On cine images, thrombus can sometimes be difficult to separate from the adjacent myocardium if they have similar intensity, and can be readily missed unless gadolinium is administered.

In this sequence, the heart is imaged at every heart beat following pump injection of gadolinium. This allows dynamic imaging of contrast as it passes from the right ventricle, into the left ventricle, into the myocardium, and following redistribution. Thrombus being an avascular lesion will be of homogenous low intensity on every phase.

A long inversion time of ~440 ms is chosen to null any non-vascular lesions (eg thrombus) that do not contain gadolinium. This accentuates thrombus by making it very hypointense compared to surrounding tissues which contain gadolinium. Any lesion which is not homogenously hypointense points to an alternative pathology.

A short inversion time is initially chosen to null the gadolinium-rich myocardium, so that any areas of myocardial enhancement are accentuated. The initial inversion time is decided upon by performing a scout at different TI, and choosing the TI which nulls the myocardium. This also incidentally results in some fat suppression as fat has a short T1 value (~150 ms). The inversion time is progressively increased as late gadolinium imaging progresses, because gadolinium washes out of the myocardium, and the T1 value increases back to baseline. Thrombus will remain of low intensity, and any underlying infarct will be revealed by sub-endocardial enhancement.

The biggest risk from cardiac thrombus is distal embolisation, resulting in stroke, visceral infarction or distal limb ischaemia. Treatment is anticoagulation.

For a mass in the cardiac chambers consider:

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Article information

rID: 12660
System: Cardiac
Synonyms or Alternate Spellings:
  • Intra-cardiac thrombus
  • Intra-cardiac clot
  • Intracardiac thrombus
  • Intra-cardiac thrombi
  • Intra cardiac thrombus
  • Intra-cardiac blood clot

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Cases and figures

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    Case 1: in left ventricle
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    Short axis view
    Case 2: left atrium + ventricle
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    Case 3: in right atrium
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    Case 4
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    Case 5: in left atrial appendage
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    Case 6: in right atrium
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