CT Case 009

There is a saddle pulmonary embolism, with extension of embolus into the lobar and segmental branches of all lobes.

The right ventricle is dilated.

There is evidence of IV contrast reflux into the IVC. The pulmonary trunk is borderline dilated (at 29mm)

There is a small pulmonary infarct in the right base.

This is a case of a submassive pulmonary embolism.

Submassive pulmonary embolus (PE) is an acute PE without systemic hypotension (SBP ≥90 mm Hg) but with either right ventricle (RV) dysfunction or myocardial necrosis.

The most obvious sign of right heart strain we see on this CT is the large right ventricle (RV). In a CT of a normal heart the RV is smaller than the left ventricle (LV), however here the RV:LV ratio is >1 consistent with right heart strain.

We also see flattening of the interventricular septum as the elevated right sided pressures cause it to be pushed into the left ventricle. In a normal heart we expect to see the septum bowing into the RV instead.

Other features of RHS we see on this CT are contrast reflux into the IVC. This also is due to elevated pulmonary pressures which push contrast media backwards into the IVC.

Lastly, the pulmonary artery is borderline dilated, also due to the high pulmonary pressures caused by the extensive clot burden.

Outcome

This patient was managed with a heparin infusion and eventually transitioned onto oral anticoagulation.

Lower limb doppler confirmed bilateral lower limb DVT.

Follow-up included serial monitoring of d-dimer, which can be used as a surrogate measurement of clot burden.

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