Presentation
Fall but unable to give a lucid history of events. Now decreased GCS. Left iliac fossa tenderness/guarding; severely dehydrated; elevated inflammatory markers and respiratory acidosis. Septic.
Patient Data
On putative arterial and portal venous phases, concentrated contrast medium lies in the right subclavian vein, azygos arch, azygos vein, right atrium, with reflux into the coronary sinus, infrahepatic IVC, middle/right hepatic veins and multiple hepatic venous tributaries throughout the posterior peripheral liver, and also into the right renal vein and its intrarenal tributaries. Contrast in the left atrium from a direct interatrial communication between the two atria via a septal opening, ASD vs PFO. Small amount of contrast medium also in the left ventricle. Contrast medium also extends from the left atrium into several pulmonary veins.
No contrast medium in the pulmonary arteries, aorta or arterial side of the systemic circulation.
Further meaningful evaluation of the hepatic lesion cannot be performed.
Interval enlargement moderate right pleural effusion and very small left-sided effusion with bilateral atelectasis and subtotal consolidation of the right lower lobe. Suspicion of pulmonary honeycombing.
Conclusion:
Cardiac arrest during a CT results in this characteristic pattern of contrast opacification secondary to reflux into the IVC and also into the left atrium ? PFO.
Case Discussion
This case is a rare example of the CT findings of a cardiac arrest.
This CT liver was performed as a standard 3-phase protocol following an unshown study from the day before that demonstrated an indeterminate liver lesion for which further characterization was suggested (hepatic abscess versus metastasis).
The two series shown here were supposed to be arterial and portal venous phases, indeed the second series was performed 40 s after the first series (itself performed 20 s post injection). However, due to the absence of a functioning circulatory pump due to the cardiac arrest, there is almost no movement of the IV contrast agent within the elapsed 40 seconds.
The case is a good illustration of the contrast agent pooling (CAP) sign that has been shown to be a marker of imminent cardiac arrest and an extremely poor prognosis. Other CT signs of arrest that it shows are IV contrast agent vascular reflux and the IVC level sign.
Unusually, this patient demonstrated dense contrast in the left atrium, less so in the left ventricle and aorta, without contrast opacification of the pulmonary arterial tree. This is indicative of a right to left shunt, in this case at the level of the atrium.
This particular patient did not recover following his arrest in the CT suite despite intensive efforts from the cardiac arrest team.
Cardiac arrest is of course usually diagnosed clinically, however occasionally a patient will be periarrest or will have arrested just prior to, or even during, an imaging exam as was the case here. In this case, it was the senior CT radiographer who paged the arrest team.
Described CT features in the arrest/periarrest patient cohort include 1,2:
- contrast agent pooling sign
- IV contrast agent vascular reflux into
- absence of contrast media in the pulmonary arteries, aorta and left heart
-
IVC level sign: blood-dependent contrast level in venae cavae due to stasis of contrast media
- may be seen in non-arrest scenarios, e.g. hypovolemic shock
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