CT signs of cardiac arrest with unusual opacification of portal venous system

A 27-year-old patient admitted to the Emergency department with left iliac fossa warm tender swelling, suspecting abscess, and was vitally unstable. After the patient was stabilized, she was referred to Contrast-enhanced CT to aid in the diagnosis.

After intravenous injection of 80 ml of non-ionic iodinated contrast material (Iohexol 300 mg I/ml) at 2.5 ml/s. The portal venous phase images showed contrast in the right atrium, right ventricle, coronary sinus, pulmonary arteries, superior vena cava, inferior vena cava, azygos and hemiazygos veins. No contrast was visualized in the left chambers of the heart or the aorta (Figures 1 and 2).

Contrast was seen in the dependent portion of the abdominal veins, including abdominal IVC, hepatic, renal and lumbar veins (Figures 3 and 4). Contrast was also seen in the dependent portions of the portal venous system, namely portal, splenic and superior mesenteric veins (Figure 5).

The findings were consistent with imminent cardiogenic shock and cardiac arrest.

Contrast-enhanced CT is the core modality in emergency units. Patients are usually vitally stable before imaging, so scanning the patient during cardiac arrest is rare. However, the increasing use of CT to image patients with borderline hemodynamics has increased the occurrence of cardiac arrest during CT scans [1, 2].

The CT findings during cardiac arrest are characteristic. The findings include contrast opacification of the right atrium, superior vena cava (SVC) and inferior vena cava (IVC). Also, opacification of the abdominal veins with radiological signs called “Dense abdominal veins” [3]. Those findings are caused by the loss of the pumping effect of the heart, loss of the arterial and venous pressure and loss of the arteriovenous gradient. Therefore, the contrast is being pushed by pressure of the contrast injector only [1, 4]. Although reflux to the IVC is seen in some cases of tricuspid regurgitation or congestive cardiac failure, in case of cardiac arrest, the radiological sign of “dependent pooling” is noticed because of loss of the cardiac pumping function. The contrast being heavier than the blood, is seen in the dependent part of the vessels because of gravity [1]. Also, in hypovolemic shock, the IVC is usually collapsed but in cardiac arrest cases, including our case, the IVC didn’t decrease in size due to the reflux of contrast into the IVC [5].

Portal, superior mesenteric and splenic veins opacification is a rare finding, and splenic vein opacification was reported in only a few cases in the literature [1, 2, 4, 5]. Our case here shows opacification of those veins. The cause of this sign is not fully understood. It has been hypothesized the contrast reaching the right lobe of the liver through the IVC and hepatic veins causes retrograde filling of the portal vein through sinusoidal communication in the hepatic parenchyma [1, 4]. This hypothesis is supported by the presence of pooling of contrast in the right lobe of the liver in all the cases showing portal vein opacification. The presence or absence of pooling of contrast in the liver and portal vein retrograde filling could be attributed to the duration from cardiac arrest till the CT scan and the injector pressure [1, 2, 4].

Imminent cardiogenic shock and cardiac arrest during CT scanning have characteristic radiological signs. It is crucial that all healthcare taskforce know those signs to start immediately cardiopulmonary resuscitation to reduce morbidity and mortality.

Written informed patient consent for publication has been obtained.