Dependent layering of venous refluxed contrast: A sign of critically low cardiac output

Pseudothrombosis due to blood-contrast level in the infrarenal vena cava

Filling defects within the inferior vena cava (IVC) are common findings on computed tomography (CT); nevertheless, a majority of these defects are attributed to artifacts. The documentation pertaining to pseudothrombosis specifically affecting the infrarenal vena cava is notably insufficient in current literature. The aim of this study is to present a case demonstrating a blood-contrast level in the infrarenal vena cava, resembling an intraluminal filling defect.

Multidetector CT Imaging Biomarkers as Predictors of Prognosis in Shock: Updates and Future Directions

A severe mismatch between the supply and demand of oxygen is the common sequela of all types of shock, which present a mortality of up to 80%. Various organs play a protective role in shock and contribute to whole-body homeostasis. The ever-increasing number of multidetector CT examinations in severely ill and sometimes unstable patients leads to more frequently encountered findings leading to imminent death, together called "hypovolemic shock complex". Features on CT include dense opacification of the right heart and major systemic veins, venous layering of contrast material and blood, densely opacified parenchyma in the right hepatic lobe, decreased enhancement of the abdominal organ, a dense pulmonary artery, contrast pooling in dependent lungs, and contrast stasis in pulmonary veins. These findings are biomarkers and prognostic indicators of paramount importance which stratify risk and improve patient outcomes. In this review, we illustrate the various CT patterns in shock and review the spectrum and prognostic significance of thoraco-abdominal vascular and visceral alarming signs of impending death with the intention of increasing awareness among radiologists and radiographers to prepare for immediate resuscitation when required.

Contrast Agent Pooling (C.A.P.) sign and imminent cardiac arrest: a retrospective study

BACKGROUND

The sign of contrast agent pooling (C.A.P.) in dependent part of the venous system were reported in some case reports, which happened in the patients before sudden cardiac arrest. Until now, there is no solid evidence enough to address the importance of the sign. This study aimed to assess the accuracy of the C.A.P. sign in predicting imminent cardiac arrest and the association of the C.A.P. sign with patient's survival.

METHODS

This is a retrospective cohort study. The study included all patients who visited the emergency department, who received contrast computed tomography (CT) scan and then experienced cardiac arrest at the emergency department (from January 1, 2016 to December 31, 2018). We evaluated the occurrence of the C.A.P. sign on the chest or abdominal CT scan, patients with ECMO were excluded. With positive C.A.P. sign, the primary outcome is whether in-hospital cardiac arrest happens within an hour; the accuracy of C.A.P. sign was calculated. The secondary outcome is survival to discharge.

RESULTS

In the study, 128 patients were included. 8.6% (N = 11) patients had positive C.A.P. sign and 91.4% (N = 117) patients did not. The accuracy of C.A.P. sign in predicting cardiac arrest within 1 h was 85.94%. The C.A.P. sign had a positive association with IHCA within 1 h after the CT scan (adjusted odds ratio 7.35, 95% confidence interval [CI] 1.27 - 42.69). The relative risk (RR) of survival to discharge was 0.90 with positive C.A.P. sign (95% CI 0.85 - 0.96).

CONCLUSIONS

The C.A.P. sign can be considered as an alarm for imminent cardiac arrest and poor prognosis. The patients with positive C.A.P. sign were more likely to experience imminent cardiac arrest; in contrast, less likely to survive.

TRIAL REGISTRATION

IRB No.108107-E.

A survival after cardiac arrest during CT scan: The critical imaging findings

It obtains infrequently hemodynamic images of patients undergoing impending cardiac arrest. Heart pump failure causes blood stasis in the venous system and organs, which is demonstrated on imaging by the deposition and layering of contrast in the veins. We present a case of a multi-trauma patient undergoing imminent cardiac arrest during computed tomography scan under sedation. Signs of early cardiac arrest were immediately found during the examination, including contrast pooling in the inferior vena cava and hepatic veins, poor opacification of the left heart chambers and the aorta. Fortunately, the patient was quickly resuscitated, and his heart pump returned to normal. Although cardiac arrest on computed tomography scan is extremely rare, detecting imaging signs of this situation helps patients receive timely resuscitation and better survival.

Effects of Sedation by Intramuscular Administration of Medetomidine on Canine Abdominal Vascular System and Hepatic Parenchyma Imaging Using Enhancement Dynamic Computed Tomography

This prospective crossover study compared the effects of intramuscular administration of medetomidine for sedation on parameters of the abdominal vascular system, measured by enhancement computed tomography (CT), to those of propofol-induced sevoflurane maintenance anesthesia, as a control, in five clinically healthy adult male beagle dogs (11.4–12.8 kg). Each animal underwent both protocols at a 1-week interval. The enhancement (HU) and time to peak enhancement on CT were measured for the aorta (AO), caudal vena cava (CVC), portal vein (PV), and hepatic parenchyma (HP). The contrast effects in the AO, PV, and HP were significantly delayed under medetomidine sedation compared to the control anesthesia protocol. Particularly, the contrast effect in the PV and HP was significantly delayed under sedation, appearing approximately 1 min after contrast medium injection. This delay likely reflects the peripheral vasoconstrictive effect of medetomidine. We noted a generally early high contrast enhancement of the CVC under medetomidine sedation, likely contributed by the induced bradycardia. Therefore, findings obtained on contrast enhancement CT under medetomidine sedation may be different from those obtained under propofol-induced sevoflurane maintenance anesthesia. These differences are important to consider when using the findings to inform diagnosis.

Cardiac arrest identified by a chest CT scan in a patient with normal telemetry findings

Early recognition of cardiac arrest has been linked traditionally to clinical signs and telemetry findings. Few case reports have presented normal telemetry findings in patients with cardiac arrest where a contrast enhanced CT scan of the chest was able to identify the diagnosis. The early recognition of a cardiac arrest whether by telemetry monitoring or CT scan is important to improve the clinical outcomes. This case report presents a patient who was hypertensive and unresponsive upon arrival to the emergency department. A chest CT scan to rule out aortic dissection showed no contrast in the pulmonary arteries, aorta, and the rest of the heart chambers although normal telemetry findings were present. Resuscitation was initiated, and patient survived with poor neurological recovery.