Contrast layering artefact mimicking aortic dissection in a patient on veno-arterial extracorporeal membrane oxygenation undergoing computed tomography scan

Veno-arterial extracorporeal membrane oxygenation for post-infarction ventricular septal defect in a low-volume center

Managing patients with post-ischaemic ventricular septal defects (VSD) and postcardiotomy cardiogenic shock can be extremely challenging in a low-volume cardiac surgery unit. We present a case of a 68-year-old patient who received veno-arterial extracorporeal membrane oxygenation support due to cardiogenic shock after VSD repair. The patient was successfully weaned off support after 86 h. In the postoperative period, mediastinitis occurred, and negative pressure wound therapy was instituted.

Performing chest computed tomography on pediatric patients on extracorporeal membrane oxygenation (ECMO): a stepwise approach

Chest CT in pediatric patients on extracorporeal membrane oxygenation (ECMO) can be done safely and provide valuable high-quality diagnostic images to help guide patient management. An understanding of the basics of the ECMO circuit, cannula locations, where and how to inject contrast media, and how to time image acquisition is vital for the radiologist. Additionally, understanding the precautions associated with performing these exams is essential to ensure the safety of the child. This article provides a brief review of pediatric ECMO and its challenges and considerations, as well as a stepwise approach to perform and optimize these exams safely.

The Dean Effect: An Aortic Arch Flow Artifact Mimicking Dissection

The unique hemodynamics of the aortic arch create conditions for potential formation of a flow-related artifact that mimics disease on CT angiographic images. The hemodynamic basis for this artifact can be explained by fluid mechanics incorporating a mathematical principle known as the Dean number. Therefore, in this review, the artifact is referred to as the Dean effect. It is important for radiologists and other clinicians to recognize this artifact when encountered. It is also helpful for the interpreting radiologist to have a basic understanding of the relevant hemodynamic principles. This review provides an example of the artifact, reviews the basic underlying hemodynamics, and presents methods of how to prevent this artifact and distinguish it from pathologic mimics in clinical practice. Keywords: CT Angiography, Vascular, Thorax, Aorta, Artifacts, Blood, Dissection, Hemodynamics/Flow Dynamics © RSNA, 2022.

Optimizing Contrast-Enhanced Thoracoabdominal CT in Patients During Extracorporeal Membrane Oxygenation

RATIONALE AND OBJECTIVES

To evaluate the quality and value of contrast-enhanced (CE) chest- and abdominal computed tomography (CT) and CT angiography in neonates, children, and adults undergoing extracorporeal membrane oxygenation (ECMO) using a customized protocol for contrast delivery.

MATERIALS AND METHODS

All patients admitted for CE thoracic- and/or abdominal CT while on ECMO were prospectively included in the study. A protocol for contrast delivery adapted for the type of ECMO circulation, cannulation sites, anatomy of interest, and desired contrast phase was applied. Clinical information, ECMO and CT technique, including contrast administration strategy, was noted for each patient. Two radiologists separately evaluated the quality of the scan. The value of the examination was decided in consensus with the referring ECMO physician.

RESULTS

One hundred thirty CE thoracoabdominal scans were performed at 103 different occasions during the study time. Eighty-nine scans were performed during veno-arterial ECMO and 41 during veno-venous ECMO. In the majority, contrast was delivered to the oxygenator with preserved ECMO flow. A peripheral or central venous line with reduced flow was utilized in the remaining cases. Mean scan quality was graded 4.2 on a five-grade scale. In 56% of the examinations, the findings affected the immediate treatment of the patient.

CONCLUSION

High-quality CT and CT angiography can be achieved in ECMO patients of different ages and clinical issues considering the type of ECMO circulation, ECMO cannulation sites, preferred contrast phase and anatomy of interest. CT diagnoses affect the treatment of the patient.

Mechanical Circulatory Support for Acute Heart Failure Complicated by Cardiogenic Shock

Acute heart failure is a potentially life-threatening condition that can lead to cardiogenic shock, which is associated with hypotension and organ failure. Although there have been many studies on the treatment for cardiogenic shock, early mortality remains high at 40–50%. No new medicines for cardiogenic shock have been developed. Recently, there has been a gradual decline in the use of the intra-aortic balloon pump mainly due to a lack of adequate hemodynamic support. Extracorporeal membrane oxygenation and the percutaneous ventricular assist device have become more widely used in recent years. A thorough understanding of the mechanisms of such mechanical support devices and their hemodynamic effects, components of the devices, implantation technique, management, criteria for indications or contraindications of use, and clinical outcomes as well as multidisciplinary decision making may improve the outcomes in patients experiencing cardiogenic shock.

Clinical Pearls of Venoarterial Extracorporeal Membrane Oxygenation for Cardiogenic Shock

Extracorporeal membrane oxygenation (ECMO) is a technique that uses a pump to drain blood from a body, circulate blood through a membrane lung, and return the oxygenated blood back into the body. Venoarterial (VA) ECMO is a simplified version of the heart-lung machine that assists native pulmonary and/or cardiac function. VA ECMO is composed of a drainage cannula in the venous system and a return cannula in the arterial system. Because VA ECMO can increase tissue perfusion by increasing the arterial blood flow, it is used to treat medically refractory cardiogenic shock or cardiac arrest. VA ECMO has a distinct physiology that is referred to as differential flows. It can cause several complications such as left ventricular distension with pulmonary edema, distal limb ischemia, bleeding, and thromboembolism. Physicians who are using this technology should be knowledgeable on the prevention and management of these complications. We review the basic physiology of VA ECMO, the mechanism of complications, and the simple management of VA ECMO.