Table 5.

Factors to consider in the application of non-invasive imaging in COVID-19.

Factor	Considerations	Comment
Who to scan?	Biomarkers (troponin, D-dimer, ferritin, potentially BNP); ECG changes; cardiac symptoms; known cardiac disease	Biomarker cut-offs are unclear—the general trend and overall picture are likely to be the deciding factor until further data guide further ECG changes can be non-specific, and the entire clinical picture must be taken into consideration
	Critically and seriously unwell patients (abnormal haemodynamics and oxygen requirements)	Echo is likely to be the most available imaging modality in the critically unwell
	Prognostication and triage decisions for escalation to critical care level 2 care where resources are limited	This is a topic of medical ethics. Imaging may guide requirements for higher care and may inform probability of survival, although on a population rather than individual level. Echo can provide sufficient data
How to scan?	Echo, CMR, and CT are all considerations from the cardiovascular perspective	See Table 1 for advantages vs. disadvantages of echo vs. CMR. See Table 4 for potential uses of cardiac CT. CMR is likely best reserved for those with ongoing symptoms after recovery from acute COVID or in those with abnormal echocardiography
	Diagnostic considerations	Echo may be indicated to guide diagnosis of hypotension and differentiate septic shock vs. cardiogenic shock (thus guide inotropic, mechanical support decisions, maybe even transplant decisions). Cardiac CT offers a potential “quadruple rule-out” for assessment of aortic, pulmonary, coronary and myocardial pathology. See text for other considerations
When to scan?	Acute Outpatient—early vs. mid vs. long term Monitoring progress	These are factors that will require further exploration. Echo clearly permits accessible, convenient and serial follow-up whether as an inpatient or outpatient CMR may be a good pre-discharge assessment of cardiac status and, if abnormal, might be repeated as an outpatient to track longitudinal change. Where this is not practicable, an early outpatient CMR may be performed. Progress may be monitored by serial echo, especially in those who are severely ill and those with abnormalities on a baseline echo, with response to treatments including proning, steroids, oxygen, and novel therapies
Resource availability	Scanning systems (echo, CMR or CT); scanner time and availability; sonographer/radiographer expertise and availability; reporting clinician availability	Availability of all these factors will vary between units and countries. At a pragmatic level, these factors must be balanced against the considerations above to create locally achievable processes, while constraints are tackled to permit wider access
Safety considerations	Infection prevention	Strict considerations to mitigate risks of infection transmission during echo, CMR and CT studies are essential. Appropriate PPE and timing of the study are critical here, to balance the infection risk vs. potential improvements in clinical outcomes afforded by the data revealed by the study in question TTE should be the echo modality of choice rather than TOE—and TOE reserved for very highly selective cases due to its aerosol-generating nature—to cases where the TOE finding will change management. This is likely to be a very small proportion of cases, such as ICU cases where TTE windows are non-diagnostic
	Study duration? Role for abbreviated echo studies	Focused echo (level 1 echo or modified level 1 echo) will certainly provide useful data; tailoring what to truncate is a fine art and better applied by more senior practitioners than junior staff
Treatment	A role for imaging guided changes in treatment is not yet defined.	Potentially, imaging findings of right ventricular dysfunction, dilatation or pulmonary hypertension might trigger earlier initiation of advanced therapies ads they become identified

COVID-19, coronavirus disease 2019; BNP, brain natriuretic peptide; CMR, cardiac magnetic resonance; PPE, personal protective equipment; TTE, transthoracic echocardiography; TOE, transoesophageal echocardiography; ICU, intensive care unit.