Subcostal Views

Subcostal long-axis view

Subcostal short-axis view

The subcostal view is essential in newborns. Due to the echogenecity of the liver, it offers a great view for a sweep to evaluate for function, pericardial effusion and anatomy. Because newborns are sensitive from the abdomen, one may go very gently to acquire images in this view. It is also a great view for line positioning (bicaval view) and for the position of the umbilical arterial line. One may also appreciate presence of pleural effusion in that view, by sliding towards the lung fields. The first view here evaluates the situs, with the aorta to the left of the IVC. One should sweep to ensure that the IVC connects, as expected, to the right atrium.

Cross-section through the liver at sub-xyphoid area to ouline the situs. The Aorta is posterior to the SVC and is to the left of the SVC. The SVC is to the right of the aorta and anterior. The sweep should go to the right atrium and confirm the connection between the "IVC" presumed vessel and the right atrium.

This is a sweep in the subcostal view from posterior to anterior in the long-axis. One may appreciate nicely the performance of both the LV and the RV. We can also appreciate the respective outflow tracts.

RVOT view from the subcostal area. Nice view to evaluate inflow and outflow of the right ventricle from the subcostal region.

Simultaneous evaluation of the atrial septum in the long axis view of the subcostal acquisition. Important to evaluate for presence of an inter-atrial shunt.

In this view, one may observe a small restrictive muscular VSD. The sweep outlines the anatomy and interrogates the inter-ventricular septum throughout its length.

One may appreciate the SVC connecting to the right atrium, as well as a inter-atrial septal defect between the RA and the left atrium.

Measurement of the SVC at its right atrial connection. One may also use this view to locate the tip of a central line.

Sweep with colour in the subcostal long-axis view. One may see the sweep from the atrial level towards the RVOT, by sweeping anteriorly. We may notice a small PFO that is left to right. The SVC is seen draining to the right atrium. We also can evaluate the LVOT and flow through it. A portion of the ventricular septum may be see within the colour box.

Left to right Patent foramen ovale (PFO)

Bidirectional PFO

Right to left PFO

Bidirectional PFO

Left to right PFO

Right to left PFO

Left to right component to an inter-atrial shunt

Right to left component to an inter-atrial shunt

Another example of the short axis - atrial view

Example of atrial view in the long-axis cut of the subcostal view. Here, we may appreciate the B-Mode and the simultaneous colour. Notice that the frame per second is very low at 28 Hz (fps), which is secondary to the double panel. The PFO can be observed (red), and is left to right. We may also notice some pulmonary veins entering the left atrium, and the SVC entering the right atrium.

Another example of the long axis - atrial bicaval view

Example of the atrial view in the short-axis cut of the subcostal view (bicaval view). Here we may notice the PFO that is left to right (red "flame"), the SVC and the IVC entering the right atrium. This is a good view to evaluate the SVC velocities, which may be increased in the context of a Vein of Galen malformation. It is also a good view to visualize venous access and for their position at the SVC-RA or IVC-RA junction. It is also a good view to visualize the ECMO V-V cannula.

Subcostal short-axis view. In 2D, one may appreciate the sweep. Visualisation of the IVC connecting to the RA (with the eustachian valve), as well as the SVC connecting to the RA. This view is ideal to visualize the RVOT (especially if a suspicion of pulmonary stenosis). It is also ideal to interrogate the flow in the descending Aorta. This view allows to evaluate for the insertion of the tricuspid valve apparatus.

PW of the SVC flow, as well as VTI of the SVC flow.

This is the view to rule out sinus venosus defect, as well as interrogate SVC flow. A sinus venosus defect is seen when a right pulmonary vein unroofs in the SVC.

Short Axis view outlining the SVC flow entering the right atrium.

Short-axis of the subcostal acquisition with visualisation of the RVOT and eventually providing you with sweep. One may sometimes appreciate septal configuration if the parasternal short axis view is obstructed.

Another example of the bicaval view - one of the views that may be usable to measure the SVC diameter.

SVC flow may be visualized with the colour box.

PW-Doppler of the SVC at its insertion in the right atrium. The VTI is 0.143 and can be used to estimate SVC flow (of interest in Vein of Galen malformation).

Subcostal view with descending aortic flow. One may recognize the aorta as the large vessel along the spine.

Retrograde flow in the descending aorta from ductal steal.

2D-colour over the descending aorta

PW of the descending aorta with retrograde flow (holodiastolic).

Presence of holodiastolic retrograde flow. In this particular example, there was NO PDA. However, we can see that in HIE with cerebral vascular loss of autoregulation and steal within the brain vasculature during diastole.

Holodiastolic retrograde flow in the post-ductal aorta:

Patent ductus arteriosus with aorto to pulmonary shunt in diastole (diastolic steal; "left to right" in diastole); PVR < SVR
- Aorto-pulmonary window in diastolic steal. Similar mechanism than the PDA.
- BTT Shunt. Similar mechanism than the PDA
- Pott shunt. Usually placed for severe pulmonary arterial hypertension and unlikely to cause steal effect due to the PVR >>> SVR. However, there are rare situations where there is a combination of pulmonary vasodilators and resting status that may lead to occasional steal in diastole if PVR are momentarily infra-systemic.
Major aortopulmonary collaterals (MAPCAs).
Common Arterial Trunk ("Truncus Arteriosus") with diastolic steal
Any congenital heart defect with a patent PDA (either naturally or induced by prostaglandins) and retrograde flow in diastole due to steal into the pulmonary vasculature. Ex: HLHS, Tricuspid Atresia, PAIVS, dTGA, etc.
Aorto-Ventricular Tunnel (leads to a diastolic steal in the entire aortic arch, including ascending aorta). This includes tunnel to the left or the right ventricle.
Significant Aortic Insufficiency/Regurgitation (leads to a diastolic steal in the entire aortic arch, including the ascending aorta). This includes ruptured sinus of Vasalva aneurysm.
Cerebro-vascular dilatation (low of cerebral vascular resistance with relative higher systemic vascular resistance in other organs, can lead to retrograde flow in diastole; seen in situations like neonatal hypoxic ischemic encephalopathy during the hyperluscency stage; status epilepticus exposed to anti-seizure medications)
Coronary-cameral fistula. Coronary artery–to–venous or pulmonary artery fistulae. Coronary to sinusoids (RV-dependent coronary circulation) if the RV end-diastolic pressure falls (ex: post RVOT obstacle removal).
Cerebral arteriovenous malformation (such as in Vein of Galen malformation).
Large non-cerebral AV malformations (e.g., hepatic, cutaneous in syndromic contexts) can similarly create a systemic diastolic steal pattern typically in the aortic area distal from the feeding vessel.
Iatrogenic causes (e.g., ECMO circuit steal): Not directly a cardiac shunt, but VA-ECMO cannulation with altered systemic runoff can occasionally show diastolic retrograde aortic flow, especially if left ventricular ejection is minimal.
Pulmonary Arteriovenous Malformations (PAVMs): Rare in neonates but possible in hereditary syndromes or post-Glenn physiology. Leads to left-to-right steal at the capillary level — could produce retrograde aortic flow if significant enough.

Of note, ascending aorta retrograde flow in systole may be seen in situations where there is:

Hypoplastic Left Heart Syndrome (HLHS): The ascending aorta is perfused retrogradely via the ductus arteriosus, as the left heart cannot generate forward flow.
Severe left ventricular (LV) dysfunction with minimal or absent systolic output: In extreme cases, LV systolic function is insufficient to produce antegrade flow, resulting in retrograde ductal perfusion of the ascending aorta (a physiology similar to HLHS).
Critical aortic stenosis (subvalvar, valvar, or supravalvar): Severe outflow tract obstruction can result in minimal systolic flow into the ascending aorta, with retrograde perfusion from the duct or collaterals.
LV inflow or diastolic filling impairment (non-systolic heart failure): Conditions such as hypertrophic cardiomyopathy, restrictive cardiomyopathy, or severe hypovolemia/preload reduction may impair LV filling to the point of markedly reduced stroke volume and low forward flow.

Subcostal view showing the descending aorta with red flow (coming towards the probe) indicating forward flow with the umbilical arterial line in the descending aorta.

Subcostal view of the descending aorta with colour flow. An umbilical arterial catheter is observed with the tip at the level of the diaphragm. The flow in the celiac artery is seen.

Various degree of holo-diastolic retrograde flow in the descending abdominal aorta

2D and Colour visualizing the celiac and superior mesenteric artery branching from the descending aorta from the subcostal view. One may also appreciate an umbilical arterial line in the descending aorta.

Bicaval view with VV-ECMO cannula in the SVC

Umbilical arterial line in the descending aorta, arriving at the diaphragmatic junction.

Umbilical venous line in the IVC entering the RA.

Colour over the IVC and sub-hepatic veins. Cursor is being placed in the sub-hepatic veins in anticipation of the PW-Doppler.

PW-Doppler in the sub-hepatic veins. Here we can appreciate that there is significantly component that is retrograde. This may indicate higher RA pressure than expected: RV hypertrophy, mechanical ventilation, RV failure leading to high RA pressure, obstructive lesions of the right heart.

IVC enters the RA and is of good caliber, but is collapsible indicating that the RA pressure is unlikely to be high. Volume status is likely to be adequate as it does not collapse fully (however, caveat is that this may be difficult to apply in infants on positive respiratory pressure as this may lead to less IVC collapsibility).