Soundeffects news | Erika Cavanagh, FASA (AUS)

Erika Cavanagh, FASA (AUS)

Mater Centre for Maternal Fetal Medicine OBSTETRICS

Meet Erika Cavanagh, a senior sonographer and expert in obstetric ultrasound at the Mater Centre for Maternal Fetal Medicine in Brisbane, Queensland. With 20 years of experience and a focus on tertiary level obstetrics, Erika specialises in areas such as placental dysfunction, fetal echocardiography, and multiple pregnancy assessment. Currently pursuing a PhD on the correlation between placental imaging and function in fetal growth restriction, Erika’s dedication to advancing the field is clear. Her commitment extends to sonographer education, where she actively contributes by presenting on various topics at ASA conferences and serving as a sessional lecturer at the Queensland University of Technology. We asked Erika about the topics she will be presenting at this year’s ASA conference and how important collaboration is in our profession.

Do you think placenta accreta spectrum incidence is increasing or are we improving detection rates as our knowledge of the physiological change improves and we become more aware of key US findings? Is there one diagnostic sign that is the most accurate in detecting PAS?

The incidence of PAS is certainly increasing with an increase in caesarean section rates; however, we are improving our detection of ultrasound signs of the condition. Ultrasound has been proven as a very sensitive diagnostic tool in suspected PAS, but we need to remember that PAS is a diagnosis that can only be made at delivery. Some placentas that look as though they may likely be adherent come away easily at delivery. With ultrasound, we can only see signs of PAS. The one ultrasound sign that I think is the key to PAS is a thickened, heterogeneous, low-lying placenta. It is a very characteristic appearance and should raise the sonographer’s suspicions about PAS instantly.

What are some of the common signs of congenital fetal infection, and what are the key takeaways from your lecture for sonographers?

A lot of different fetal infections have similar presentations on ultrasound. Probably the most obvious and serious sign is non-immune hydrops and/or a raised MCA peak systolic velocity, associated with fetal anaemia. Whenever a fetus has unexplained hydrops, congenital infections should be assumed until proven otherwise. Another ultrasound sign common to many congenital infections is a fetus that is small for gestational age. Within my department, we operate a fetal growth clinic where we work up pregnancies that are SGA or growth restricted. A significant proportion of these pregnancies are found to have congenital CMV, so it pays to think outside the box a little when you come across an SGA baby in your day-today practice.

Can you discuss the implications of an incorrect diagnosis of FGR/SGA?

SGA refers to a statistical deviation from the normal fetal growth – that is, EFW under the 10th percentile. By definition, 10% of fetuses will measure at or under the 10th percentile. SGA may be constitutional (meaning that the fetus is genetically preordained to measure in the smaller range) or it may be pathological, often caused by placental dysfunction. The trick is working out whether the fetus is meant to be small, or whether it is not reaching its growth potential because of uteroplacental circulatory issues. In addition, some fetuses that ARE pathologically growth restricted don’t actually measure under the 10th percentile.

It is very important to perform a good quality, accurate growth scan, looking at all the biometric and Doppler parameters so that we don’t overlook a fetus that is growth restricted.

Fetal growth restriction is one of the leading causes of fetal morbidity and mortality. These fetuses need to be closely monitored to optimise the timing of delivery because there is no treatment for fetal growth restriction, and the fetus is at a much higher risk of stillbirth.

What are the common misconceptions about fetal cardiac imaging?

The most common misconception about fetal cardiac imaging is that if the heart is normal at the morphology scan, then there is no need to look any further later in the pregnancy. Many cardiac anomalies are progressive, meaning that they may be subtle or even not present at the morphology scan, but they develop throughout the pregnancy. Some of these pathologies, such as coarctation of the aorta, aortic stenosis or pulmonary stenosis can be extremely serious for the newborn. Any advance notice of a severe cardiac anomaly before birth is beneficial for planning and counselling.

The other misconception is that the quality of cardiac assessment significantly decreases after 24 weeks’ gestation. The key to a good quality cardiac assessment in the third trimester is appropriate image optimisation, careful interrogation of imaging windows, and knowing what appearances are normal and abnormal. This last point is often the most difficult, and that is where practice and experience come in.

Can you share a positive experience where collaboration or networking played a crucial role in your professional journey?

In my time as a director on the ASA board, and my years as a volunteer for the ASA, I have been introduced to countless sonographers from all different parts of Australia and New Zealand, and all different professional backgrounds and levels of experience. This has provided invaluable networking possibilities. As a result, I have benefitted from the opportunity to work collaboratively with a diverse range of people in research, professional development, advocacy and guiding the profession. This has been invaluable in my occupational journey and has opened a lot of doors in my career.