Interview with Assema Lalzad, ASA Research Grant Co-Recipient 2020

ASA RESEARCH GRANTS

Assema Lalzad

ASA Research Grant Co-Recipient 2020

Research Project: Bioeffects of Doppler ultrasound on the newborn brain: A pilot study to investigate structural effects in an in vivo rat model. Host Organisation: Monash University

What is your research project about? What methods are you using?

Given that ultrasound carries thermal and mechanical energy, of which 99% is absorbed by the brain tissue, it is reasonable to speculate that the energy dissipated may trigger a reactive response in the exposed region. Such a response could theoretically invoke an inflammatory and injurious process. In this study, we focus on the inflammatory processes of the central nervous system (CNS), which is the hallmark of the brain’s initial reaction to any external stimuli, stress, injury or disease process. Based on the established association between acute injury and neuroinflammation through the activation of the immune cells of the CNS, we developed a study with the aim to investigate the bioeffects of B-mode ultrasound on the mammalian brain using an in vivo rat model to observe histological changes associated with potential neuroinflammation in the insonated brain region. Specifically, we aimed to explore activation of microglia and increased density of astrocyte. We hypothesise that clinical diagnostic levels of B-mode ultrasound (a 10-minute continuous exposure) can induce neuroinflammation in the exposed regions.

What is the current status of your research project?

This research has been completed and a manuscript has been prepared for publication and is awaiting approval.

Why did you want to undertake this research?

Despite the absence of ionising radiation, the potential for ultrasound to interact with biological tissue has been established, albeit in very limited studies. All of these studies relate to the use of Doppler mode ultrasound exposure, due to the fact that traditionally the highest ultrasound intensities have been associated with Doppler mode. No consideration has been given for B-mode exposure, despite the exponential rise in B-mode intensities relative to Doppler mode in the 20 years from 1990 to 2010. No research in the field of ultrasound bioeffects has explored the postnatal scan of the human neonatal brain. Therefore, we have no clinically relevant information on the possible biological effects that may occur when the preterm brain is exposed to ultrasound directly via the fontanelle.

What are you hoping to achieve with your research?

The clinical safety of cranial ultrasound was insinuated three decades ago as a result of the undisputed absence of ionising radiation and any associated obvious short- or long-term deleterious effects, as well as no empirical evidence of adverse outcomes arising from ultrasound exposure during pregnancy. Ultrasound is, however, not as risk free as once thought, conceding to the intensities associated with everevolving present-day technology. It is hoped that this research will draw attention to the often disregarded field of ultrasound biosafety.

What did you gain from doing the research?

This research provides breakthrough evidence on the presence of neuroinflammation in the mammalian brain after exposure to B-mode ultrasound via the transcranial window.

Would you undertake it again?

It is not known if the observed neuroinflammatory changes in response to ultrasound exposure are transient and carry risk for cognitive and/or functional deficits and if these changes observed in the rat are also occurring in the human preterm brain. This necessitates further research into the safety profile of neonatal cranial scans using larger observational longitudinal studies. It would be a privilege for me to be part of a research team that would conduct such a study in the future.

What (if any) challenges did you face, and how did you overcome them?

One of the aims of our study was to examine bioeffects of neonatal cranial ultrasound under clinically relevant conditions. Ideally, to simulate the neonatal cranial scan of the preterm human infant requires the use of a rodent model with a postnatal age of less than 10 days. Although this research used 9-week-old rats as study models, the small size of the brains proved very difficult to interrogate with ultrasound. However, the research was not concerned with pathological or structural changes visible with ultrasound. Therefore, the small size of the brains and reduced resolution did not impact the outcome of the research.

You were one of the recipients of the 2020 ASA Research Grant; why did you apply and how has the grant assisted in your research?

I had anticipated to utilise an NHMRC grant (awarded in 2016) on the proposed animal study which was the final phase of my PhD. However, with the impact of COVID-19, the university froze all research funds. This prevented the conduct of the animal study. The university suggested I change the direction of my PhD or limit the scope of the research originally planned. At this time, many other funding bodies were reluctant to provide research funding under the same circumstances, especially given the limited timelines. However, I remained fully committed to pursuing the completion of my original work. After a lengthy time spent sourcing scholarships and grant opportunities, I applied for and was awarded a research grant by the Australasian Sonographers Association to complete my original rat study. •

‘Ultrasound is, however, not as risk free as once thought, conceding to the intensities associated with ever-evolving present-day technology. It is hoped that this research will draw attention to the often disregarded field of ultrasound biosafety.’