Vivek Yedavalli
The COVID-19 pandemic has undeniably impacted all walks of life by putting a significant strain on health care resources. The number of ways in which the pandemic has changed health care is an ongoing topic of interest within the research community. Neuroradiology is arguably one of the most dramatically affected subspecialties in all of health care with significant changes in neuroimaging utilization, especially with respect to stroke imaging. In this edition of the AJNR News Digest, we showcase several recent articles investigating the impact of COVID-19 on stroke diagnosis and stroke neuroimaging utilization.
Acute ischemic stroke (AIS) is one of the leading causes of morbidity and mortality in the US and the world.1 The mean global lifetime risk of stroke in men and women ages 25 and older is 25%.2 In 2015 alone, stroke health care costs amounted to $46 billion in total resources for diagnosis and long-term management.3 Appropriate stroke treatment and management are highly dependent on timely and accurate neuroimaging evaluation. For instance, a number of trials in 2015 and onward have shown the benefits of neuroimaging in triaging stroke patients for endovascular thrombectomy (EVT) in patients with AIS secondary to large-vessel occlusion (LVO) with the time window for treatment now extended to 16–24 hours.4,5
COVID-19 has had a disproportionate impact on stroke evaluation with neuroimaging in particular. Several studies have now shown that COVID-19 increases the risk of stroke6,7 in all ages,8 with an overall incidence ranging from 1.4%9 to 4.9%.6 Early neuroimaging with CT and MRI also plays an integral role in assessing the severity of disease burden.7 However, the pandemic has had varying effects on stroke imaging utilization throughout its course. During the earlier stages, mitigation measures led to substantial decreases in stroke imaging utilization, which subsequently recovered once reopenings occurred.10,11 In addition to stroke imaging utilization, the overall impact on overall stroke detection continues to be exhaustively explored during this dynamic process.
Recent reports have shown varied results in stroke detection—and overall stroke imaging utilization—are dependent on the phase of the pandemic. For instance, utilizing natural language processing methods of over 32,000 CT and MRI radiology reports, Li et al demonstrated a 24% decrease in acute and subacute stroke detection by neuroimaging during March to April 2020 when compared with the 2017–2019 prepandemic time frame.12 Other studies have also corroborated these findings of decreased stroke and penumbra detection due to both decreased utilization10,13 along with decreased hospitalizations overall14,15 during the early phase of the pandemic. More recently, Kansagra et al showed that while reopenings increased stroke imaging detection and overall utilization, the overall rates were still slightly lower than the prepandemic period.10 The true impact on detection and utilization still remains to be seen in the coming years.
COVID-19 vaccinations have also played a crucial role in significantly mitigating the spread of disease and decreasing the overall severity in the unlikely event of infection.16 Recent studies have shown that AIS can still be a complication in vaccinated individuals. AIS can occur either as a complication of postvaccination COVID-19 infection or from the vaccine itself, though both instances are exceedingly rare. Notably, postvaccination AIS is still more commonly associated with infection than the vaccination.17 The type of vaccine also plays a role in the risk of postvaccination AIS and other stroke subtypes.17 In these rare instances of postvaccination AIS, there is still a void in how best to utilize neuroimaging in differentiating each etiology. Therefore, the effects of widespread vaccination on stroke detection and utilization are still an ongoing area of research.
The chosen articles provide a strong overview on how the pandemic has affected stroke imaging and its overall utilization thus far. In summary, the pandemic has led to decreased stroke detection and neuroimaging utilization during the early phase of the pandemic, with gradual recovery now approaching prepandemic levels. As the pandemic is ongoing, its overall impact on stroke imaging and health care remains to be seen in the coming years. Please refer to these papers for exhaustive reports on the pandemic’s continued impact on stroke imaging.