COVID-19 Stroke Apical Lung Examination Study: A Diagnostic and Prognostic Imaging Biomarker in Suspected Acute Stroke

Abstract

Background and purpose: Diagnosis of coronavirus disease 2019 (COVID-19) relies on clinical features and reverse-transcriptase polymerase chain reaction testing, but the sensitivity is limited. Carotid CTA is a routine acute stroke investigation and includes the lung apices. We evaluated CTA as a potential COVID-19 diagnostic imaging biomarker.

Materials and methods: This was a multicenter, retrospective study (n = 225) including CTAs of patients with suspected acute stroke from 3 hyperacute stroke units (March-April 2020). We evaluated the reliability and accuracy of candidate diagnostic imaging biomarkers. Demographics, clinical features, and risk factors for COVID-19 and stroke were analyzed using univariate and multivariate statistics.

Results: Apical ground-glass opacification was present in 22.2% (50/225) of patients. Ground-glass opacification had high interrater reliability (Fleiss κ = 0.81; 95% CI, 0.68-0.95) and, compared with reverse-transcriptase polymerase chain reaction, had good diagnostic performance (sensitivity, 75% [95% CI, 56-87]; specificity, 81% [95% CI, 71-88]; OR = 11.65 [95% CI, 4.14-32.78]; P < .001) on multivariate analysis. In contrast, all other contemporaneous demographic, clinical, and imaging features available at CTA were not diagnostic for COVID-19. The presence of apical ground-glass opacification was an independent predictor of increased 30-day mortality (18.0% versus 5.7%, P = .017; hazard ratio = 3.51; 95% CI, 1.42-8.66; P = .006).

Conclusions: We identified a simple, reliable, and accurate COVID-19 diagnostic and prognostic imaging biomarker obtained from CTA lung apices: the presence or absence of ground-glass opacification. Our findings have important implications in the management of patients presenting with suspected stroke through early identification of COVID-19 and the subsequent limitation of disease transmission.

FIG 1.

A, There are multiple, bilateral, focal, peripheral-predominant areas of ground-glass opacification, commonly seen in patients with COVID-19 pulmonary infection. B, There are multiple, focal 5- to 6-mm nodules with surrounding ground-glass change in the left upper lobe. This is an indeterminate COVID-19 appearance and would be more suggestive of atypical or fungal infection. C, There is bilateral ground-glass opacification posteriorly, more on the right, consistent with dependent change. This is a characteristic appearance, not associated with COVID-19, and classically disappears in the prone position. There is also a general hazy appearance not seen in A and B, which does not represent abnormal lung and is artifactual due to movement.

FIG 2.

Kaplan-Meier analysis. Association between GGO and mortality was evaluated using Kaplan-Meier survival analysis; 82.0% of patients in the group with GGO were alive at 30 days compared with 94.3% in the group without GGO (P = .005).