Long-term lung perfusion changes related to COVID-19: a dual energy computed tomography study

Abstract

Purpose: Although the findings of acute new coronavirus disease (COVID-19) infection on dual-energy computed tomography (DECT) have recently been defined, the long-term changes in lung perfusion associated with COVID-19 pneumonia have not yet been clarified. We aimed to examine the longterm course of lung perfusion in COVID-19 pneumonia cases using DECT and to compare changes in lung perfusion to clinical and laboratory findings.

Methods: On initial and follow-up DECT scans, the presence and extent of perfusion deficit (PD) and parenchymal changes were assessed. The associations between PD presence and laboratory parameters, initial DECT severity score, and symptoms were evaluated.

Results: The study population included 18 females and 26 males with an average age of 61.32 ± 11.3 years. Follow-up DECT examinations were performed after the mean of 83.12 ± 7.1 (80-94 days) days. PDs were detected on the follow-up DECT scans of 16 (36.3%) patients. These 16 patients also had ground-glass parenchymal lesions on the follow-up DECT scans. Patients with persistent lung PDs had significantly higher mean initial D-dimer, fibrinogen, and C-reactive protein values than patients without PDs. Patients with persistent PDs also had significantly higher rates of persistent symptoms.

Conclusion: Ground-glass opacities and lung PDs associated with COVID-19 pneumonia can persist for up to 80-90 days. Dual-energy computed tomography can be used to reveal long-term parenchymal and perfusion changes. Persistent PDs are commonly seen together with persistent COVID-19 symptoms.

Keywords: COVID-19; DECT; follow-up; lung; perfusion deficit.

Figure 1

Thirty-two-year-old male. Initial dual-energy computed tomography image. Consolidations (arrows) are present.

Figure 2

The same patient as in Figure 1. Initial dual-energy computed tomography images. Consolidation-related perfusion deficits are observed (arrows).

Figure 3, 4

Follow-up (after 87 days) dual-energy computed tomography (DECT) images of the same patient as in Figures 1 and 2. Follow-up DECT scan reveals no parenchymal (Figure 3) or perfusion (Figure 4) abnormality.

Figure 5

Fifty-year-old male. Initial dual-energy computed tomography images. Ground-glass opacities (arrows) are marked.

Figure 6

The same patient as in Figure 5. Initial dual-energy computed tomography images. Consolidation-related perfusion deficits are marked.

Figure 7, 8

Follow-up (after 81 days) dual-energy computed tomography images of the same patient as in Figures 5 and 6. The regressed parenchymal opacities (Figure 7) and their corresponding regressed perfusion deficit (Figure 8) are indicated.

Figure 9

Receiver-operating-characteristic curve of the D-dimer, C-reactive protein, computed tomography severity index, and fibrinogen levels to predict future perfusion deficits. AUC; area under the curve; CT; computed tomography; CRP, C-reactive protein.