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Persistent dyspnea in post-covid patients in the absence of pulmonary embolism: added value of lung perfusion scintigraphy
Clinical and Translational Imaging ; 10(SUPPL 1):S13-S14, 2022.
Article in English | EMBASE | ID: covidwho-1894692
ABSTRACT
Background-

Aim:

While there's a wide literature on CT abnormalities in COVID-19 sequelae, the role of lung perfusion scintigraphy have been scarcely investigated. Recent findings reported lung microvascular and endothelial alterations in patients recovered from COVID-19 without pulmonary embolism, presenting persistent dyspnea (POST-COVID). We compared perfusion scintigraphy and CT findings of these patients with dyspneic subjects in whom lung scintigraphy excluded pulmonary embolism (NON-COVID). In POST-COVID patients, the correlation between lung perfusion scintigraphic findings and (1) CT abnormalities, and (2) clinical/ biochemical parameters were also assessed.

Methods:

24 POST-COVID and 33 NON-COVID patients who underwent lung perfusion scintigraphy for dyspnea from March 2020 to December 2021 were retrospectively enrolled. High-resolution chest CT performed 15 days before/after lung perfusion scintigraphy were available in 15/24 POST-COVID and 15/33 NON-COVID patients. From scintigraphic images counting rates for upper, middle, and lower fields were calculated in order to compute their ratio with total lung counts (UTR, MTR, and LTR, respectively) for both right and left lungs (RL and LL, respectively). CT images were analyzed using a semi-automated segmentation algorithm of 3D Slicer ( http//www.slicer.org), obtaining total, infiltrated and blood vessels' volumes, in order to calculate the infiltration rate (IR) and vascular density (VD). White blood cells, platelets, PT, INR, PTT, fibrinogen, and D-dimer of 15/24 POST-COVID patients were also collected from blood tests performed before the lung perfusion scintigraphy.

Results:

POST-COVID patients with persistent dyspnea showed reduced LTR (RL 22.4% ± 6.6%;LL 24.7% ± 3.1%) and higher MTR (RL 55.2% ± 5.2%;LL 49.1% ± 3.3%) compared to non- COVID patients (RL-LTR 29.6% ± 6.0%, p<0.0001;LL-LTR 28.3% ± 4.6%, p = 0.001;RL-MTR 47.3% ± 4.2%, p<0.0001;LL-MTR 47.3% ± 3.0%, p = 0.036), while UTR resulted bilaterally superimposable between the two groups. Similar IR and VD values at CT imaging were documented bilaterally in both groups. In POSTCOVID patients, no significant correlations between lung perfusion scintigraphy and CT findings were observed. Correlation analysis indicated D-dimer levels as associated with UTR (Pearson's r = 0.664;p = 0.007) and MTR (Pearson's r = - 0.555;p = 0.032), while no parameter significantly associated with LTR was observed.

Conclusions:

Lung perfusion scintigraphy can reveal reduced perfusion rates of lower pulmonary fields in POST-COVID patients with persistent dyspnea in the absence of pulmonary embolism, independently from CT abnormalities, infection duration and coagulation biomarkers. Although mechanisms underlying these findings need to be supported by pathological lung tissue examination, lung nonthrombotic microvascular and endothelial dysfunction may be involved.
Keywords

Full text: Available Collection: Databases of international organizations Database: EMBASE Topics: Long Covid Language: English Journal: Clinical and Translational Imaging Year: 2022 Document Type: Article

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Full text: Available Collection: Databases of international organizations Database: EMBASE Topics: Long Covid Language: English Journal: Clinical and Translational Imaging Year: 2022 Document Type: Article