Functional Alterations Due to COVID-19 Lung Lesions-Lessons From a Multicenter V/Q Scan-Based Registry.

PURPOSE: In coronavirus disease 2019 (COVID-19) patients, clinical manifestations as well as chest CT lesions are variable. Lung scintigraphy allows to assess and compare the regional distribution of ventilation and perfusion throughout the lungs. Our main objective was to describe ventilation and perfusion injury by type of chest CT lesions of COVID-19 infection using V/Q SPECT/CT imaging. PATIENTS AND METHODS: We explored a national registry including V/Q SPECT/CT performed during a proven acute SARS-CoV-2 infection. Chest CT findings of COVID-19 disease were classified in 3 elementary lesions: ground-glass opacities, crazy-paving (CP), and consolidation. For each type of chest CT lesions, a semiquantitative evaluation of ventilation and perfusion was visually performed using a 5-point scale score (0 = normal to 4 = absent function). RESULTS: V/Q SPECT/CT was performed in 145 patients recruited in 9 nuclear medicine departments. Parenchymal lesions were visible in 126 patients (86.9%). Ground-glass opacities were visible in 33 patients (22.8%) and were responsible for minimal perfusion impairment (perfusion score [mean ± SD], 0.9 ± 0.6) and moderate ventilation impairment (ventilation score, 1.7 ± 1); CP was visible in 43 patients (29.7%) and caused moderate perfusion impairment (2.1 ± 1.1) and moderate-to-severe ventilation impairment (2.5 ± 1.1); consolidation was visible in 89 patients (61.4%) and was associated with moderate perfusion impairment (2.1 ± 1) and severe ventilation impairment (3.0 ± 0.9). CONCLUSIONS: In COVID-19 patients assessed with V/Q SPECT/CT, a large proportion demonstrated parenchymal lung lesions on CT, responsible for ventilation and perfusion injury. COVID-19-related pulmonary lesions were, in order of frequency and functional impairment, consolidations, CP, and ground-glass opacity, with typically a reverse mismatched or matched pattern.

Lung Scintigraphy for Pulmonary Embolism Diagnosis in COVID-19 Patients: A Multicenter Study.

In patients with novel coronavirus disease 2019 (COVID-19) referred for lung scintigraphy because of suspected pulmonary embolism (PE), there has been an ongoing debate within the nuclear medicine community as to whether and when the ventilation imaging should be performed. Indeed, whereas PE diagnosis typically relies on the recognition of ventilation-perfusion (V/P) mismatched defects, the ventilation procedure potentially increases the risk of contamination to health-care workers. The primary aim of this study was to assess the role of ventilation imaging when lung scintigraphy is performed because of suspected PE in COVID-19 patients. The secondary aim was to describe practices and imaging findings in this specific population. Methods: A national registry was created in collaboration with the French Society of Nuclear Medicine to collect lung scans performed on COVID-19 patients for suspected PE. The practices of departments were assessed regarding imaging protocols and aerosol precautions. A retrospective review of V/P SPECT/CT scans was then conducted. Two physicians masked to clinical information reviewed each case by sequentially viewing perfusion SPECT, perfusion SPECT/CT, and V/P SPECT/CT images. The scans were classified into 1 of the 4 following categories: patients for whom PE could reasonably be excluded on the basis of perfusion SPECT only, perfusion SPECT/CT, or V/P SPECT/CT and patients with mismatched defects suggestive of PE according to the European Association of Nuclear Medicine criteria. Results: Data from 12 French nuclear medicine departments were collected. Lung scans were performed between March 2020 and April 2021. Personal protective equipment and dedicated cleaning procedures were used in all departments. Of the 145 V/Q SPECT/CT scans included in the central review, PE could be excluded using only perfusion SPECT, perfusion SPECT/CT, or V/P SPECT/CT in 27 (19%), 55 (38%), and 45 (31%) patients, respectively. V/P SPECT/CT was positive for PE in 18 (12%) patients, including 12 (67%) with a low burden of PE (≤10%). Conclusion: In this population of COVID-19 patients assessed with lung scintigraphy, PE could confidently be excluded without the ventilation imaging in only 57% of patients. Ventilation imaging was required to confidently rule out PE in 31% of patients. Overall, the prevalence of PE was low (12%).

CT abnormalities evocative of lung infection are associated with lower 18F-FDG uptake in confirmed COVID-19 patients.

PURPOSE: CT signs that are evocative of lung COVID-19 infections have been extensively described, whereas 18F-FDG-PET signs have not. Our current study aimed to identify specific COVID-19 18F-FDG-PET signs in patients that were (i) suspected to have a lung infection based on 18F-FDG-PET/CT recorded during the COVID-19 outbreak and (ii) whose COVID-19 diagnosis was definitely established or excluded by appropriate viral testing. METHODS: Twenty-two consecutive patients referred for routine 18F-FDG-PET/CT examinations during the COVID-19 outbreak (March 25th to May 15th 2020) and for whom CT slices were evocative of a lung infection were included in the study. All patients had undergone a SARS-COV-2 diagnostic test to confirm COVID-19 infection (positivity was based on molecular and/or serological tests) or exclude it (negativity of at least the serological test). RESULTS: Eleven patients were confirmed to be affected by COVID-19 (COVID+), whereas the other eleven patients were not (COVID-) and were predominantly suspected of having bacterial pneumonia. CT abnormalities were not significantly different between COVID+ and COVID- groups, although trends toward larger CT abnormalities (p = 0.16) and lower rates of consolidation patterns (0.09) were observed in the COVID+ group. The maximal standardized uptake values (SUVmax) of lung areas with CT abnormalities were however significantly lower in the COVID+ than the COVID- group (3.7 ± 1.9 vs. 6.9 ± 4.1, p = 0.03), with the highest SUVmax consistently not associated with COVID-19. CONCLUSION: Among CT abnormalities evocative of lung infection, those related to COVID-19 are associated with a more limited 18F-FDG uptake. This observation may help improve our ability to detect COVID-19 patients.

Signs of tracheobronchitis may constitute the principal finding on the lung SPECT/CT images of COVID-19 patients.

BACKGROUND: This study aimed to analyze the rates of tracheobronchitis signs observed on the ventilation scans of COVID-19 patients with shortness of breath, with comparisons to a non-COVID population. METHODS: Lung scintigraphy was collected in 10 such COVID patients, as well as from a non-COVID population investigated outside the epidemic wave period, on a CZT-SPECT/CT system, with ventilation images recorded with 99mTc-labeled Technegas® and perfusion images with 99mTc-labeled albumin macroaggregates. RESULTS: A diffuse tracheobronchial uptake was observed on the ventilation scans from 3 COVID patients (30%), whereas this rate was 3% (3/90) in the non-COVID group (P = 0.013). These 3 patients had no laryngeal extension of Technegas® uptake and limited parenchymal lung abnormalities. Follow-up scintigraphy demonstrated the withdrawal of tracheobronchitis signs in two cases, and the advent of a severe pulmonary embolism in one. CONCLUSION: Signs of tracheobronchitis may constitute the principal finding on lung SPECT/CT images of COVID-19 patients with shortness of breath.