Ventilation perfusion lung SPECT/CT in pregnancy during COVID-19

Assessment of pulmonary embolism related to active SARS-CoV-2 infection in pregnant women

AIM

To analyze a sample of pregnant patients who underwent pulmonary perfusion scintigraphy to rule out suspicion of pulmonary embolism (PE) during the acute COVID-19 infection hospitalization period in our hospital.

MATERIAL AND METHODS

SPECT scintigraphy with a reduced dose (111MBq) of 99mTc-macroaggregated albumin was performed in all the patients (n=5). The images obtained were interpreted by comparing the findings with the radiological images according to the PISAPED criteria.

RESULTS

Only one of the 5 patients was diagnosed with PE. Two patients showed pathological scintigraphy findings attributable to radiological alterations due to COVID-19 pneumonia, and the other two had normal pulmonary perfusion.

CONCLUSION

Given the non-specific features of the clinical manifestations and d-dimer values ​​in COVID-19, as well as their similarity to those of PE, pulmonary perfusion scintigraphy plays a crucial role in the screening of PE in these patients due to its high sensitivity and lower irradiation compared to CT. Despite the limited number of patients, the results obtained have special relevance due to the absence of scientific publications in this group of patients within the exceptional context of the COVID-19 pandemic.

COVID-19: Findings in nuclear medicine from head to toe

COVID-19 is a multisystemic disease, and hence its potential manifestations on nuclear medicine imaging can extend beyond the lung. Therefore, it is important for the nuclear medicine physician to recognize these manifestations in the clinic. While FDG-PET/CT is not indicated routinely in COVID-19 evaluation, its unique capability to provide a functional and anatomical assessment of the entire body means that it can be a powerful tool to monitor acute, subacute, and long-term effects of COVID-19. Single-photon scintigraphy is routinely used to assess conditions such as pulmonary embolism, cardiac ischemia, and thyroiditis, and COVID-19 may present in these studies. The most common nuclear imaging finding of COVID-19 vaccination to date is hypermetabolic axillary lymphadenopathy. This may pose important diagnostic and management dilemmas in oncologic patients, particularly those with malignancies where the axilla constitutes a lymphatic drainage area. This article aims to summarize the relevant literature published since the beginning of the pandemic on the intersection between COVID-19 and nuclear medicine.

[Assessment of pulmonary embolism related to active SARS-CoV-2 infection in pregnant women.]

AIM

To analyze the sample of pregnant patients who underwent pulmonary perfusion scintigraphy to rule out the pulmonary embolism (PE) suspicion during the acute COVID-19 infection hospitalization period in our hospital.

MATERIAL AND METHODS

SPECT scintigraphy with a reduced dose (111 MBq) of 99mTc-macroaggregated albumin was performed in all of the patients (n=5). The obtained images were interpreted by comparing the findings with the radiological images according to the PISAPED criteria.

RESULTS

Only one of the 5 patients was diagnosed with PE. Two patients obtained pathological findings of the scintigraphy attributable to radiological alterations due to COVID-19 pneumonia, and the other two had normal pulmonary perfussion.

CONCLUSION

Given the non-specific features of the clinical manifestations and D-dimer values in COVID-19, as well as their similarity to those of PE, the pulmonary perfusion scintigraphy plays a crucial role in the screening of PE in these patients due to its high sensitivity and lower irradiation compared to CT. Despite the limited number of patients, the results obtained have special relevance related to the absence of scientific publications on this group of patients within the context of COVID-19 pandemic exceptional situation.

Imaging Pulmonary Blood Vessels and Ventilation-Perfusion Mismatch in COVID-19

COVID-19 hypoxemic patients although sharing a same etiology (SARS-CoV-2 infection) present themselves quite differently from one another. Patients also respond differently to prescribed medicine and to prone Vs supine bed positions. A severe pulmonary ventilation-perfusion mismatch usually triggers moderate to severe COVID-19 cases. Imaging can aid the physician in assessing severity of COVID-19. Although useful for their portability X-ray and ultrasound serving on the frontline to evaluate lung parenchymal abnormalities are unable to provide information about pulmonary vasculature and blood flow redistribution which is a consequence of hypoxemia in COVID-19. Advanced imaging modalities such as computed tomography, single-photon emission tomography, and electrical impedance tomography use a sharp algorithm visualizing pulmonary ventilation-perfusion mismatch in the abnormal and in the apparently normal parenchyma. Imaging helps to access the severity of infection, lung performance, ventilation-perfusion mismatch, and informs strategies for medical treatment. This review summarizes the capacity of these imaging modalities to assess ventilation-perfusion mismatch in COVID-19. Despite having limitations, these modalities provide vital information on blood volume distribution, pulmonary embolism, pulmonary vasculature and are useful to assess severity of lung disease and effectiveness of treatment in COVID-19 patients.