Change in cancer diagnosis during the COVID-19 pandemic: Trends estimated from FDG-PET/CT.

The aim of this study is to clarify changes in the circumstances of cancer diagnoses during the COVID-19 pandemic in Tokyo, Japan, estimated from [18F]-2-fluoro-2-deoxy-D-glucose (FDG) -positron emission tomography/ computed tomography (PET/CT) for cancer patients. Cancer diagnosis in pandemic status (PANS) was evaluated by retrospective review of the findings of FDG-PET/CT examinations performed between 11 March 2020 and 28 December 2021 for initial staging and restaging for malignancy. Evaluation of cancer diagnosis in pre-pandemic status (pPANS) was conducted similarly in FDG-PET/CT examinations performed between 4 January 2018 and 10 March 2020. Of these, patients with malignant lymphoma (ML), lung cancer, esophageal cancer, and colorectal cancer who had a pathologically proven diagnosis or clinical diagnosis following therapy of the disease were selected for analysis. Initial cancer staging was determined by the diagnostic report of FDG-PET/CT. Change in cancer stage and in the number of FDG-PET/CT examinations performed was evaluated between pPANS and PANS, and according to term of the pandemic and vaccination status. The COVID-19 epidemic influenced the number of cancer patients who underwent FDG-PET/CT. There was a marked decrease in the number of cancer patients receiving FDG-PET/CT in Terms 1-3 (March 2020 to February 2021), but it recovered in Terms 4-6 (March 2021 to December 2021). There was no significant difference between PANS and pPANS in terms of the initial stage of cancer, but Stage IV ML and Stage II esophageal cancer were more frequent in PANS. Initial staging of ML, lung cancer, and esophageal cancer revealed more advanced cancer stages in Terms 4-6 compared with Terms 1-3. The number of patients receiving FDG-PET/CT in Tokyo was influenced by the COVID-19 epidemic. Staging based on FDG-PET/CT shifted to more advanced cancer stage during the pandemic compared with pre-pandemic.

Fatty liver on computed tomography scan on admission is a risk factor for severe coronavirus disease.

OBJECTIVES: To alleviate the overflow of coronavirus disease 2019 (COVID-19) patients in hospitals, less invasive and simple criteria are required to triage the patients. We evaluated the relationship between COVID-19 severity and fatty liver on plain computed tomography (CT) scan performed on admission. METHODS: In this retrospective cohort study, we considered all COVID-19 patients at a large tertiary care hospital between January 31 and August 31, 2020. COVID-19 severity was categorized into severe (moderate and severe) and non-severe (asymptomatic and mild) groups, based on the Japanese National COVID-19 guidelines. Fatty liver was detected on plain CT scan. Multivariate logistic regression analysis was performed to evaluate factors associated with severe COVID-19. RESULTS: Of 222 patients (median age: 52 years), 3.2%, 58.1%, 20.7%, and 18.0% presented with asymptomatic, mild, moderate, and severe COVID-19, respectively. Although 59.9% had no fatty liver on plain CT, mild, moderate, and severe fatty liver occurred in 13.1%, 18.9%, and 8.1%, respectively. Age and presence of fatty liver were significantly associated with severe COVID-19. CONCLUSION: Our study showed that fatty liver on plain CT scan on admission can become a risk factor for severe COVID-19. This finding may help clinicians to easily triage COVID-19 patients.

Clinical and radiological findings of silent hypoxia among COVID-19 patients.

The aim of this study was to describe the clinical and radiological findings of COVID-19 patients with "silent hypoxia," who had no dyspnea on admission even though their oximetry saturation was less than 94%. This retrospective cohort study included all COVID-19 patients (n = 270) at a large tertiary care hospital between January 31 and August 31, 2020. Clinical and radiological characteristics of patients who met our criteria of "silent hypoxia", which included those who reported no dyspnea even though oximetry saturation was <94%, were extracted. Eight patients (3.0%) met the criteria for "silent hypoxia." The median age was 61 years (interquartile range [IQR]: 48.8-72.3), and five (62.5%) were men. All patients had consolidation on CT and showed a moderate to high COVID-19 CT severity score (median: 13.5, IQR: 10.8-15.3). The median FIO2 of the maximum oxygen required was 55 (IQR: 28-70)%. Two patients (25.0%) were intubated, and one patient (12.5%) underwent extracorporeal membrane oxygenation. Some COVID-19 patients with "silent hypoxia" may develop severe disease. Close and accurate monitoring of patients using arterial blood gas and pulse oximetry is necessary, regardless of their symptoms.

FDG-PET/CT images of COVID-19: a comprehensive review.

Following a lot of reports of coronavirus disease 2019 (COVID-19) CT images, the feature of FDG-PET/ CT imaging of COVID-19 was reported in several articles. Since FDG accumulates in activated inflammatory cells, FDG-PET/CT has huge potential for diagnosing and monitoring of inflammatory disease. However, FDG-PET/CT cannot be routinely used in an emergency setting and is not generally recommended as a first choice for diagnosis of infectious diseases. In this review, we demonstrate FDG-PET/CT imaging features of COVID-19, including our experience and current knowledge, and discuss the value of FDG-PET/CT in terms of estimating the pathologic mechanism.