Time-related aortic inflammatory response, as assessed with 18F-FDG PET/CT, in patients hospitalized with severely or critical COVID-19: the COVAIR study

Effects of Chemotherapy on Aortic 18-Fluorodeoxyglucose Uptake in Patients With Hodgkin and Non-Hodgkin Lymphoma

Background

Despite advances in the treatment of oncology patients, therapy-related side effects may lead to premature morbidity. Inflammatory activation that has been linked to cardiovascular disease is crucial for the pathogenesis of both Hodgkin (HL) and non-Hodgkin lymphoma (NHL).

Objectives

The purpose of this study was to assess the vascular effects of chemotherapy in patients with HL and NHL by positron emission tomography/computed tomography with 18-fluorodeoxyglucose (18-FDG PET/CT) and to investigate interactions with systemic inflammation as assessed by circulating inflammatory markers.

Methods

Between July 2015 and July 2019, 65 consecutive patients (mean age 56 ± 17.78 years) with confirmed diagnosis of either HL (n = 33) or NHL (n = 32) were prospectively studied. PET/CT imaging was performed at baseline, at an interim phase, and after first-line treatment. Aortic FDG uptake was assessed by measuring global aortic target-to-background ratio (GLA-TBR). Serum biomarkers interleukin (IL)-6 and IL-1b were measured at each phase.

Results

Patients with HL demonstrated significant reduction in aortic TBR after first-line treatment (median GLA-TBR baseline: 1.98, median GLA-TBR third scan: 1.75, median difference = -0.20, 95% CI: -0.07 to -0.33, P = 0.006), which remained significant after adjustment for confounders (adj. R2 of model = 0.53). In contrast, patients with NHL did not demonstrate a significant aortic inflammation response (P = 0.306). Furthermore, patients with HL demonstrated a significant reduction in IL-6 (P = 0.048) and IL-1b (P = 0.045), whereas patients with NHL did not demonstrate significant reduction in IL-6 (P = 0.085) and IL-1b levels (P = 0.476).

Conclusions

Aortic inflammation, as assessed by 18-FDG PET/CT, is reduced in HL patients after first-line treatment but not in NHL patients. These findings imply that different pathophysiological pathways and different therapies might affect the arterial bed in different ways for patients with lymphoma.

Orthostatic Intolerance after COVID-19 Infection: Is Disturbed Microcirculation of the Vasa Vasorum of Capacitance Vessels the Primary Defect?

Following COVID-19 infection, a substantial proportion of patients suffer from persistent symptoms known as Long COVID. Among the main symptoms are fatigue, cognitive dysfunction, muscle weakness and orthostatic intolerance (OI). These symptoms also occur in myalgic encephalomyelitis/chronic fatigue (ME/CFS). OI is highly prevalent in ME/CFS and develops early during or after acute COVID-19 infection. The causes for OI are unknown and autonomic dysfunction is hypothetically assumed to be the primary cause, presumably as a consequence of neuroinflammation. Here, we propose an alternative, primary vascular mechanism as the underlying cause of OI in Long COVID. We assume that the capacitance vessel system, which plays a key role in physiologic orthostatic regulation, becomes dysfunctional due to a disturbance of the microvessels and the vasa vasorum, which supply large parts of the wall of those large vessels. We assume that the known microcirculatory disturbance found after COVID-19 infection, resulting from endothelial dysfunction, microthrombus formation and rheological disturbances of blood cells (altered deformability), also affects the vasa vasorum to impair the function of the capacitance vessels. In an attempt to compensate for the vascular deficit, sympathetic activity overshoots to further worsen OI, resulting in a vicious circle that maintains OI. The resulting orthostatic stress, in turn, plays a key role in autonomic dysfunction and the pathophysiology of ME/CFS.

Oncology and cardiology positron emission tomography/computed tomography faced with COVID-19: A review of available literature data

The COVID-19 pandemic has forced people to significantly change their lifestyles and attitudes, and has greatly burdened healthcare delivery systems worldwide. The redistribution of the medical delivery system to maintain normal medical care while responding generously to COVID-19 is a continuing challenge that weighs heavily on medical institutions. Among imaging modalities, chest X-rays and computed tomography (CT) examinations have clearly made a large contribution to treatment of COVID-19. In contrast, it is difficult to express the standpoint of nuclear medicine examinations in a straightforward manner, as the greatest emphasis in this modality has been on how necessary medical care can continue to be provided. Many clinical reports of nuclear medicine examinations related to COVID-19 have been published, and knowledge continues to accumulate. This review provides a summary of the current state of oncology and cardiology positron emission tomography (PET) examinations related to COVID-19, and includes preparation of the nuclear medicine department, trends in PET examinations, specific imaging findings on 18F-fluorodeoxyglucose (FDG) PET/CT, imaging of complications of COVID-19, PET tracers other than FDG, and the effects of vaccines on PET imaging findings.