Longitudinal lung function assessment of patients hospitalised with COVID-19 using 1H and 129Xe lung MRI

Introduction: The progression of pathophysiological pulmonary changes in patients following acute COVID-19 is not well established. Method(s): Patients hospitalised with COVID-19 pneumonia without signs of ILD, had MRI exams at a median of 6 (n=9), 12 (n=9), 25 (n=7), and 52 (n=3) weeks. MRI sequences included: dynamic contrast enhanced (DCE) lung perfusion,129 Xe diffusion weighted (DW-MRI), 129Xe ventilation and 129Xe 3D dissolved phase imaging. Result(s): 9 patients (age 56+/-9 years;7 male;1 required treatment in an ICU) were recruited. Median RBC:TP was abnormally low at all visits compared to reference age and sex matched data. An individual's RBC:TP was significantly and positively associated with an increase in their pulmonary blood volume (p=0.026). For patients with 52 week data available, one showed a continued increase in RBC:TP, 2 patients maintained a low RBC:TP (Figure 1). Ventilation defect percentage, and ventilation heterogeneity significantly decreased at 25 weeks compared to 6 129 129 129 weeks (p=0.010 and p=0.048). DW-MRI was normal at all visits. Dissolved phase xenon imaging showed RBC:TP significantly increased at 12 and 25 weeks compared to 6 weeks (p=0.048). Conclusion(s): In patients recovering after COVID-19, poor gas transfer is reflected by impaired xenon transfer, which improves alongside pulmonary blood volume.

Longitudinal 129xe and 1h Lung Mri Assessment of Lung Structure, Ventilation, Perfusion, and Gas Transfer Following Hospitalization with Covid-19

The long-term effects of coronavirus disease 2019 (COVID- 19) pneumonia on the lungs and pulmonary circulation require further characterization. We assessed progression of pathophysiological pulmonary changes during 1 year of follow-up of patients who had been hospitalized because of COVID-19. After discharge, recruited patients had up to four MRI examinations at a median of 6 (n=9), 12 (n=9), 25 (n=7) and 52 (n=3) weeks. Lung MRI examinations included: ultra-short echo time (UTE), dynamic contrastenhanced (DCE) lung perfusion, 129Xe diffusion weighted (DW-MRI), 129Xe ventilation and 129Xe 3D dissolved phase imaging. Nine patients (age 56 +/-9 years;six male) were recruited. Ventilation defect percentage and whole lung coefficient of variation of lung ventilation decreased significantly at 25 weeks (visit 3) compared with visit 1 at 6 weeks (p=0.010 and p=0.048). The UTE imaging indicated no evidence of lung scarring, and DW-MRI indicated normal lung microstructure across all visits. Dissolved phase xenon imaging showed that RBC:TP increased significantly at visits 2 and 3 compared with visit 1 (p=0.048). Median RBC:TP was abnormally low at all visits compared with reference age- and sex-matched data. An individual's RBC:TP was associated significantly and positively with an increase in their pulmonary blood volume (p=0.026). For patients with 52-week data available, one showed a continued improvement in RBC:TP;however, two of the patients maintained a low RBC:TP. In patients recovering from COVID-19, xenon gas transfer improves alongside pulmonary blood volume. Further work is needed to establish the proportion of post-COVID-19 patients who have longer-term impairment in xenon transfer and to correlate changes in lung MRI parameters with symptoms, lung function tests and other imaging modalities. Persistent impairment of xenon transfer might represent a physiological mechanism underlying ongoing symptoms in some patients and might indicate damage to the pulmonary microcirculation.

COVID-19 DISRUPTION TO PROSTATE CANCER MANAGEMENT IN A UK TERTIARY REFERRAL CENTRE

INTRODUCTION AND OBJECTIVE: Covid-19 caused major disruptions to cancer diagnosis and treatment. We aimed to evaluate the longitudinal disruption to prostate cancer management. METHODS: We completed a prospective service evaluation from 01/09/2019 to 31/08/2021 of all referrals, investigations, and treatments for prostate cancer at a single centre. The first UK Covid-19 lockdown occurred from 23/03/20 to 04/07/2020: monthly data for the time period before, during, and after the first UK lockdown were compared using ANOVA and Tukey HSD. RESULTS: We identified 4501 patients for inclusion. There was a profound decrease in all aspects of prostate cancer management during the first lockdown period. For pre-lockdown, lockdown, and postlockdown periods respectively, the mean monthly rates were: 256 v 125 v 363 PSA tests (p=0.0003);86 v 40 v 79 two-week-wait referrals (p=0.0005);62 v 18 v 54 MRI imaging for possible cancer (p<0.0001);32 v 15 v 36 diagnoses (p=0.002);17 v 9 v 14 prostatectomies (p=0.06). In the period after the first lockdown, despite the previous drop, we did not observe an increase in the number of referrals, MRI imaging, diagnoses, or treatment required (including active monitoring, chemotherapy, radiotherapy, prostatectomy, and palliative care) in comparison to pre-lockdown levels (all p>0.05). However, interestingly, we did see an increase in the number of PSA tests performed (p=0.04), which continued through the two subsequent UK lockdowns. CONCLUSIONS: To our knowledge, this is the first study to provide an overview of the impact of COVID-19 national lockdowns on the whole prostate cancer management pathway - from initial referral to final treatment. Despite the disruption to prostate cancer management during the first UK Covid-19 lockdown leading to a decrease in referrals, diagnoses and treatment in the context of reduced PSA testing, we have not seen a subsequent increase in these numbers after lockdown despite a rise in PSA testing. The rise in the number PSA tests performed post-lockdown may suggest a degree of compensatory PSA observation in the community. (Figure Presented).

Parenchymal involvement on CT pulmonary angiography in SARS-CoV-2 Alpha variant infection and correlation of COVID-19 CT severity score with clinical disease severity and short-term prognosis in a UK cohort.

AIM: To determine if there is a difference in radiological, biochemical, or clinical severity between patients infected with Alpha-variant SARS-CoV-2 compared with those infected with pre-existing strains, and to determine if the computed tomography (CT) severity score (CTSS) for COVID-19 pneumonitis correlates with clinical severity and can prognosticate outcomes. MATERIALS AND METHODS: Blinded CTSS scoring was applied to 137 hospital patients who had undergone both CT pulmonary angiography (CTPA) and whole-genome sequencing of SARS-CoV-2 within 14 days of CTPA between 1/12/20-5/1/21. RESULTS: There was no evidence of a difference in imaging severity on CTPA, viral load, clinical parameters of severity, or outcomes between Alpha and preceding variants. CTSS on CTPA strongly correlates with clinical and biochemical severity at the time of CTPA, and with patient outcomes. Classifying CTSS into a binary value of "high" and "low", with a cut-off score of 14, patients with a high score have a significantly increased risk of deterioration, as defined by subsequent admission to critical care or death (multivariate hazard ratio [HR] 2.76, p<0.001), and hospital length of stay (17.4 versus 7.9 days, p<0.0001). CONCLUSION: There was no evidence of a difference in radiological severity of Alpha variant infection compared with pre-existing strains. High CTSS applied to CTPA is associated with increased risk of COVID-19 severity and poorer clinical outcomes and may be of use particularly in settings where CT is not performed for diagnosis of COVID-19 but rather is used following clinical deterioration.

COVID-19 pneumonia imaging follow-up: when and how? A proposition from ESTI and ESR.

This document from the European Society of Thoracic Imaging (ESTI) and the European Society of Radiology (ESR) discusses the role of imaging in the long-term follow-up of COVID-19 patients, to define which patients may benefit from imaging, and what imaging modalities and protocols should be used. Insights into imaging features encountered on computed tomography (CT) scans and potential pitfalls are discussed and possible areas for future review and research are also included. KEY POINTS: • Post-COVID-19 pneumonia changes are mainly consistent with prior organizing pneumonia and are likely to disappear within 12 months of recovery from the acute infection in the majority of patients. • At present, with the longest series of follow-up examinations reported not exceeding 12 months, the development of persistent or progressive fibrosis in at least some individuals cannot yet be excluded. • Residual ground glass opacification may be associated with persisting bronchial dilatation and distortion, and might be termed "fibrotic-like changes" probably consistent with prior organizing pneumonia.

Chest CT screening for COVID-19 in elective and emergency surgical patients: experience from a UK tertiary centre.

AIM: To determine the incidence of possible COVID-19-related lung changes on preoperative screening computed tomography (CT) for COVID-19 and how their findings influenced decision-making. To also to determine whether the patients were managed as COVID-19 patients after their imaging findings, and the proportion who had SARS-CoV2 reverse transcriptionpolymerase chain reaction (RT-PCR) testing. MATERIALS AND METHODS: A retrospective study was undertaken of consecutive patients having imaging prior to urgent elective surgery (n=156) or acute abdominal imaging (n=283). Lung findings were categorised according to the British Society of Thoracic Imaging (BSTI) guidelines. RT-PCR testing, management, and outcomes were determined from the electronic patient records. RESULTS: 3% (13/439) of CT examinations demonstrated findings of classic/probable COVID-19 pneumonia, whilst 4% (19/439) had findings indeterminate for COVID-19. Of the total cohort, 1.6% (7/439) subsequently had confirmed RT-PCR-positive COVID-19. Importantly, all the patients with a normal chest or alternative diagnoses on CT who had PCR testing within the next 7 days, had a negative RT-PCR (92/407). There was a change in surgical outcome in 6% (10/156) of the elective surgical cohort with no change to surgical management was demonstrated in the acute abdominal emergency cohort requiring surgery (2/283). CONCLUSION: There was a 7% (32/439) incidence of potential COVID-19-related lung changes in patients having preoperative CT. Although this altered surgical management in the elective surgical cohort, no change to surgical management was demonstrated in the acute abdominal emergency cohort requiring surgery.