Chest Computed Tomography Abnormalities and Their Relationship to the Clinical Manifestation of Respiratory Syncytial Virus Infection in a Genetically Confirmed Outbreak

Respiratory Syncytial Virus Infection: An Update

Respiratory syncytial virus (RSV) is a highly contagious respiratory virus that can cause mild to severe illness in children. It is the leading cause of lower respiratory tract infections (LRTI) in children under the age of one year, and it can also affect older children and adults, especially those with underlying medical conditions. In the post-COVID period, there seems to be an increase in the incidence, possibly due to 'immunity debt'. Symptoms of RSV infection in children may include fever, runny nose, and cough. In severe cases, it can lead to bronchiolitis (inflammation of the small airways in the lungs) or pneumonia (infection of the lungs). Most children with RSV infection recover within a week or two, but some may require hospitalization, especially those who are premature or have underlying medical conditions. As there is no specific treatment for RSV infection, supportive care is the mainstay of management. In severe cases, oxygen therapy or mechanical ventilation may be necessary. High flow nasal cannula seems to be beneficial. There have been promising advances in development of RSV vaccines; few trials in adults and pregnant women have reported encouraging results. The US FDA has approved two RSV vaccines for use in older adults (GSK's Arexvy and Pfizer's ABRYSVO).

Respiratory Syncytial Virus: A Systematic Review and Meta-Analysis of Tomographic Findings (2000-2022)

Human respiratory syncytial virus (RSV) is a main cause of medical referrals and hospitalizations in all infants, particularly among newborns. Nevertheless, relatively limited evidence on chest tomography (CT) findings has been collected. According to the PRISMA statement, Pubmed, Embase, and medRxiv were searched for eligible observational studies published up to 31 December 2022. Cases were categorized in children and adolescents (age < 18 years), adults and elderly (age ≥ 18 years), and immunocompromised patients, and then pooled in a random-effects model. Heterogeneity was assessed using the I2 statistics, while reporting bias was assessed by means of funnel plots and regression analysis. A total of 10 studies (217 RSV cases) were retrieved (children, 37.3%; immunocompromised, 41.0%; adults, 21.7%). The most common features were signs of organizing pneumonia (33.65%, 95% confidence interval [95% CI] 22.39-47.27), followed by septal thickening (33.19%, 95% CI 21.76-47.03), ground glass opacities (GGOs; 28.03%, 95% CI 14.69-46.82), and tree-in-bud (TIB, 27.44%, 95% CI 15.04-44.68). Interestingly, up to 16.23% (95% CI 8.17-29.69) showed normal findings, while the large majority (76.06%, 95% CI 64.81-84.56) were characterized by bilateral involvement. Studies were highly heterogeneous without substantial reporting bias. Assuming children and adolescents as reference groups, healthy adults were characterized by a higher risk ratio [RR] for septal thickening (RR 3.878, 95% CI 1.253-12.000), nodular lesions (RR 20.197, 95% CI 1.286-317.082), and GGOs (RR 2.121, 95% CI 1.121-4.013). RSV cases are rarely assessed in terms of CT characteristics. Our study identified some specificities, suggesting that RSV infections evolve heterogeneous CT features in children/adolescents and adults, but the paucity of studies recommends a cautious appraisal.

Centri-lobular pulmonary nodules on HRCT: incidence and approach for etiological diagnosis

Background

Centri-lobular nodules are the most common pattern of diffuse pulmonary nodules encountered on high-resolution computed tomography (HRCT). HRCT with post-processing techniques such as obtaining maximum intensity projection (MIP) is helpful in making centri-lobular nodules more conspicuous. The study aimed to highlight the role of HRCT with its reconstruction capabilities in the detection and characterization of centri-lobular pulmonary nodules, interpret the most frequent associated findings, and correlate with the clinical findings to reach the most appropriate diagnosis.

Results

The study included 58 patients; 41.4% males and 58.6% females. Their age ranged from 2 to 67 years with mean age of 25.69. The centri-lobular nodules numbers, distribution, shape, and associated HRCT chest findings were identified. The top three etiological diagnoses were infection/inflammation in 50.0% of cases followed by acute viral bronchiolitis in 27.6% and inhalation bronchiolitis in 19.0% of cases. Correlation of HRCT findings with the clinical diagnosis was carried out with consequent formulation of an algorithm for the diagnostic approach of various etiologies of centri-lobular pulmonary nodules.

Conclusions

HRCT is a useful tool in the detection and characterization of centri-lobular pulmonary nodules. It can be used to differentiate the different etiologies that share centri-lobular nodularity. Other associated features and multidisciplinary approach are essential for further characterization of the most relevant etiological diagnosis.

Meta-analysis of chest CT features of patients with COVID-19 pneumonia

The objective of this paper is to perform a meta‐analysis regarding the chest computed tomography (CT) manifestations of coronavirus disease‐2019 (COVID‐19) pneumonia patients. PubMed, Embase, and Cochrane Library databases were searched from 1 December 2019 to 1 May 2020 using the keywords of “COVID‐19 virus,” “the 2019 novel coronavirus,” “novel coronavirus,” and “COVID‐19.” Studies that evaluated the CT manifestations of common and severe COVID‐19 pneumonia were included. Among the 9736 searched results, 15 articles describing 1453 common patients and 697 severe patients met the inclusion criteria. Based on the CT images, the common patients were less frequent to exhibit consolidation (odds ratio [OR] = 0.31), pleural effusion (OR = 0.19), lymphadenopathy (OR = 0.17), crazy‐paving pattern (OR = 0.22), interlobular septal thickening (OR = 0.27), reticulation (OR = 0.20), traction bronchiectasis (OR = 0.40) with over two lobes involved (OR = 0.07) and central distribution (OR = 0.18) while more frequent to bear unilateral pneumonia (OR = 4.65) involving one lobe (OR = 13.84) or two lobes (OR = 6.95) when compared with severe patients. Other CT features including ground‐glass opacities (P = .404), air bronchogram (P = .070), nodule (P = .093), bronchial wall thickening (P = .15), subpleural band (P = .983), vascular enlargement (P = .207), and peripheral distribution (P = .668) did not have a significant association with the severity of the disease. No publication bias among the selected studies was suggested (Harbord's tests, P > .05 for all.) We obtained reliable estimates of the chest CT manifestations of COVID‐19 pneumonia patients, which might provide an important clue for the diagnosis and classification of COVID‐19 pneumonia.

We systematically assessed the chest CT manifestations in different severity of COVID‐19 pneumonia.

We analyzed the CT manifestations comprehensively and systematically from three aspects, including CT features, the number of lobes involved, as well as location and distribution of lesions.

The sample is large and the conclusions are convincing.