Chest Computed Tomography Patterns Research Articles

A Structured, Anatomy-Based Chest CT Interpretation Curriculum for Pulmonary Fellows Covering the Main Patterns of Parenchymal Lung Disease.

Chest computed tomography (CT) interpretation is a key competency for pulmonary fellows, with many resources intended for radiologists but very few for this specific group. We endeavored to create a curriculum to teach chest CT interpretation to first-year pulmonary fellows. We assembled a team of two pulmonologists, one radiologist, and a fellow with computer drafting software experience. We reviewed the literature, used principles of cognitive load theory to outline the content of our curriculum, collected original CT images exemplifying key patterns of disease, created original illustrations using computer drafting programs, and outlined frameworks to identify chest CT patterns and build differential diagnoses. We divided the material into five short videos and provided 18 practice cases to be reviewed asynchronously. We then organized a 1-hour in-person review session facilitated by a chest radiologist. We created a survey to assess our curriculum. The material presented here has been delivered to three consecutive classes of first-year pulmonary and critical care medicine fellows at our institution. Nineteen fellows in three cohorts reviewed the curriculum. Twelve fellows (63% response rate) completed the postcurriculum survey. Overall, there was a significant improvement in comfort, with the calculated paired sample t test showing a mean comfort of 3.2 precurriculum and a mean comfort of 4.5 postcurriculum (p < .001). This self-guided, interactive curriculum provides a structured approach connecting key lung anatomy to patterns of disease and is an effective way to teach chest CT interpretation to pulmonary fellows.

Quantitative analysis of chest CT in coronavirus infected patients and its correlation with clinical features

To explore the quantitative analysis results of different patterns of chest computed tomography (CT) in patients with coronavirus infection and its relationship with viral load and pathophysiological status. A retrospective clinical cohort study was conducted. Patients with coronavirus infection admitted to Qingdao Municipal Hospital from June 9 to 15, 2023 (all patients underwent chest CT examination within 24 hours after diagnosis) were enrolled. The patients were divided into coronavirus infection non-pneumonia group and coronavirus infection associated pneumonia group according to CT findings. Relevant baseline data, such as demographic characteristics, chest CT characteristics, and laboratory indicators within 12 hours before and after CT examination were collected from each group. Spearman correlation test was used to quantitatively analyze the correlation between CT features and laboratory indicators. The receiver operator characteristic curve (ROC curve) was drawn to evaluate the predictive value of each laboratory index for pneumonia in patients infected with coronavirus. Multiple linear regression analysis was used to explore the relationship between different CT patterns such as ground-glass opacity (GGO) and consolidation and ventilatory oxygenation status. A total of 171 patients were enrolled, including 44 patients in the coronavirus infection non-pneumonia group and 127 patients in the coronavirus infection associated pneumonia group (the incidence of pneumonia was 74.3%). Compared with patients with coronavirus infection alone, patients with coronavirus infection associated pneumonia had significantly lower lymphocyte count (LYM), oxygenation index (PaO2/FiO2), total lung capacity, GGO volume and GGO ratio, and significantly higher C-reactive protein (CRP), neutrophil/lymphocyte ratio (NLR), D-dimer, fraction of inspired oxygen (FiO2) level, real volume variation and consolidation ratio, the differences were all statistically significant. There were no statistically significant differences in the nucleocapin protein (N) gene cycle threshold (Ct) value and open reading frame (ORF) gene Ct value between the two groups. ROC curve analysis showed that, after adjusting for age, gender, CRP level and other related factors, compared with N gene Ct value, ORF gene Ct value, N gene Ct value+LYM, ORF gene Ct value+LYM, the LYM had the most potential diagnosis power for coronavirus infection associated pneumonia. The area under the ROC curve (AUC) of LYM for predicting coronavirus infection was 0.703. When the cut-off value of LYM was 0.7×109/L, the sensitivity was 55.5%, and the specificity was 79.5%, respectively. Multiple linear regression analysis showed that, when adjusted for consolidation ratio, age, gender, Hb and D-dimer levels, the GGO ratio in patients with coronavirus infection associated pneumonia was correlated with PaO2/FiO2 (β = -2.18, P < 0.001). When adjusted for GGO ratio, age, sex, Hb and D-dimer levels, the proportion of consolidation in patients with coronavirus infection associated pneumonia was correlated with PaCO2 (β = 0.36, P = 0.004). When adjusted for GGO ratio, the proportion of consolidation in patients with coronavirus infection associated pneumonia was also associated with NLR (β = 0.79, P = 0.006). LYM could be a potential marker for predicting coronavirus associated pneumonia, and the correlation seems to be independent of viral load. In addition, in the analysis of imaging features, GGO is associated with hypoxia, while consolidation is associated with PaCO2 level and inflammation. The increased proportion of consolidation in the whole lung may be detrimental to lung ventilation.

Laboratory data and broncho-alveolar lavage on Covid-19 patients with no intensive care unit admission: Correlation with chest CT features and clinical outcomes.

Broncho-alveolar lavage (BAL) is indicated in cases of uncertain diagnosis but high suspicion of Sars-Cov-2 infection allowing to collect material for microbiological culture to define the presence of coinfection or super-infection. This prospective study investigated the correlation between chest computed tomography (CT) findings, Covid-19 Reporting and Data System score, and clinical outcomes in Coronavirus disease 2019 (Covid-19) patients who underwent BAL with the aim of predicting outcomes such as lung coinfection, respiratory failure, and hospitalization length based on chest CT abnormalities. Study population included 34 patients (range 38-90 years old; 20 males, 14 females) with a positive nucleic acid amplification test for Covid-19 infection, suitable BAL examination, and good quality chest CT scan in the absence of lung cancer history. Pulmonary coinfections were found in 20.6% of patients, predominantly caused by bacteria. Specific correlations were found between right middle lobe involvement and pulmonary co-infections. Severe lung injury (PaO2/FiO2 ratio of 100-200) was associated with substantial involvement of right middle, right upper, and left lower lobes. No significant correlation was found between chest CT findings and inflammatory markers (C-reactive protein, procalcitonin) or hospitalization length of stay. Specific chest CT patterns, especially in right middle lobe, could serve as indicators for the presence of co-infections and disease severity in noncritically ill Covid-19 patients, aiding clinicians in timely interventions and personalized treatment strategies.

Real-Life Diagnostic Performance of the Hypersensitivity Pneumonitis Guidelines: A Multicenter Cohort Study.

Hypersensitivity pneumonitis (HP) is a heterogeneous interstitial lung disease (ILD) that may be difficult to confidently diagnose. Recently, the 2020 ATS/JRS/ALAT HP diagnostic guidelines were published, yet data validating their performance in real-life settings are scarce. We aimed to assess the diagnostic performance of the HP guidelines compared to the gold-standard multidisciplinary discussion (MDD). For this purpose, we included consecutive ILD patients that underwent diagnostic bronchoscopy between 2017 and 2020 in three large medical centers. Four diagnostic factors (antigen exposure history, chest computed tomography pattern, bronchoalveolar lavage lymphocyte count, and histology results) were used to assign guidelines-based HP diagnostic confidence levels for each patient. A sensitivity analysis was performed, with MDD diagnosis as the reference standard. Overall, 213 ILD patients were included, 45 (21%) with an MDD diagnosis of HP. The guidelines' moderate (≥70%) confidence threshold produced optimal performance with 73% sensitivity for HP, 89% specificity, and a J-index of 0.62. The area under the receiver operating characteristic curve (AUC) for a correct guidelines-based diagnosis was 0.86. The guidelines had better performance for non-fibrotic than fibrotic HP (AUC 0.92 vs. 0.82). All diagnostic factors, except bronchoalveolar lavage lymphocyte count, were independent predictors for MDD diagnosis of HP in a multivariate analysis. In conclusion, the HP guidelines exhibited a good diagnostic performance compared to MDD diagnosis in real-life setting.

Prevalence and outcomes of interstitial lung abnormalities in a Canadian lung cancer screening trial

RATIONALE Interstitial lung abnormalities (ILA) are radiographic interstitial findings that are incidentally identified on chest imaging performed for other reasons. ILAs have been identified on chest computed tomography (CT) performed as part of lung cancer screening programs. OBJECTIVES This study characterizes the prevalence and outcomes associated with ILA in a Canadian lung cancer screening cohort. METHODS Patients were identified from the Alberta lung cancer screening trial, a 5-year cohort study. CT reports were screened for terms associated with ILA including specific radiologic features and CT patterns. These were further characterized as non-subpleural, subpleural nonfibrotic and subpleural fibrotic, consistent with published definitions. Retrospective chart review was conducted for those with ILA to define demographics, lung function, and longitudinal outcomes including subsequent investigations for interstitial lung disease (ILD), treatment, and survival. MEASUREMENTS AND MAIN RESULTS Of 806 patients in the lung cancer screening study, 30 (3.7%) were identified as having ILA, with two-thirds (67%) having subpleural fibrotic abnormalities. Half of patients were referred to a Respirologist and underwent pulmonary function testing. Over a median follow-up period of two years, none were diagnosed with an idiopathic interstitial pneumonia, or started on immunomodulatory or antifibrotic therapy. Three of 30 (10%) patients demonstrated disease progression over time, all of whom had subpleural fibrotic ILA on baseline chest CT. CONCLUSIONS The prevalence of ILA in this Canadian lung cancer screening cohort was 3.7%. These data should inform the development of standardized reporting and follow-up for ILA as lung cancer screening programs are implemented.

The importance of chest CT severity score and lung CT patterns in risk assessment in COVID-19-associated pneumonia: a comparative study.

Chest computed tomography (CT) is suitable to assess morphological changes in the lungs. Chest CT scoring systems (CCTS) have been developed and use in order to quantify the severity of pulmonary involvement in COVID-19. CCTS has also been correlated with clinical outcomes. Here we wished to use a validated, relatively simple CTSS to assess chest CT patterns and to correlate CTSS with clinical outcomes in COVID-19. Altogether 227 COVID-19 cases underwent chest CT scanning using a 128 multi-detector CT scanner (SOMATOM Go Top, Siemens Healthineers, Germany). Specific pathological features, such as ground-glass opacity (GGO), crazy-paving pattern, consolidation, fibrosis, subpleural lines, pleural effusion, lymphadenopathy and pulmonary embolism were evaluated. CTSS developed by Pan et al. (CTSS-Pan) was applied. CTSS and specific pathologies were correlated with demographic, clinical and laboratory data, A-DROP scores, as well as outcome measures. We compared CTSS-Pan to two other CT scoring systems. The mean CTSS-Pan in the 227 COVID-19 patients was 14.6 ± 6.7. The need for ICU admission (p < 0.001) and death (p < 0.001) were significantly associated with higher CTSS. With respect to chest CT patterns, crazy-paving pattern was significantly associated with ICU admission. Subpleural lines exerted significant inverse associations with ICU admission and ventilation. Lymphadenopathy was associated with all three outcome parameters. Pulmonary embolism led to ICU admission. In the ROC analysis, CTSS>18.5 significantly predicted admission to ICU (p = 0.026) and CTSS>19.5 was the cutoff for increased mortality (p < 0.001). CTSS-Pan and the two other CTSS systems exerted similar performance. With respect to clinical outcomes, CTSS-Pan might have the best performance. CTSS may be suitable to assess severity and prognosis of COVID-19-associated pneumonia. CTSS and specific chest CT patterns may predict the need for ventilation, as well as mortality in COVID-19. This can help the physician to guide treatment strategies in COVID-19, as well as other pulmonary infections.

Isolated pulmonary langerhans cell histiocytosis: A diagnostic challenge in oncologic patients.

Isolated pulmonary langerhans cell histiocytosis: A diagnostic challenge in oncologic patients.

Chest computed tomography of suspected COVID-19 pneumonia in the Emergency Department: comparative analysis between patients with different vaccination status.

To identify differences in chest computed tomography (CT) of the symptomatic coronavirus disease 2019 (COVID-19) population according to the patients' severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination status (non-vaccinated, vaccinated with incomplete or complete vaccination cycle). CT examinations performed in the Emergency Department (ED) in May-November 2021 for suspected COVID-19 pneumonia with a positive SARS-CoV-2 test were retrospectively included. Personal data were compared for vaccination status. One 13-year experienced radiologist and two 4th-year radiology residents independently evaluated chest CT scans according to CO-RADS and ACR COVID classifications. In possible COVID-19 pneumonia cases, defined as CO-RADS 3 to 5 (ACR indeterminate and typical) by each reader, high involvement CT score (≥ 25%) and CT patterns (presence of ground glass opacities, consolidations, crazy paving areas) were compared for vaccination status. 184 patients with known vaccination status were included in the analysis: 111 non-vaccinated (60%) for SARS-CoV-2 infection, 21 (11%) with an incomplete vaccination cycle, and 52 (28%) with a complete vaccination cycle (6 different vaccine types). Multivariate logistic regression showed that the only factor predicting the absence of pneumonia (CO-RADS 1 and ACR negative cases) for the 3 readers was a complete vaccination cycle (OR = 12.8-13.1compared to non-vaccinated patients, p ≤ 0.032). Neither CT score nor CT patterns of possible COVID-19 pneumonia showed any statistically significant correlation with vaccination status for the 3 readers. Symptomatic SARS-CoV-2-infected patients with a complete vaccination cycle had much higher odds of showing a negative CT chest examination in ED compared to non-vaccinated patients. Neither CT involvement nor CT patterns of interstitial pneumonia showed differences across different vaccination status.

Long-term outcomes of COVID-19 convalescents: An 18.5-month longitudinal study in Wuhan

ObjectivesThis study aimed to describe the full scope of long-term outcomes and the ongoing pathophysiological alterations among COVID-19 survivors. MethodsWe established a longitudinal cohort of 208 COVID-19 convalescents and followed them at 3.3 (interquartile range [IQR]: 1.3, 4.4, visit 1), 9.2 (IQR: 9.0, 9.6, visit 2), and 18.5 (IQR: 18.2, 19.1, visit 3) months after infection, respectively. Serial changes in multiple physical and psychological outcomes were comprehensively characterized. We, in addition, explored the potential risk factors of SARS-CoV-2 antibody response and sequelae symptoms. ResultsWe observed continuous improvement of sequelae symptoms, lung function, chest computed tomography (CT), 6-minute walk test, and the Borg dyspnea scale, whereas sequelae symptoms (at least one) and abnormal chest CT patterns still existed in 45.2% and about 30% of participants at 18.5 months, respectively. Anxiety and depression disorders were alleviated for the convalescents, although depression status was sustained for a longer duration. ConclusionsMost COVID-19 convalescents had an overall improved physical and psychological health status, whereas sequelae symptoms, residual lesions on lung function, exercise impairment, and mental health disorders were still observed in a small proportion of participants at 18.5 months after infection. Implementing appropriate preventive and management strategies for the ever-growing COVID-19 population is warranted.

1103P Drug-related pneumonitis induced by osimertinib as first-line treatment for EGFR-positive non-small cell lung cancer: A real-world setting

Osimertinib has demonstrated impressive efficacy as a first-line treatment for patients with advanced epidermal growth factor receptor (EGFR) mutation-positive (m+) lung cancer. Drug-related pneumonitis (DRP) is a potentially lethal complication of osimertinib treatment, but reliable real-world data are currently lacking. We conducted a retrospective multicenter cohort study of patients who received osimertinib as a first-line treatment for advanced EGFR m+ non-small cell lung cancer (NSCLC) between August 2018 and December 2019. All chest computed tomography (CT) scans and clinical information during osimertinib exposure were collected until June 2020. The primary endpoint was DRP incidence identified through central review. A total of 452 patients from 18 institutions were evaluated. Eighty patients (18%) were diagnosed with DRP (all grades), and 21 patients (4.6%) had ≥grade 3 DRP. Among the patients with DRP, 46% were identified as having transient asymptomatic pulmonary opacity (TAPO). Regarding the CT patterns, organizing pneumonia, simple pulmonary eosinophilia, hypersensitivity pneumonia, diffuse alveolar damage, and non-specific interstitial pneumonia were found in 30, 21, 18, 9, and 2 patients (38%, 26%, 23%, 11%, and 3%), respectively. In multivariate analysis, smoking history was identified as an independent risk factor for DRP (hazard ratio: 1.72, 95% confidence interval: 1.01–2.89, P=0.046). In the 3-month landmark analysis, DRP was associated with poor treatment efficacy; however, the presence of TAPO did not negatively affect treatment efficacy. For osimertinib treatment in first-line settings, the frequency of DRP was considerably elevated to 18 %, and half of these patients exhibited TAPO features.

COVID-19 in Italy: Comparison of CT Findings from Time Zero to the Delta Variant.

On 12 March 2020, the World Health Organization (WHO) declared the novel Coronavirus (CoV) disease a global Pandemic and an emerging risk. In order to understand patterns that are typical in COVID-19 pneumonia and track the evolution of the disease, the role of the chest computed tomography (CT) is pivotal. The impact of the illness as well as the efficiency of the therapy are also monitored carefully when performing this imaging exam. Coronaviruses, specifically CoV-2, as RNA viruses, have a tendency to frequently change their genome, giving the virus beneficial characteristics such as greater transmissibility, pathogenicity and the possibility to escape the previously acquired immunity. Therefore, genome evaluation became an extremely important routine practice worldwide. In particular, in Italy, four variants have been recognised and each of them represent a specific temporal wave of the disease. Hence, our goal was to describe imaging findings of COVID-19 pneumonia, specifically its most typical imaging identified during the period of our study, and to assess whether or not SARS-CoV-2 variants determine different CT patterns. Our analyses revealed that the SARS-CoV-2 genotype seems not to interfere with the severity of CT patterns and, in particular, bilateral Ground Glass Opacities (GGOs) are the most frequent findings in all COVID-19 waves.

Pulmonary Sequelae in Patients After Recovery From Coronavirus Disease 2019: A Follow-Up Study With Chest CT.

Objective: The pulmonary sequelae of coronavirus disease 2019 (COVID-19) have not been comprehensively evaluated. We performed a follow-up study analyzing chest computed tomography (CT) findings of COVID-19 patients at 3 and 6 months after hospital discharge.Methods: Between February 2020 and May 2020, a total of 273 patients with COVID-19 at the Shenzhen Third People's Hospital were recruited and followed for 6 months after discharge. Chest CT scanning was performed with the patient in the supine position at end-inspiration. A total of 957 chest CT scans was obtained at different timepoints. A semi-quantitative score was used to assess the degree of lung involvement.Results: Most chest CT scans showed bilateral lung involvement with peripheral location at 3 and 6 months follow-up. The most common CT findings were ground-glass opacity and parenchymal band, which were found in 136 (55.3%) and 94 (38.2%) of the 246 patients at 3 months follow-up, and 82 (48.2%) and 76 (44.7%) of 170 patients at 6 months follow-up, respectively. The number of lobes involved and the total CT severity score declined over time. The total CT score gradually increased with the increasement of disease severity at both 3 months follow-up (trend test P < 0.001) and 6 months follow-up (trend test P < 0.001). Patients with different disease severity represented diverse CT patterns over time.Conclusions: The most common CT findings were ground-glass opacity and parenchymal bands at the 3 and 6 months follow-up. Patients with different disease severity represent diverse CT manifestations, indicating the necessary for long-term follow-up monitoring of patients with severe and critical conditions.

Idiopathic Chronic Eosinophilic Pneumonia Evolving to Pulmonary Fibrosis: A Retrospective Analysis.

Patients with idiopathic chronic eosinophilic pneumonia (ICEP) may have pulmonary fibrosis. To investigate the predictors of pulmonary fibrosis in ICEP, to describe the timeline of pulmonary fibrosis after ICEP diagnosis, and to detail the radiologic pattern of fibrosis. A retrospective computer-assisted search was performed to identify patients with ICEP seen at Mayo Clinic in Rochester, Minnesota, from January 1, 1997, through September 1, 2019. Patients with follow-up chest computed tomography (CT) beyond 12 months after the ICEP diagnosis were included in the study. Demographic, clinical, radiologic, and histopathologic characteristics were analyzed. Proportional hazards regression was used to assess the predictors of pulmonary fibrosis. We identified 62 patients (mean [SD] age at ICEP diagnosis, 60 [13] years; female sex, 37 [60%]). Cough (87%) and shortness of breath (85%) were the most common presenting symptoms. Of patients, 27 (44%) had a history of smoking and 27 (44%) had a history of asthma. During follow-up, 23 patients (37%) had CT evidence of pulmonary fibrosis, of whom 16 patients (70%) had a CT pattern inconsistent with usual interstitial pneumonia. In 29% of the patients, the CT evidence of pulmonary fibrosis developed within 2 years after ICEP. Age and male sex were predictors of pulmonary fibrosis. Of note, a history of asthma decreased the likelihood of pulmonary fibrosis. Development of pulmonary fibro-sis is not uncommon in patients with ICEP, especially older men, and is associated with increased risk of death.

Clinical and imaging findings of patients diagnosed with adenovirus-positive pneumonia during 2015-2019 in Shanghai, China.

This study was to describe the clinical characteristics, chest CT image findings, and potential role of T cells immunity in adenovirus positive pneumonia. In this retrospective study, medical records of 53 adult Adv+ patients who were admitted to the Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, from May 2015 to August 2019 were included. The presence of adenovirus and other respiratory viruses was detected using polymerase chain reaction of throat swabs samples. Clinical features and chest computed tomography (CT) findings were compared between patients with Adv+ pneumonia and Adv+ non-pneumonia. The top 3 most commonly occurring symptoms in Adv+ pneumonia patients were fever (66.7%), cough (63.3%), and tachypnea (16.7%). Patients with Adv+ pneumonia showed significantly higher rates of cough and fever and longer duration of hospitalization than patients with Adv+ non-pneumonia. In the Adv+ pneumonia group, consolidation (73.3%) was the most common imaging finding on chest CT scan, and the likelihood of involvement of bilateral lobes (60%) was high. Classical conspicuous consolidation with surrounding ground-glass opacity was observed in 5 (16.6%) patients with Adv+ pneumonia. Patients with Adv+ pneumonia showed a higher inhibition of T-cell immunity than did patients with Adv+ non-pneumonia, and counts of CD3+, CD4+, and CD8+ T-cells may predict the presence of pneumonia in Adv+ patients. With regard to Adv+ pneumonia, the most frequent symptoms were cough and fever, and the most common CT pattern was consolidation; classical CT findings such as consolidation with surrounding ground-glass opacity could also be observed. Furthermore, our data indicated the incidence of abrogated cellular immunity in patients with Adv+ pneumonia.

A prospective cohort study on radiological and physiological outcomes of recovered COVID-19 patients 6 months after discharge.

This study investigated patients' long-term radiological and physiological outcomes with coronavirus disease 2019 (COVID-19). A total of 52 patients (26 men and 26 women, 32 with moderate COVID-19 and 20 with severe COVID-19, with a median age of 50.5 years) who had COVID-19 participated in this study. Follow-up thin-section chest computed tomography (CT) scans were performed at 1, 3, and 6 months after discharge. Cardiopulmonary exercise testing was performed on 37 patients 6 months after discharge. The clinical data and the chest CT findings were recorded and analyzed. The predominant chest CT patterns of abnormalities observed at 6 months after discharge were parenchymal band, interlobular septal thickening, and traction bronchiectasis. The cumulative percentage of the complete radiological resolution was 17%, 42%, 67%, and 75% at discharge and 1, 3, and 6 months after discharge, respectively. A subgroup analysis revealed that 88% of patients with moderate type and 55% of patients with severe type COVID-19 achieved complete radiological resolution at 6 months after discharge, and the difference between the 2 groups was significant (P<0.001). The following risk factors were found to be associated with an incomplete radiological resolution at 6 months after discharge: an age >50 years old, the severe type of COVID-19, a hospital stay >18 days, mechanical ventilation, steroid therapy, immunoglobin therapy, an opacity score at discharge >4, and a volume of opacity at discharge >235 mL. Chest CT lesions were absorbed without any sequelae in most patients with COVID-19; however, fibrotic-like changes and cardiopulmonary insufficiency were still present in a considerable proportion of COVID-19 survivors at 6 months after discharge, especially in patients with severe type COVID-19.

Ultra-low-dose chest CT performance for the detection of viral pneumonia patterns during the COVID-19 outbreak period: a monocentric experience.

Ultra low dose chest computed tomography (CT) acquisitions have been used for selected emergency room patients with acute dyspnea or minor thoracic trauma. The purpose of this study was to evaluate the diagnostic performance of ultra-low-dose (ULD) chest CT for detecting viral pneumonia patterns compared to standard (STD) dose chest CT. All consecutive adult patients with two non-enhanced chest CT acquisitions, one STD and one ULD, for suspicion of viral pneumonia between March 5th and April 2nd 2020 were included. CT results were divided into two groups: non-viral pneumonia CT or compatible with viral pneumonia CT based on viral pneumonia CT patterns: ground-glass opacity (GGO), consolidation, crazy paving, air bronchogram signs and fibrous stripes. The diagnostic performance of ULD CT for suspicion of viral pneumonia was evaluated. For CTs compatible with viral pneumonia, CT pattern detection on ULD CT was assessed and STD CT was used as a reference. The study included 380 patients with 97 CTs (25.5%) compatible with viral pneumonia. The mean effective doses (EDs) were 1.66 (1.29; 2.18) mSv for STD and 0.20 (0.18; 0.22) mSv for ULD CT (P<0.001). The sensitivity and specificity of ULD CT for viral pneumonia detection were 98.9% and 99.0%, respectively. GGO, consolidation and fibrous stripes were equally visible in STD and ULD in 100% (n=97), 36% (n=35) and 23% (n=22) of compatible viral pneumonia-CT patients, respectively. Air bronchogram sign detection was equivalent, concerning 23% (n=22) of patients in STD and 22% (n=21) in ULD. Crazy paving was visible in 24% (n=23) of patients in STD and only 8% (n=8) in ULD (P=0.003). In comparison to STD dose chest CT, ULD chest CT, with a mean reduction dose of 88.0%, has comparable diagnostic performance for detecting viral pneumonia on CT.

COVID-19: Histopathological correlates of imaging patterns on chest computed tomography.

Background and objectivePatients with coronavirus disease 2019 (COVID‐19) pneumonia present with typical findings on chest computed tomography (CT), but the underlying histopathological patterns are unknown. Through direct regional correlation of imaging findings to histopathological patterns, this study aimed to explain typical COVID‐19 CT patterns at tissue level.MethodsEight autopsy cases were prospectively selected of patients with PCR‐proven COVID‐19 pneumonia with varying clinical manifestations and causes of death. All had been subjected to chest CT imaging 24–72 h prior to death. Twenty‐seven lung areas with typical COVID‐19 patterns and two radiologically unaffected pulmonary areas were correlated to histopathological findings in the same lung regions.ResultsTwo dominant radiological patterns were observed: ground‐glass opacity (GGO) (n = 11) and consolidation (n = 16). In seven of 11 sampled areas of GGO, diffuse alveolar damage (DAD) was observed. In four areas of GGO, the histological pattern was vascular damage and thrombosis, with (n = 2) or without DAD (n = 2). DAD was also observed in five of 16 samples derived from areas of radiological consolidation. Seven areas of consolidation were based on a combination of DAD, vascular damage and thrombosis. In four areas of consolidation, bronchopneumonia was found. Unexpectedly, in samples from radiologically unaffected lung parenchyma, evidence was found of vascular damage and thrombosis.ConclusionIn COVID‐19, radiological findings of GGO and consolidation are mostly explained by DAD or a combination of DAD and vascular damage plus thrombosis. However, the different typical CT patterns in COVID‐19 are not related to specific histopathological patterns. Microvascular damage and thrombosis are even encountered in the radiologically normal lung.

RSNA-STR-ACR Consensus Statement for COVID-19 CT Patterns: Interreader Agreement in 240 Consecutive Patients and Association With RT-PCR Status.

The aim of this study was to study interreader agreement of the RSNA-STR-ACR (Radiological Society of North America/Society of Thoracic Radiology/American College of Radiology) consensus statement on reporting chest computed tomography (CT) findings related to COVID-19 on a sample of consecutive patients confirmed with reverse transcriptase-polymerase chain reaction (RT-PCR) for severe acute respiratory syndrome coronavirus 2. This institutional review board-approved retrospective study included 240 cases with a mean age of 47.6 ± 15.9 years, ranging from 20 to 90 years, who had a chest CT and RT-PCR performed. Computed tomography images were independently analyzed by 2 thoracic radiologists to identify patterns defined by the RSNA-STR-ACR consensus statement, and concordance was determined with weighted κ tests. Also, CT findings and CT severity scores were tabulated and compared. Of the 240 cases, 118 had findings on CT. The most frequent on the RT-PCR-positive group were areas of ground-glass opacities (80.5%), crazy-paving pattern (32.2%), and rounded pseudonodular ground-glass opacities (22.9%). Regarding the CT patterns, the most frequent in the RT-PCR-positive group was typical in 75.9%, followed by negative in 17.1%. The interreader agreement was 0.90 (95% confidence interval, 0.80-0.96) in this group. The CT severity score had a mean difference of -0.07 (95% confidence interval, -0.48 to 0.34) among the readers, showing no significant differences regarding visual estimation. The RSNA-STR-ACR consensus statement on reporting chest CT patterns for COVID-19 presents a high interreader agreement, with the typical pattern being more frequently associated with RT-PCR-positive examinations.

Correlations between chest-CT and laboratory parameters in SARS-CoV-2 pneumonia: A single-center study from Italy.

To investigate the relationship between damaged lung assessed by chest computed tomography (CT) scan and laboratory biochemical parameters with the aim of finding other diagnostic tools.Patients who underwent chest CT for suspected Corona Virus Disease-2019 (COVID-19) pneumonia at the emergency department admission in the first phase of COVID-19 epidemic in Italy were retrospectively analyzed. Patients with both negative chest CT and absence of the novel coronavirus in nasopharyngeal or oropharyngeal real-time reverse transcriptase polymerase chain reaction (RT-PCR) swabs were excluded from the study. A total of 462 patients with positive CT scans for interstitial pneumonia were included in the study (250 males and 212 females, mean age 57 ± 17 years, range 18–89). Of these, 344 were positive to RT-PCR test, 118 were negative to double RT-PCR tests.CTs were analyzed for quantification of affected lung volume visually and by dedicated software. Statistical analysis to evaluate the relationship between laboratory analyses and CT patterns and amount of damaged lung related with COVID-19 pneumonia was performed in 2 groups of patients: positive RT-PCR COVID-19 group and negative RT-PCR COVID-19 group, but both with positive CT scans for interstitial pneumonia.Lymphocytopenia, C-reactive protein (CRP), lactate dehydrogenase (LDH), d-dimer, and fibrinogen increased levels occurred in most patients without statistically significant differences between the 2 groups with CT scans suggestive for COVID-19. In fact, in both groups the volume of lung damage was strongly associated with altered laboratory test results, even for patients with negative RT-PCR test.The decreased number of lymphocytes, and the increased levels of CRP, LDH, d-dimer, and fibrinogen levels are associated with SARS-CoV 2 related pneumonia. This may be useful as an additional diagnostic tool in patients with double negative RT-PCR assay and with highly suspected clinic and chest CT features for COVID-19 to isolate patients in a pandemic period.

Post-discharge chest CT findings and pulmonary function tests in severe COVID-19 patients

PurposeTo evaluate chest computed tomography (CT) and pulmonary function test (PFT) findings in severe COVID-19 patients after discharge and correlate CT pulmonary involvement with PFT results. MethodsCOVID-19 patients admitted to our hospital between February 25 and May 2, 2020, were retrospectively included according to the following criteria: (a) COVID-19 defined as severe based on the WHO interim guidance (i.e., clinical signs of pneumonia plus respiratory rate > 30 breaths/min, severe respiratory distress, and/or SpO2 < 90 % on room air); (b) chest radiograph in the acute setting; (c) post-discharge unenhanced chest CT; and (d) post-discharge comprehensive PFT. Imaging findings were retrospectively evaluated in consensus by two readers, and volume of abnormal lung was measured on CT using 3D Slicer software. Differences between demographics, comorbidities, acute radiographic findings, PFT, and post-discharge clinical and laboratory data of patients with normal and abnormal CT findings were assessed by Mann-Whitney or Fisher tests, and the compromised lung volume-PFT association by Pearson correlation after removing possible outliers. ResultsAt a median of 105 days from symptom onset, 74/91 (81 %) patients had CT abnormalities. The most common CT pattern was combined ground-glass opacity and reticular pattern (46/74, 62 %) along with architectural distortion (68/74, 92 %) and bronchial dilatation (66/74, 89 %). Compromised lung volume had a median value of 15 % [11–23], was higher in dyspneic patients, and negatively correlated with the percentage of predicted DLCO, VA, and FVC values (r = -0.39, -0.5, and -0.42, respectively). These PFT parameters were significantly lower in patients with CT abnormalities. Impairment of DLCO and KCO was found in 12 (13 %) cases, possibly implying an underlying pulmonary vasculopathy in this subgroup of patients. ConclusionsMost severe COVID-19 survivors still had physiologically relevant CT abnormalities about three months after the disease onset, with an impairment of diffusion capacity on PFT. A pulmonary vasculopathy was suggested in a minor proportion of patients.