Initial Reverse Transcription-polymerase Chain Reaction Research Articles

Diagnostic Performance Between Chest CT Severity Score and Initial Reverse Transcription-Polymerase Chain Reaction (RT-PCR) Cycle Values in COVID-19 Patients and Their Relation With the Clinical Status of Patients.

Reverse transcription-polymerase chain reaction (RT-PCR) is used as a standard test for the diagnosis of SARS-CoV-2 viral RNA from nasopharyngeal aspirates. However, this method lacks sensitivity and cannot assess disease severity. A CT scan of the thorax provides a CT severity score (CT-SS), which depicts lung involvement and disease severity. This study aims to investigate the diagnostic value of chest CT compared with RT-PCR cycle threshold (Ct) values in COVID-19 and relate it clinically with the disease severity of patients. This retrospective observational study was conducted in a tertiary center from April 2021 to March 2022. We included 511 patients who had tested RT-PCR positive for COVID-19, were hospitalized, and had undergone high-resolution CT (HRCT) thorax. Data was collected from patient records regarding name, age, sex, admission data, baseline investigations including Ct value, management, and outcome. HRCT was reviewed to assess lung involvement and calculate CT-SS. Data was analyzed using SPSS Statistics version 25 (IBM Corp. Released 2017. IBM SPSS Statistics for Windows, Version 25.0. Armonk, NY: IBM Corp.). The mean age of patients was 50.4 ± 13.7 years, and the majority (67.5%) were male. Gender-wise, there was no difference in RT-PCR cycle threshold (Ct) values; however, CT-SS was significantly higher in males (17.5 ± 4.8 vs.10.5 ± 6.6, t=-13.6, p<0.0001). ICU admission was needed for 34.8% of patients, and they had a significantly lower Ct value (21.7 ± 3.3 vs. 22.8 ± 3.7, t=21.10, p<0.0001) and higher CT-SS (16.3 ± 4.5 vs. 6.7 ± 5.1, t=-3.32, p=0.001). Ct values could not differentiate between moderate and severe patients. CT-SS was not related to the viral load at admission. Patients who succumbed had significantly lower Ct values and higher CT-SS.

Traditional Vietnamese Medicine Containing Garlic Extract for Patients With Non-severe COVID-19: A Phase-II, Double-Blind, Randomized Controlled Trial.

Background Coronavirus disease 2019 (COVID-19) is still ongoing with the omicron variant. Low-cost, effective treatments are still needed, particularly in low-to-middle-income countries. This study assessed the safety and efficacy of TD0068, an herbal medicine developed from mainly garlic, for patients with non-severe COVID-19. Methods This is a phase-II, double-blind, randomized controlled trial to compare oral capsule TD0068 and placebo in adults aged 18-65 years with non-severe COVID-19 between September and October 2021. The efficacy outcomes measured included daily cycle threshold (Ct) value from the time of the initial reverse transcription-polymerase chain reaction (RT-PCR) test, time to viral clearance, daily symptom severity score from 15 symptoms of interest, time to symptom resolution, and progression to severe/critical COVID-19. Safety outcomes included adverse events (AEs) and serious adverse events (SAEs). Results Sixty patients were randomized (31 received TD0068, and 29 received a placebo). The two groups were balanced in baseline characteristics: mean age was 39 years, and female was predominant (66%). Daily Ct value (median on days 3, 5, 7, and 9 was 25.7, 30.8, 35.4, and 37.6 in the TD0068 group, and 26.4, 31.2, 36.0, and 37.4 in the placebo group, respectively) and time to viral clearance (median: 10 vs. 11 days in TD0068 and placebo groups) were similar between groups. Daily symptom severity score (median on days 3, 5, 7, and 9 was 2, 2, 1, and 0 in the TD0068 group, and 3, 2, 1, and 1 in the placebo group), and time to symptom resolution (median: seven vs. nine days, respectively) were also comparable between groups. No SAE occurred in the study. Conclusions TD0068 is safe but does not show an effect for non-severe COVID-19 patients. Further research is needed to explore the potential benefits of garlic in other forms or dosages for the treatment of COVID-19.

HRCT CHEST EVALUATION OF SEQUELAE OF COVID-19 PNEUMONIA

Since December 2019, many unexplained cases of pneumonia have been reported, as a result of exposure in Wuhan city, Hubei province, China. The pathogen identied was coronavirus and the disease was named COVID-19 by World Health Organization (WHO). Based on the epidemiological surveys done, dry cough, fever and fatigue were the main clinical manifestations reported.(Huang et al., 2020; X. Liu et al., 2020) Few patients had symptoms such as runny nose, nasal obstruction, myalgia, sore throat, and diarrhoea. Seriously ill patients rapidly progressed to ARDS. The COVID-19 outbreak has been declared public health emergency of international concern by the WHO. A specic viral nucleic acid assay, real time reverse transcription-polymerase chain reaction (RT-PCR) was developed to diagnose COVID-19. However, published literature on COVID-19 pneumonia showed some patients with initial negative RT-PCR results. According to current literature, HRCT thorax may show abnormalities earlier than even RT-PCR(Zhou et al., 2020). Therefore, high resolution CT had been included as one of the main tools particularly for screening and in the evaluation of the severity of disease (Salameh et al., 2020) Although most of the patients showed complete resolution from illness, some of the them were likely to have some kind of long-term lung damage. Radiological ndings have proven to be helpful in estimating the course of the disease and they can be used to evaluate long-term consequences of the disease. CT had been recommended as an important tool for screening and also for evaluation of severity of the illness.(Dai et al., 2020; Shah et al., 2021) AIM: Ÿ Aim of the study was to determine the sequelae of COVID-19 pneumonia in positive patients 4 – 8 weeks after RT-PCR negative report. OBJECTIVE: Ÿ To describe the HRCT chest ndings of sequelae of COVID-19 pneumonia- GGO, brosis, bronchovascular bundle distortion and small pleural effusion. Ÿ To explore the relevant factors affecting the sequelae - initial clinical symptoms of onset, risk factors, age, and gender and laboratory examinations. Ÿ To determine the cumulative percentage of complete radiological resolution - using CT severity score

False-negative rate of SARS-CoV-2 RT-PCR tests and its relationship to test timing and illness severity: A case series.

ObjectiveTo determine the false-negative rate of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reverse-transcription polymerase chain reaction (RT-PCR) test results, and to describe the characteristics of coronavirus disease 2019 (COVID-19) patients with false-negative results.MethodsWe validated SARS-CoV-2-positive RT-PCR test results performed in hospitalized patients between February 1 and August 31, 2020 and classified the patients according to disease severity.ResultsIn total, 2038 SARS-CoV-2 RT-PCR tests were performed on 1890 patients. Of these, 145 patients had positive results and were diagnosed with COVID-19. Among the 145 patients with COVID-19, the initial RT-PCR tests were negative in five patients. Of these, three had moderate illness and were initially tested in the early stage of disease, and two had severe illness and were initially tested in the late stage of disease, when RT-PCR testing has lower sensitivity due to viral clearance.ConclusionsThese findings suggest that false-negative results can be caused by both observer errors and by low viral RNA levels in the later stages of disease, after the infection has cleared. Clinicians should be aware that patients with COVID-19 can have negative RT-PCR test results in the later stages of infection.

Exploring the Clinical Utility of Gustatory Dysfunction (GD) as a Triage Symptom Prior to Reverse Transcription Polymerase Chain Reaction (RT-PCR) in the Diagnosis of COVID-19: A Meta-Analysis and Systematic Review.

Background: The diagnosis of COVID-19 is made using reverse transcription polymerase chain reaction (RT-PCR) but its sensitivity varies from 20 to 100%. The presence of gustatory dysfunction (GD) in a patient with upper respiratory tract symptoms might increase the clinical suspicion of COVID-19. Aims: To perform a systematic review and meta-analysis to determine the pooled sensitivity, specificity, positive likelihood ratio (LR+), negative likelihood ratio (LR−) and diagnostic odds ratio (DOR) of using GD as a triage symptom prior to RT-PCR. Methods: PubMed and Embase were searched up to 20 June 2021. Studies published in English were included if they compared the frequency of GD in COVID-19 adult patients (proven by RT-PCR) to COVID-19 negative controls in case control or cross-sectional studies. The Newcastle-Ottawa scale was used to assess the methodological quality of the included studies. Results: 21,272 COVID-19 patients and 52,298 COVID-19 negative patients were included across 44 studies from 21 countries. All studies were of moderate to high risk of bias. Patients with GD were more likely to test positive for COVID-19: DOR 6.39 (4.86–8.40), LR+ 3.84 (3.04–4.84), LR− 0.67 (0.64–0.70), pooled sensitivity 0.37 (0.29–0.47) and pooled specificity 0.92 (0.89–0.94). While history/questionnaire-based assessments were predictive of RT-PCR positivity (DOR 6.62 (4.95–8.85)), gustatory testing was not (DOR 3.53 (0.98–12.7)). There was significant heterogeneity among the 44 studies (I2 = 92%, p < 0.01). Conclusions: GD is useful as a symptom to determine if a patient should undergo further testing, especially in resource-poor regions where COVID-19 testing is scarce. Patients with GD may be advised to quarantine while repeated testing is performed if the initial RT-PCR is negative. Funding: None.

Study of Thoracic CT in COVID-19: The STOIC Project.

BackgroundThere are conflicting data regarding the diagnostic performance of Chest computed tomography (CT) for COVID-19 pneumonia. Disease extent on CT has been reported to influence prognosis.PurposeTo create a large publicly available dataset and assess the diagnostic and prognostic value of CT in COVID-19 pneumonia.Materials and MethodsThis multicenter observational retrospective cohort study (ClinicalTrials.gov: NCT04355507) involved 20 French university hospitals. Eligible subjects presented at the emergency departments of the hospitals involved between March 1st and April 30th, 2020 and underwent both thoracic CT and RT-PCR for suspected COVID-19 pneumonia. CT images were read blinded to initial reports, RT-PCR, demographic characteristics, clinical symptoms, and outcome. Readers classified CT scans as positive or negative for COVID-19, based on criteria published by the French Society of Radiology. Multivariable logistic regression was used to develop a model predicting severe outcome (intubation or death) at 1-month follow-up in subjects positive for both RT-PCR and CT, using clinical and radiological features.ResultsOf 10,930 subjects screened for eligibility, 10,735 (median age 65 years, interquartile range, 51–77 years; 6,147 men) were included and 6,448 (60.0%) had a positive RT-PCR result. With RT-PCR as reference, the sensitivity and specificity and CT were 80.2% (95%CI: 79.3, 81.2) and 79.7% (95%CI: 78.5, 80.9), respectively with strong agreement between junior and senior radiologists (Gwet’s AC1 coefficient: 0.79) Of all the variables analysed, the extent of pneumonia on CT (OR 3.25, 95%CI: 2.71, 3.89) was the best predictor of severe outcome at one month. A score based solely on clinical variables predicted a severe outcome with an AUC of 0.64 (95%CI: 0.62, 0.66), improving to 0.69 (95%CI: 0.6, 0.71) when it also included the extent of pneumonia and coronary calcium score on CT.ConclusionUsing pre-defined criteria, CT reading is not influenced by reader’s experience and helps predict the outcome at one month.See also the editorial by Rubin.

Evaluation of potential COVID-19 recurrence in patients with late repeat positive SARS-CoV-2 testing.

BackgroundSARS-CoV-2 reinfection and reactivation has mostly been described in case reports. We therefore investigated the epidemiology of recurrent COVID-19 SARS-CoV-2.MethodsAmong patients testing positive for SARS-CoV-2 between March 11 and July 31, 2020 within an integrated healthcare system, we identified patients with a recurrent positive SARS-CoV-2 reverse transcription polymerase chain reaction (RT-PCR) assay ≥60 days after an initial positive test. To assign an overall likelihood of COVID-19 recurrence, we combined quantitative data from initial and recurrent positive RT-PCR cycle thresholds—a value inversely correlated with viral RNA burden— with a clinical recurrence likelihood assigned based on independent, standardized case review by two physicians. “Probable” or “possible” recurrence by clinical assessment was confirmed as the final recurrence likelihood only if a cycle threshold value obtained ≥60 days after initial testing was lower than its preceding cycle threshold or if the patient had an interval negative RT-PCR.ResultsAmong 23,176 patients testing positive for SARS-CoV-2, 1,301 (5.6%) had at least one additional SARS-CoV-2 RT-PCRs assay ≥60 days later. Of 122 testing positive, 114 had sufficient data for evaluation. The median interval to the recurrent positive RT-PCR was 85.5 (IQR 74–107) days. After combining clinical and RT-PCR cycle threshold data, four patients (3.5%) met criteria for probable COVID-19 recurrence. All four exhibited symptoms at recurrence and three required a higher level of medical care compared to their initial diagnosis. After including six additional patients (5.3%) with possible recurrence, recurrence incidence was 4.3 (95% CI 2.1–7.9) cases per 10,000 COVID-19 patients.ConclusionsOnly 0.04% of all COVID-19 patients in our health system experienced probable or possible recurrence; 90% of repeat positive SARS-CoV-2 RT-PCRs were not consistent with true recurrence. Our pragmatic approach combining clinical and quantitative RT-PCR data could aid assessment of COVID-19 reinfection or reactivation by clinicians and public health personnel.

Chest CT Diagnosis of COVID-19: Accuracy using CO-RADS and CT-Involvement Scoring.

Objectives:Both Reporting and Data System (CO-RADS) and CT-involvement scores (CTIS) have been proposed for evaluation of COVID-19 on chest CT. The purpose of this single-center, retrospective study was to evaluate both scoring systems to diagnose COVID-19 infection in a high-prevalence area.Materials and Methods:Chest CT datasets (n = 200) and available reverse transcription polymerase chain reaction (RT-PCR) on nasopharyngeal swab were included. CT scans were assigned to four ‘imaging groups’ after scoring for both CO-RADS and CTIS. Diagnostic accuracy of chest CT was calculated respectively using RT-PCR and clinical diagnosis as gold standards: False-negatives and false-positives of chest CT regarding RT-PCR were studied in more depth using the medical files.Results:The ‘imaging group’ including CO-RADS 4/5 scores reached the highest diagnostic values for COVID-19 considering either the initial RT-PCR or the final clinical diagnosis as the standard of reference: accuracies of 172/200 (86%) to 181/200 (90.5%), sensitivities of 60/80 (88.2%) to 70/79 (88.6%), specificities of 112/132 (84.9%) to 111/121 (91.7%), negative predictive values (NPV) of 112/120 (93.3%) to 111/120 (92.5%), respectively. False-negative CTs regarding RT-PCR were mainly explained by imaging very early in the disease course (5 out of 8 cases) or COVID-19 infection with no/minor respiratory symptoms (3 out of 8 cases).Conclusion:Assessing chest CT using CO-RADS is a valuable diagnostic approach for COVID-19 infection in a high-prevalence area, with a higher accuracy than CTIS.

Proactive Measures to Combat a SARS-CoV-2 Transmission Among High Risk Patients and Health Care Workers in an Outpatient Dialysis Facility.

Background: End-stage-renal-failure (ESRF) patients attending clustered out-patient dialysis are susceptible to SARS-CoV-2 infection. Comorbidities render them vulnerable to severe COVID-19. Although preventative and mitigation strategies are recommended, the effect of these are unknown. A period of “potential-high-infectivity” results if a health-care-worker (HCWs) or a patient becomes infected. Aim: We describe and analyze early, universal SARS-CoV-2 real time reverse transcription polymerase chain reaction (RT-PCR) tests, biomarker monitoring and SARS-CoV-2 preventative strategies, in a single dialysis center, after a positive patient was identified. Methodology: The setting was a single outpatient dialysis center in Johannesburg, South Africa which had already implemented preventative strategies. We describe the management of 57 patients and 11 HCWs, after one of the patients tested positive for SARS-CoV-2. All individuals were subjected to RT-PCR tests and biomarkers (Neutrophil-Lymphocyte Ratio, C-reactive protein, and D-Dimer) within 72 h (initial-tests). Individuals with initial negative RT-PCR and abnormal biomarkers (one or more) were subjected to repeat RT-PCR and biomarkers (retest subgroup) during the second week. Additional stringent measures (awareness of viral transmission, dialysis distancing and screening) were implemented during the period of “potential high infectivity.” The patient retest subgroup also underwent clustered dialysis until retest results became available. Results: A second positive-patient was identified as a result of early universal RT-PCR tests. In the two positive-patients, biomarker improvement coincided with RT-PCR negative tests. We identified 13 individuals for retesting. None of these retested individuals tested positive for SARS-CoV-2 and there was no deterioration in median biomarker values between initial and retests. Collectively, none of the negative individuals developed COVID-19 symptoms during the period “potential high infectivity.” Conclusion: A SARS-CoV-2 outbreak may necessitate additional proactive steps to counteract spread of infection. This includes early universal RT-PCR testing and creating further awareness of the risk of transmission and modifying preventative strategies. Abnormal biomarkers may be poorly predictive of SARS-CoV-2 infection in ESRF patients due to underlying illnesses. Observing dynamic changes in biomarkers in RT-PCR positive and negative-patients may provide insights into general state of health.

The Association Between Antibody Response to Severe Acute Respiratory Syndrome Coronavirus 2 Infection and Post-COVID-19 Syndrome in Healthcare Workers.

It is currently unknown how post-COVID-19 syndrome (PCS) may affect those infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This longitudinal study includes healthcare staff who tested positive for SARS-CoV-2 between March and April 2020, with follow-up of their antibody titers and symptoms. More than half (21 of 38) had PCS after 7–8 months. There was no statistically significant difference between initial reverse-transcription polymerase chain reaction titers or serial antibody levels between those who did and those who did not develop PCS. This study highlights the relative commonality of PCS in healthcare workers and this should be considered in vaccination scheduling and workforce planning to allow adequate frontline staffing numbers.

Systematic Screening of COVID-19 Disease Based on Chest CT and RT-PCR for Cancer Patients Undergoing Radiation Therapy in a Coronavirus French Hotspot.

PurposePatients with cancer are presumed to be more vulnerable to COVID-19. We evaluated a screening strategy combining chest computed tomography (CT) and reverse-transcription polymerase chain reaction (RT-PCR) for patients treated with radiation therapy at our cancer center located in a COVID-19 French hotspot during the first wave of the pandemic.Methods and MaterialsChest CT images were proposed during radiation therapy CT simulation. Images were reviewed by an expert radiologist according to the COVID-19 Reporting and Data System classification. Nasal swabs with RT-PCR assay were initially proposed in cases of suspicious imaging or clinical context and were eventually integrated into the systematic screening. A dedicated radiation therapy workflow was proposed for COVID-19 patients to limit the risk of contamination.ResultsFrom March 18, 2020 to May 1, 2020, 480 patients were screened by chest CT, and 313 patients had both chest CT and RT-PCR (65%). The cumulative incidence of COVID-19 was 5.4% (95% confidence interval [CI], 3.6-7.8; 26 of 480 patients). Diagnosis of COVID-19 was made before radiation therapy for 22 patients (84.6%) and during RT for 4 patients (15.3%). Chest CT directly aided the diagnosis of 7 cases in which the initial RT-PCR was negative or not feasible, out of a total of 480 patients (1.5%) and 517 chest CT acquisitions. Four patients with COVID-19 at the time of the chest CT screening had a false negative CT. Sensitivity and specificity of chest CT screening in patients with both RT-PCR and chest CT testing were estimated at 0.82 (95% CI, 0.60-0.95) and 0.98 (95% CI, 0.96-0.99), respectively. Adaptation of the radiation therapy treatment was made for all patients, with 7 postponed treatments (median: 5 days; interquartile range, 1.5-14.8).ConclusionsThe benefit of systematic use of chest CT screening during CT simulation for patients undergoing radiation therapy during the COVID-19 pandemic seemed limited.

Application of Mobile Helical Computed Tomography in Combatting COVID-19

Background: Chest computed tomography (CT) is a recommended screening and assessment tool for patients with suspected coronavirus disease (COVID-19). However, CT units are currently not available in many temporary hospitals and centralized isolation places. Objectives: To delineate the workflow of mobile CT unit and evaluate its role in screening for COVID-19 infection in temporary hospitals and centralized isolation locations. Patients and Methods: Two hundred and twenty-three patients under medical observation in temporary centralized isolation were enrolled in this study. All patients underwent reverse-transcription polymerase chain reaction (RT-PCR) testing and mobile CT chest examinations. Communication, storage, and browsing of CT data were performed with 4G and cloud technology. Image quality and radiation dose were evaluated and compared with a commercial conventional 64-row CT scanner. Additionally, the sensitivity of initial chest CT and the initial RT-PCR for COVID-19 were compared. Results: CT examination of 223 patients was completed within 19 work hours. Communication, storage, and browsing of CT data via 4G and cloud technology were seamless. There were no significant differences in subjective image quality scores between groups (P &gt; 0.05). COVID-19 pneumonia was eventually confirmed in 49 patients (21.97%). The sensitivity of initial chest CT was greater than that of the initial RT-PCR (85.71% and 67.35%, respectively) (P &lt; 0.05). Conclusion: Screening suspected patients for COVID-19 by mobile CT in temporary hospitals and isolation points is a simple, efficient, and highly sensitive technique for early diagnosis and control of COVID-19.

Neutralizing antibody titres in SARS-CoV-2 infections

The SARS-CoV-2 pandemic poses the greatest global public health challenge in a century. Neutralizing antibody is a correlate of protection and data on kinetics of virus neutralizing antibody responses are needed. We tested 293 sera from an observational cohort of 195 reverse transcription polymerase chain reaction (RT-PCR) confirmed SARS-CoV-2 infections collected from 0 to 209 days after onset of symptoms. Of 115 sera collected ≥61 days after onset of illness tested using plaque reduction neutralization (PRNT) assays, 99.1% remained seropositive for both 90% (PRNT90) and 50% (PRNT50) neutralization endpoints. We estimate that it takes at least 372, 416 and 133 days for PRNT50 titres to drop to the detection limit of a titre of 1:10 for severe, mild and asymptomatic patients, respectively. At day 90 after onset of symptoms (or initial RT-PCR detection in asymptomatic infections), it took 69, 87 and 31 days for PRNT50 antibody titres to decrease by half (T1/2) in severe, mild and asymptomatic infections, respectively. Patients with severe disease had higher peak PRNT90 and PRNT50 antibody titres than patients with mild or asymptomatic infections. Age did not appear to compromise antibody responses, even after accounting for severity. We conclude that SARS-CoV-2 infection elicits robust neutralizing antibody titres in most individuals.

False-negative results of initial RT-PCR assays for COVID-19: A systematic review.

BackgroundA false-negative case of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is defined as a person with suspected infection and an initial negative result by reverse transcription-polymerase chain reaction (RT-PCR) test, with a positive result on a subsequent test. False-negative cases have important implications for isolation and risk of transmission of infected people and for the management of coronavirus disease 2019 (COVID-19). We aimed to review and critically appraise evidence about the rate of RT-PCR false-negatives at initial testing for COVID-19.MethodsWe searched MEDLINE, EMBASE, LILACS, as well as COVID-19 repositories, including the EPPI-Centre living systematic map of evidence about COVID-19 and the Coronavirus Open Access Project living evidence database. Two authors independently screened and selected studies according to the eligibility criteria and collected data from the included studies. The risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. We calculated the proportion of false-negative test results using a multilevel mixed-effect logistic regression model. The certainty of the evidence about false-negative cases was rated using the GRADE approach for tests and strategies. All information in this article is current up to July 17, 2020.ResultsWe included 34 studies enrolling 12,057 COVID-19 confirmed cases. All studies were affected by several risks of bias and applicability concerns. The pooled estimate of false-negative proportion was highly affected by unexplained heterogeneity (tau-squared = 1.39; 90% prediction interval from 0.02 to 0.54). The certainty of the evidence was judged as very low due to the risk of bias, indirectness, and inconsistency issues.ConclusionsThere is substantial and largely unexplained heterogeneity in the proportion of false-negative RT-PCR results. The collected evidence has several limitations, including risk of bias issues, high heterogeneity, and concerns about its applicability. Nonetheless, our findings reinforce the need for repeated testing in patients with suspicion of SARS-Cov-2 infection given that up to 54% of COVID-19 patients may have an initial false-negative RT-PCR (very low certainty of evidence).Systematic review registrationProtocol available on the OSF website: https://tinyurl.com/vvbgqya.

CT FINDINGS IN INITIAL RT-PCR NEGATIVE TESTING COVID 19: BASED ON STUDY IN A LARGEST TERTIARY CARE CENTRE OF CENTRAL INDIA.

SUMMARY STATEMENT CT imaging findings in patients of suspected 2019-nCoV infection, who have initial negative results of reverse transcription–polymerase chain reaction (RT-PCR) testing. OBJECTIVE The purpose of this study is to explore the diagnostic value of CT over RT-PCR in the diagnosis of corona virus disease (COVID-19) pneumonia, especially for patients who have initial negative results of reverse transcription–polymerase chain reaction (RT-PCR) testing. MATERIALS AND METHODS Patients with suspected COVID-19 pneumonia from April 1, 2020, to September 30, 2020, were included. They are initially underwent RT-PCR followed by HRCT thorax after 1 day of negative initial RT-PCR testing. The imaging findings were obtained and compared with CT findings of those patients who have confirmed initial reverse transcription–polymerase chain reaction (RT-PCR) testing. RESULTS Total sixty (40 men, 20 women) patients who have initial negative RT-PCR testing but are highly suspicious for 2019-nCoV infection were included in our study and their age range between 22 years to 70 years. In our study most of the findings were seen involved the multiple( 70%) lobes in both lungs. The main CT features were ground-glass opacity (90%) and consolidation (60%) with a sub pleural (100%) and peri hilar or central distribution. The other CT features included air bronchograms (60%), vascular enlargement and interlobular septal thickening (50%), tree in bud appearance and pleural effusions (10%). when CT of patient with initial negative RT-PCR test were compared with CT of patients with initial positive RT-PCR test , it was found that most of the findings like ground glass opacities and consolidatory changes were also likely present in these group (p&gt;0.05). CONCLUSION Chest CT is an important tools for screening and diagnosing the patients who are initial negative RT-PCR however they are highly suspicious and having symptoms like 2019-nCoV infection.

Clinical application of the COVID-19 Reporting and Data System (CO-RADS) in patients with suspected SARS-CoV-2 infection: observational study in an emergency department

• CO-RADS improves the risk classification by 65.8% in patients affected by COVID-19. • CO-RADS combined with RT-PCR presents an AUC of 0.98 for patients with COVID-19. • CO-RADS improves the risk classification by 82.1% in patients not affected by COVID-19.

Managing high clinical suspicion COVID-19 inpatients with negative RT-PCR: a pragmatic and limited role for thoracic CT

As the COVID-19 pandemic sweeps across the UK there remain issues with reverse-transcription polymerase chain reaction (RT-PCR), the gold standard diagnostic method. Delays in obtaining results have been particularly problematic....

Reporting radiographers' interpretation and use of the British Society of Thoracic Imaging's coding system when reporting COVID-19 chest x-rays

IntroductionThe United Kingdom (UK) has experienced one of the worst initial waves of the COVID-19 pandemic. Clinical signs help guide initial diagnosis, though definitive diagnosis is made using the laboratory technique reverse transcription polymerase chain reaction (RT-PCR). The chest x-ray (CXR) is used as the primary imaging investigation in the United Kingdom (UK) for patients with suspected COVID-19. In some hospitals these CXRs may be reported by a radiographer. MethodsRetrospective review of CXR reports by radiographers for suspected COVID-19 patients attending the Emergency Department (ED) of a hospital in the UK. Interpretation and use of the British Society of Thoracic Imaging (BSTI) coding system was assessed. Report description and code use were cross-checked. Report and code usage were checked against the RT-PCR result to determine accuracy. Report availability was checked against the availability of the RT-PCR result. A confusion matrix was utilised to determine performance. The data were analysed manually using Excel. ResultsSample size was 320 patients; 54.1% male patients (n = 173), 45.9% female patients (n = 147). The correct code matched report descriptions in 316 of the 320 cases (98.8%). In 299 of the 320 cases (93.4%), the reports were available before the RT-PCR swab result. CXR sensitivity for detecting COVID-19 was 85% compared to 93% for the initial RT-PCR. ConclusionReporting radiographers can adequately utilise and apply the BSTI classification system when reporting COVID-19 CXRs. They can recognise the classic CXR appearances of COVID-19 and those with normal appearances. Future best practice includes checking laboratory results when reporting CXRs with ambiguous appearances. Implications for practiceUtilisation of reporting radiographers to report CXRs in any future respiratory pandemic should be considered a service-enabling development.

Characterization of Paralichthys olivaceus peroxisome proliferator-activated receptor-α gene as a master regulator of flounder lipid metabolism

Peroxisome proliferator-activated receptors (PPARs) are nuclear hormone receptors that play key roles in lipid and energy homeostasis. Paralichthys olivaceus PPARα (PoPPARα) cDNA was isolated by initial reverse transcription-polymerase chain reaction (RT-PCR) using conserved region among fish species and rapid amplification of cDNA ends (RACE). The full-length of PoPPARα cDNA is 2040-bp long encoding a polypeptide with 505 amino acids and containing a DNA binding domain (C4-type zinc finger) and a ligand-binding domain. PoPPARα was detected from 1 day post-hatch and was highly expressed in the stomach, liver, and intestine of continuously fed flounder, approximately 16 cm in size. PoPPARα mRNA expression was down-regulated in the kidney, stomach, and liver of the 4.5-month-old flounder after a 30 day food-deprivation period. PoPPARα activates the PPAR response element (PPRE)-driven reporter, and treatment with Wy14643, a PPARα agonist, augmented PoPPARα-stimulated peroxisome proliferator response element activity in HINAE and HepG2 cells. PoPPARα activated the expression of fatty acid β-oxidation related genes such as carnitine palmitoyltransferase 1A, medium chain acyl-CoA dehydrogenase, and acyl-CoA oxidase 1 and inhibited the expression of sterol regulatory element binding protein and fatty acid synthase by competitively inhibiting LXR/RXR heterodimer formation. These results suggest that PoPPARα plays an important role in lipid metabolism of olive flounder and that it is functionally and evolutionarily conserved in olive flounder and mammals.

Detection of Rhinovirus in Turbinate Epithelial Cells of Chronic Sinusitis

In contrast to the well-established association of rhinovirus (RV) with acute sinusitis, little is known about the role of RV infections in the pathogenesis of chronic sinusitis. Therefore, we assayed the nasal cavity mucosae of chronic sinusitis patients lacking signs of acute viral infection for the presence of RV. Nasal lavage fluids and turbinate epithelial cells from 39 sinusitis patients and 27 control subjects were tested. Turbinate epithelial cells were collected using a Rhino-probe mucosal curette. Picornavirus was assayed by an initial reverse-transcription polymerase chain reaction (PCR), and picornavirus-positive samples were assayed by nested reverse-transcription PCR to detect RV. All lavage fluids from both groups, as well as control epithelial cells, were negative for picornavirus. In contrast, 8 of 39 (21%) epithelial cell samples from sinusitis patients were positive for picornavirus. RV-specific nested-PCR revealed that all eight of these samples were positive for RV. The detection of RV in the turbinate epithelial cells of chronic sinusitis patients suggests that RV may be important in the pathogenesis of chronic sinusitis.