scholarly journals COVID-19 pneumonia: a pictorial review of CT findings and differential diagnosis

2021 ◽  
Vol 52 (1) ◽  
Author(s):  
Fattane Shirani ◽  
Azin Shayganfar ◽  
Somayeh Hajiahmadi
Keyword(s):  
Differential Diagnosis ◽  
Ct Scan ◽  
Screening Tool ◽  
False Negative ◽  
Imaging Findings ◽  
Rt Pcr ◽  
Negative Results ◽  
Ct Findings ◽  
Pictorial Review ◽  
False Negative Results

Abstract Background The gold standard for verifying COVID-19 mostly depends on microbiological tests like real-time polymerase chain reaction (RT-PCR). However, the availability of RT-PCR kits can be known as a problem and false negative results may be encountered. Although CT scan is not a screening tool for the diagnosis of COVID-19 pneumonia, given the widespread acquisition of it in the pandemic state, familiarity with different CT findings and possible differential diagnosis is essential in this regard. Main text In this review, we introduced the typical and atypical CT features of COVID-19 pneumonia, and discussed the main differential diagnosis of COVID-19 pneumonia. Conclusions The imaging findings in this viral pneumonia showed a broad spectrum, and there are no pathognomonic imaging findings for COVID-19 pneumonia. Although CT scan is not a diagnostic and screening tool, familiarity with different imaging findings and their differential diagnosis can be helpful in a rapid and accurate decision-making.

COVID-19: how nuclear medicine can provide a differential diagnosis in very dubious case

Coronaviruses ◽  
2020 ◽  
Vol 01 ◽  
Author(s):  
Maria Silvia De Feo ◽  
Viviana Frantellizzi ◽  
Giuseppe De Vincentis
Keyword(s):  
Infectious Disease ◽  
Differential Diagnosis ◽  
Ct Scan ◽  
Imaging Technique ◽  
False Negative ◽  
Clinical Signs ◽  
Negative Results ◽  
Infectious Disease Department ◽  
False Negative Results ◽  
99Mtc Hmpao

Background: We present the case of a 55-year-old woman, admitted to the Infectious Disease Department of Policlinico Umberto I, Rome, in mid-March 2020, with suspicion of COVID-19 infection. Objective: The rRT-PCR was negative and the following CT scan, performed to exclude false-negative results and help diagnosis, was inconclusive. Methods: It was decided to submit the patient to 99mTc-HMPAO-labelled leukocyte scan. Results: This exam led to the diagnosis of infective endocarditis. Conclusion: In the present pandemic scenario, 99mTc-HMPAO-labelled leukocyte scan represents a reliable imaging technique for differential diagnosis with COVID-19 in patients with confusing clinical signs, possible false-negative rRT-PCR results and inconclusive CT scan.

COVID-19 Detection on Chest X-Ray and CT Scan Images Using Multi-image Augmented Deep Learning Model

2020 ◽  
Author(s):  
Kiran Purohit ◽  
Abhishek Kesarwani ◽  
Dakshina Ranjan Kisku ◽  
Mamata Dalui
Keyword(s):  
Ct Scan ◽  
False Negative ◽  
Radical Change ◽  
Testing Time ◽  
Rt Pcr ◽  
X Ray ◽  
Negative Results ◽  
False Negative Results ◽  
Chest X Ray ◽  
Coronavirus Infection

AbstractCOVID-19 is posed as very infectious and deadly pneumonia type disease until recent time. Despite having lengthy testing time, RT-PCR is a proven testing methodology to detect coronavirus infection. Sometimes, it might give more false positive and false negative results than the desired rates. Therefore, to assist the traditional RT-PCR methodology for accurate clinical diagnosis, COVID-19 screening can be adopted with X-Ray and CT scan images of lung of an individual. This image based diagnosis will bring radical change in detecting coronavirus infection in human body with ease and having zero or near to zero false positives and false negatives rates. This paper reports a convolutional neural network (CNN) based multi-image augmentation technique for detecting COVID-19 in chest X-Ray and chest CT scan images of coronavirus suspected individuals. Multi-image augmentation makes use of discontinuity information obtained in the filtered images for increasing the number of effective examples for training the CNN model. With this approach, the proposed model exhibits higher classification accuracy around 95.38% and 98.97% for CT scan and X-Ray images respectively. CT scan images with multi-image augmentation achieves sensitivity of 94.78% and specificity of 95.98%, whereas X-Ray images with multi-image augmentation achieves sensitivity of 99.07% and specificity of 98.88%. Evaluation has been done on publicly available databases containing both chest X-Ray and CT scan images and the experimental results are also compared with ResNet-50 and VGG-16 models.

Scoring System for the Diagnosis of COVID-19

2020 ◽  
Vol 13 (1) ◽  
pp. 413-414 ◽  
Author(s):  
Mohamed Farouk Allam
Keyword(s):  
Scoring System ◽  
Clinical Symptoms ◽  
False Negative ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Negative Results ◽  
False Negative Results ◽  
Symptoms And Signs

Due to the international spread of COVID-19, the difficulty of collecting nasopharyngeal swab specimen from all suspected patients, the costs of RT-PCR and CT, and the false negative results of RT-PCR assay in 41% of COVID-19 patients, a scoring system is needed to classify the suspected patients in order to determine the need for follow-up, home isolation, quarantine or the conduction of further investigations. A scoring system is proposed as a diagnostic tool for suspected patients. It includes Epidemiological Evidence of Exposure, Clinical Symptoms and Signs, and Investigations (if available). This scoring system is simple, could be calculated in a few minutes, and incorporates the main possible data/findings of any patient.

scholarly journals Superiority of MALDI-TOF Mass Spectrometry over Real-Time PCR for SARS-CoV-2 RNA Detection

Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 730
Author(s):  
Magda Rybicka ◽  
Ewa Miłosz ◽  
Krzysztof Piotr Bielawski
Keyword(s):  
Mass Spectrometry ◽  
Gold Standard ◽  
Viral Genome ◽  
False Negative ◽  
Rt Pcr ◽  
Rna Detection ◽  
Maldi Tof ◽  
Negative Results ◽  
False Negative Results ◽  
Pcr Test

At present, the RT-PCR test remains the gold standard for early diagnosis of SARS-CoV-2. Nevertheless, there is growing evidence demonstrating that this technique may generate false-negative results. Here, we aimed to compare the new mass spectrometry-based assay MassARRAY® SARS-CoV-2 Panel with the RT-PCR diagnostic test approved for clinical use. The study group consisted of 168 suspected patients with symptoms of a respiratory infection. After simultaneous analysis by RT-PCR and mass spectrometry methods, we obtained discordant results for 17 samples (10.12%). Within fifteen samples officially reported as presumptive positive, 13 were positive according to the MS-based assay. Moreover, four samples reported by the officially approved RT-PCR as negative were positive in at least one MS assay. We have successfully demonstrated superior sensitivity of the MS-based assay in SARS-CoV-2 detection, showing that MALDI-TOF MS seems to be ideal for the detection as well as discrimination of mutations within the viral genome.

scholarly journals Distribution of SARS-CoV-2 PCR Cycle Threshold Values Provide Practical Insight Into Overall and Target-Specific Sensitivity Among Symptomatic Patients

2020 ◽  
Vol 154 (4) ◽  
pp. 479-485 ◽  
Author(s):  
Blake W Buchan ◽  
Jessica S Hoff ◽  
Cameron G Gmehlin ◽  
Adriana Perez ◽  
Matthew L Faron ◽  
...  
Keyword(s):  
Viral Load ◽  
Limit Of Detection ◽  
False Negative ◽  
Age Group ◽  
Rt Pcr ◽  
Patient Age ◽  
Cycle Threshold ◽  
Negative Results ◽  
Patient Âgé ◽  
False Negative Results

Abstract Objectives We examined the distribution of reverse transcription polymerase chain reaction (RT-PCR) cycle threshold (CT) values obtained from symptomatic patients being evaluated for coronavirus disease 2019 (COVID-19) to determine the proportion of specimens containing a viral load near the assay limit of detection (LoD) to gain practical insight to the risk of false-negative results. We also examined the relationship between CT value and patient age to determine any age-dependent difference in viral load or test sensitivity. Methods We collected CT values obtained from the cobas severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) assay corresponding to 1,213 combined nasopharyngeal-oropharyngeal specimens obtained from symptomatic individuals that were reported as positive or presumptive positive for SARS-CoV-2. CT values were stratified by SARS-CoV target and patient age group. Results In total, 93.3% to 98.4% of specimens demonstrated CT values greater than 3× the assay LoD, at which point false-negative results would not be expected. The mean of CT values between age groups was statistically equivalent with the exception of patients in age group 80 to 89 years, which demonstrated slightly lower CTs. Conclusions Based on the distribution of observed CT values, including the small proportion of specimens with values near the assay LoD, there is a low risk of false-negative RT-PCR results in combined nasopharyngeal-oropharyngeal specimens obtained from symptomatic individuals.

scholarly journals Reducing False Negative PCR Test for COVID-19

2020 ◽  
Vol 9 (3) ◽  
pp. 408-410
Author(s):  
Fatemeh Bahreini ◽  
Rezvan Najafi ◽  
Razieh Amini ◽  
Salman Khazaei ◽  
Saeid Bashirian
Keyword(s):  
Polymerase Chain Reaction ◽  
Real Time ◽  
False Negative ◽  
Rt Pcr ◽  
Chain Reaction ◽  
Creative Commons ◽  
Negative Results ◽  
False Negative Results ◽  
Polymerase Chain ◽  
Pcr Test

As the SARS-CoV-2 (COVID-19) pandemic spreads rapidly, there is need for a diagnostic test with high accuracy to detect infected individuals especially those without symptoms. Real-time polymerase chain reaction (RT-PCR) is a common molecular test for diagnosing SARS-CoV-2. If some factors are not taken into consideration when performing this test, it can have a relatively large number of false negative results. In this article, we discuss important considerations that could lead to false negative test reduction. Key words: • SARS-CoV-2 • COVID-19 • Real time polymerase chain reaction • RT-PCR test • Diagnosis • False negatives • Genetics • Emerging disease   Copyright © 2020 Bahreini et al. Published by Global Health and Education Projects, Inc. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0)which permits unrestricted use, distribution, and reproduction in any medium, provided the original work, first published in this journal, is properly cited.

scholarly journals Evaluation of chest computed tomography features in COVID-19: a single-center retrospective study

2021 ◽  
Vol 4 (4) ◽  
pp. 588-594
Author(s):  
Akshat Sanjay Shukla ◽  
Sanjay Rajendraprasad Shukla ◽  
Feral Ravi Daruwala
Keyword(s):  
Computed Tomography ◽  
Ct Scan ◽  
False Negative ◽  
Chest Ct ◽  
Single Center ◽  
Rt Pcr ◽  
Pulmonary Vessel ◽  
Ct Findings ◽  
Diagnostic Center ◽  
Second Wave

Background: Even though Real-Time Polymerase Chain Reaction (RT-PCR) is a gold standard for confirming COVID-19, it continues to be plagued by a lack of RT-PCR kits and the potential of false-negative results. Hence, during the second wave of COVID-19 in India, Computed Tomography (CT) scan is an emerging diagnostic tool in evaluating the severity of illness in COVID-19 pneumonia. The present study endeavored to assess chest CT features of COVID-19 pneumonia in Indian population. Methods: This was a single-center, retrospective, observational study conducted in 300 consecutive adults RT-PCR confirmed COVID-19 patients from 1, Jan 2021 to 31, March 2021 at a private radio diagnostic center.  Data regarding baseline demographics, clinical and laboratory characteristics, extent, pattern, and type of abnormal CT findings were noted. Results: The study population (204 males and 108 females) had mean age of 43.18 ± 8.27 years.  Our study's most common clinical presentation was cough (48.1%) and fever (47.1%), respectively. Lung parenchymal abnormalities were found in 294 (94.2%) patients. Abnormal CT findings revealed the involvement of bilateral (45.6%) and multilobar (42.9%) with a predominant peripheral (92.3%) and posterior (80.8%) distribution. According to the type of opacity, Ground Glass Opacity (GGO) was the dominant abnormality found in 270 (91.8%) patients, in which pure GGO (36.7%), GGO with crazy paving pattern (39.8%), and GGO mixed with consolidation (52.0 %) were noted. Peri-lesional or intralesional segmental or subsegmental pulmonary vessel enlargement was found in 192 (65.3 %) patients. Conclusion: During the second wave of COVID-19, a chest CT scan is a modality of choice in diagnosing COVID-19 pneumonia and related lung parenchymal changes.

scholarly journals False-Negative Nasopharyngeal Swab RT-PCR Assays in Typical COVID-19: Role of Ultra-low-dose Chest CT and Bronchoscopy in Diagnosis

2020 ◽  
Author(s):  
Marco Marando ◽  
Adriana Tamburello ◽  
Pietro Gianella
Keyword(s):  
Low Dose ◽  
False Negative ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Oral Swab ◽  
Negative Results ◽  
False Negative Results ◽  
Polymerase Chain ◽  
Pcr Assays

On 11 March 2020, the WHO declared COVID-19 a pandemic and global health emergency. We describe the clinical features and role of ultra-low-dose chest computed tomography (CT) and bronchoscopy in the diagnosis of coronavirus disease (COVID-19). In our patient, who was highly suggestive clinically and radiologically for COVID-19, we had two false-negative results for nasopharyngeal and oral swab reverse-transcriptase polymerase chain reaction (RT-PCR) assays for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Eventually, we confirmed the diagnosis using bronchoscopy and bronchoalveolar lavage (BAL).

scholarly journals Improving of the Nested PCR for Detection of Bovine Leukemia Virus

2021 ◽  
Vol 83 (3) ◽  
pp. 56-65
Author(s):  
L.M. Ishchenko ◽  
◽  
V.V. Nedosekov ◽  
V.D. Ishchenko ◽  
O.Yu. Kepple ◽  
...  
Keyword(s):  
Internal Control ◽  
Nested Pcr ◽  
Bovine Leukemia Virus ◽  
Leukemia Virus ◽  
False Negative ◽  
Envelope Gene ◽  
Rt Pcr ◽  
Second Stage ◽  
Negative Results ◽  
False Negative Results

Enzootic bovine leukosis caused by a bovine leukemia virus has a significant economic impact and is reported in World Organization for Animal Health(OIE). Aim. The purpose of our work was to improve the nested polymerase chain reaction (PCR) recommended by the OIE conducting it second-stage in real-time (RT) PCR. Such modification does not require the stage of gel electrophoresis and consequently reduces contamination risks and prevents false positive results. Methods. Primers that are recommended by the Manual of Diagnostic Tests and Vaccines for Terrestrial Animals (OIE) were used for the first amplification stage. For the second stage of the proposed modification of nested PCR, the primers and probe were designed based on the alignment of the sequences envelope gene of different isolates of bovine leukemia virus including Ukrainian isolates. Amplification of the internal control was carried out for the second stage to prevent false negative results. Results. Comparative studies of 48 blood samples for bovine leukemia virus identification by a proposed nested RT-PCR, nested PCR recommended by the protocol of the OIE, and RT-PCR were conducted. The sample panel included both positive and negative samples. A 100% match of the results of the bovine leukemia virus presence in nested PCR proposed by the OIE and in our proposed nested RT-PCR was obtained. Comparative analysis of results that were obtained using the RT-PCR and the proposed nested RT-PCR showed that false-negative results in 5 samples and 3 doubtful results that require retesting were obtained by use of RT-PCR. The interpretation of the results using nested RT-PCR is more efficient than RT-PCR since the cycle threshold value of positive samples obtained using RT-PCR was in the range of 24–40 cycles, whereas in the case of nested RT-PCR using, the value of Ct was in the range of 4–20 cycles. Conclusions. Proposed nested PCR modification includes the combination of the OIE recommendation about nested PCR and the reduction of the risk of contamination by conducting the second stage in RT-PCR. Results of approbation of proposed nested RT-PCR give a reason to recommend it for the identification of bovine leukemia virus.

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