Images of Chest Computer Tomography (CT) and Radiation (X-ray) Demonstrating Clinical Manifestations of COVID-19: Review Article

Abstract

Apart from reverse-transcription polymerase chain reaction (RT-PCR) testing, chest radiographs (CXR) and computed tomography (CT) scans were employed as crucial diagnostic methods for detecting the 2019 new coronavirus disease (COVID-19). Our objective is to examine three notable COVID-19 instances from patients across the globe, along with their CXR and CT data. The evaluation of the imaging characteristics of the reported instances was the primary objective of a methodical examination of the literature. We located more than several articles that had been published between 2020 and 2023. After the papers were examined, three major cases were chosen, including a COVID-19 assessment of imaging features (chest X-ray and CT scan). Corona viral diseases (COVID-19) pose a significant risk to healthcare facilities, especially when the patient has additional medical issues. It is challenging to understand the various chest radiography results because of the use of specialized and ambiguous terminology such as “airspace disease”, “pneumonia”, “infiltrates”, “patchy opacities”, and “hazy opacities”. The current investigation considered peer-reviewed case reports with Images features. Study designs, including reporting cases, were considered for imaging feature analysis.

1. Introduction

Towards the end of the year 2019, the world witnessed an outbreak of a novel infectious disease whose origin was traced back to the Hubei province of China in a city called Wuhan. The present outbreak is currently referred to as COVID-19 [1,2,3,4].

The coronavirus illness is caused by the severe acute pulmonary condition coronavirus 2 (SARS-CoV-2), also known as the 2019-nCoV. It is the seventh coronavirus [5,6,7,8,9,10,11,12,13]. The disorder causes a health condition that may sometimes give rise to severe respiratory difficulties, which need to be managed and supervised in the intensive care units (ICU) [14,15,16,17,18,19,20,21,22]. COVID-19 causes neurologic and enteric diseases, particularly in patients with a compromised immune system, such as children, pregnant women, and the elderly. Moreover, the disease can be life-threatening [23,24,25,26]. COVID-19 was initially recognized in 1960 as a factor responsible for the ordinary cold [23,27,28,29,30,31,32].

Previously, other beta-coronaviruses had triggered epidemics in Asia over the last twenty years. These epidemics were specifically between 2002 and 2003 in China in the case of SARS-CoV [33,34,35,36], and later in Saudi Arabia between 2012 and 2013, known as the MERS-CoV or the Middle East Respiratory Syndrome [37,38,39,40,41]. Significant variations and similarities exist in the clinical characteristics, epidemiology, and management options employed for SARS, MERS, and COVID, as expected [14,16,17,39,42,43,44,45].

These viruses are characterized by having positive-strand RNA, which is recovered from bats and have a similar structure to those found in humans. This suggests that bats are the original host and reservoir for these viruses [46,47,48,49].

Although SARS, MERS, and COVID-19 have some clinical symptoms, there are significant differences between them [42,44,50,51] ever since the initial accounts. Hence, it is necessary to do thorough characterizations that consider the clinical, laboratory, and imaging aspects.

Early detection is essential for COVID-19 control due to its rapid spread. SARS-CoV-2 nucleic acid, antibodies to N or S protein, simple chest X-rays, and high-resolution CT with X-rays are diagnosis alternatives. When molecular detection was overwhelmed, conventional chest X-rays (CXR) and high-resolution CT were utilized to quickly identify patients and assess disease severity. The CXR results after two days of RT-PCR showed that better heat maps of influential regions improved deep learning prediction scores via machine learning [52]. CT is used for immediate diagnosis in asymptomatic patients with negative RT-PCR test results because it provides better disease findings and long-term follow-up with 29% higher sensitivity than chest radiography [53]. Patients with high clinical suspicion of COVID-19 underwent CT scans and repeated swabs [54].

The characteristic computed tomography (CT) findings for COVID-19 pneumonia included aggregation and contralateral ground-glass opacity (GGOs) that were distributed equally across the back and outer areas of the lungs [4,5,6,7,8,9,10,11]. The early radiological investigations consistently corroborate these conclusions [55,56,57]. Since the COVID-19 pandemic, research has examined the association between CT results and patient outcomes, and chest CT’s predictive usefulness at COVID-19 diagnosis has grown. Many studies have linked ICU patients with poor prognoses to CT findings such as scattered bilateral distribution of lesions, a higher number of involved lobes, diffuse GGO and consolidations, absence of mixed and reticular patterns, crazy paving, bronchus distortion, etc. Pathophysiology, radiological-pathological markers, quantitative CT metrics, and lung function in COVID-19 patients have also been studied. CT findings are difficult to standardize as a predictor because each study describes them differently [12]. Other semi-quantitative studies have assessed baseline chest CT’s prognostic significance by awarding scores based on parenchyma involvement. Recently, chest CT image analysis employing several AI models has classified patient risk, but its clinical relevance as a predictive tool must be investigated. The longitudinal alterations in chest CT scans of COVID-19 patients have been studied throughout the epidemic. Few studies have examined these alterations using repeated clinical measures and quantitative CT ratings.

Despite the relatively short time since the emergence of COVID-19, numerous studies have been published in esteemed worldwide medical and scientific journals by researchers from China and over 203 other countries. The published articles consist of case reports that encompass both travel-related and non-travel-related situations [19,58,59,60,61,62,63,64,65,66,67].

Many of them have started to give answers to the imaging results. However, as far as the authors are aware, there have been no individual case reports that bring together the knowledge from different investigations. The objective of this study is to examine three main cases in order to present a current and comprehensive analysis of the radiographic representation of individuals with COVID-19. This was achieved by utilizing chest X-ray (CXR) and computed tomography (CT) findings from diverse instances around the world. The presentation encompasses clinical symptoms and findings, as well as CT and radiographic follow-up imaging [68,69,70,71,72,73,74,75,76].

This review is unique in examining three global COVID-19 cases and their CXR and CT data. A methodical literature review focused on the imaging characteristics of reported events. More than several 2020–2023 items were found.

2. Methods

Peer-reviewed case reports and studies that reported instances with picture features were taken into consideration for the current investigation. Study designs, including reporting cases, were taken into consideration in order to be qualified for analyzing imaging features. Only articles written between 2020 and 2023 were allowed, and the language of the article was limited to English. In addition, only papers were considered, whereas assessments, words, and any other publications lacking preliminary data were eliminated. The current study utilized data from the Web of Science, Scopus, and Medline/PubMed databases. The search terms used were “new coronavirus”, “new coronavirus the year 2019”, “2019 nCoV”, “COVID-19”, “Wuhan, China coronavirus”, “Wuhan, China respiratory infections”, and “the SARS-CoV-2”. By the year 2022, all the research had been completed, and a wide range of independent researchers had evaluated the findings.

In the beginning, the search results were selected based on the title and abstract. The full text of the pertinent papers considered pertinent in the current investigation was then retrieved. Duplicate data reports were not included and were counted as a single case. For the study, case reports were used, and their conclusions were compiled. Data extraction methods that take into account the type of publication, publishing year, date of publication, country of publication, institution of publication, and the number of notified instances were researched. Additionally, data on age and sex, outcomes such as death, complications like acute respiratory distress syndrome (ARDS), imaging like x-rays of the chest, laboratory results like biochemicals and counts of white blood cells (WBCs), and clinical properties like cough were examined. The set of articles and the extracted records were reviewed, and any discrepancies were resolved in order to prevent repetitions of either the article or the records for the same case.

3. Results and Discussion of the Case Studies

3.1. Case A

Pt history: Between January to 9th February 2020, nine successive COVID-19 sick persons (average age, 54 years; five females and four males) were established via a PCR reaction assay. These cases were reported at the Korea National University Medical Center, Korea National College Bundang Province Medical Center, and Incheon Health Centre [57].

Chest radiographic procedure: A multiple pf of medical imaging detector CT scanner with a minimum of 64 channels (Somatom Force, Somatom Definition, or Somatom Definition AS+, earned from Siemens Healthineers, Erlangen, Germany) was used for all CT analyses.

The scans were acquired using the following parameters: a sharp reconstruction kernel, a reconstruction interval between 1 and 3 mm, and a thickness slice of 1 mm. A scan is performed with automatic exposure management. The tube current ranges from standard (60–120 mAs reference) to low-dose (30 mAs reference), and the tube voltage is set at 120 kVp.

In order to get the CT picture, patients were positioned in a supine posture while taking a deep breath and without the use of any contrast agents. All patients underwent an initial electronic anterior-posterior chest scan at maximum inhalation using a portable chest cavity radiographic device. The devices used were the DRX-Revolution, a portable X-ray machine imaging program by Siemens Healthineers, the FLUOROSPOT Compact FD by Carestream Health, and the Optima XR220 by GE Healthcare.

Parenchymal abnormalities were observed in eight out of the nine sick people, and their initial chest CT images were taken. while it was normal in one of the patients, but, one week later, the follow-up CT scan indicated the existence of parenchymal anomalies. Therefore, one subsequent CT scan with variations and eight initial chest CT scans without variations were examined for COVID-19 pneumonia.

Chest radiographic and CT results: Out of nine sick people, five displayed radiological pathologies. One patient had a severity grade of 2, while two patients had a severity grade of 3. Additionally, one patient had severity grades 4 and 5.

The CT images of the chest showed that both the grade 3 lesion and 2 are consistent with areas of post-inflammatory focused a condition called shown on chest radiography, and visible breast tissue resembling faint ground-glass opacities, respectively. In summary, chest radiographs demonstrated that 33.3% of the subjects exhibited parenchymal abnormalities associated with COVID-19 pneumonia (Figure 1A, Figure 2A and Figure 3A).

Among the three patients, one had a single nodular opacity located in the lower left zone of the lung (Figure 3A,B), while the remaining two patients presented with four and five dispersed opacities in both lungs (Figure 1A and Figure 2A).

Consolidation was responsible for 70% of the opacities in the per-lesion study, whereas the peripheral lungs accounted for 80% and the lower lung zones accounted for 50% of the 10 opacities that were available. Out of a total of seventy-seven patients, nine were found to have lung parenchymal lesions. Among these nine patients, eight exhibited abnormalities in the form of both lungs’ tissue. The median of the affected lobes and lesions in the tissue were two (inter-quartile range, 2–5) and five (inter-quartile range, 2–13), respectively.

The right side of the lower region was the lobe that was most commonly affected, and it was observed in eight cases. The lower lobes and the left upper lobes were the next, with six patients each. The most frequently identified lesion was patchy, accounting for 48% out of the 77 identified cases, and the remaining were confluent, accounting for only 13% of the cases.

The lesions are confluent, nodular, and patchy, with common sizes of 9.8 ± 2.6 cm, 1.3 ± 0.6 cm, and 2.6 ± 1.5 cm, respectively. The more prevalent lesions were confluent to patchy as compared to nodular lesions, while 78% and 67% of the lesions were respectively associated with peripheral and posterior lung.

Irregular to merged areas of damage (patchy to confluent) were least expressed as areas of consolidation (5%), then clear GGO abnormalities (35%) (Figure 2B,C), with a crazy-paving view (10%), and consolidative and mixed GGO were the most expressed (50%) (Figure 1B,C).

The lesions in the shape of confluent were the least commonplace, accounting for 25% of the cases. The elongated shape accounted for 33% of the cases, while the wedge shape accounted for 42%. Around 70% of the lesions had an indistinct boundary, with air-bronchogram detection occurring in about 28 percent of cases. 57% of the nodular lesions in the study exhibited pure ground-glass opacity (GGO) lesions, whereas 11% were mainly solid and 32% were primarily GGO lesions. 75% of all nodular lesions exhibited unclear boundaries, whereas 95% had a round overall shape.

No pleural effusions or tumors with a tree-in-bud look, micronodules, or cavities were observed. The distribution of lesions was primarily concentrated throughout the pleura (35% vs. 80%; p < 0.001) and frequently affected The inferior branches (35% vs. 60%; p = 0.040) in the case of patchy lesions, as shown in Figure 4A, compared to nodular lesions. The nodular lesions tend to appear as pure ground-glass opacity (GGO) lesions more frequently (57% vs. 35%; p = 0.069). The bronchovascular bundles were the primary method of distribution for the majority of the samples (28% vs. 59%; p = 0.006). The text refers to Figure 4B.

Although there are similarities in the CT scan results of MERS, SARS, and COVID-19, COVID-19 seems to have a less severe impact based on radiological observations. Between 78.3% and 82.4% of the patients showed aberrant radiographic findings at the beginning of SARS [78,79]. In MERS, the percentage was 83.6% [48], whereas in COVID-19 instances, it was only about 33%. 45% of Chinese patients with COVID-19 exhibited ground-glass opacity (GGO) lesions on CT scans, lacking consolidation, in a range of 45% to 67% of cases. [55,56], 50 percent of SARS patients [80], and 14 to 40 percent of MERS Chinese patients [81,82].

CT scan findings for COVID-19 pneumonia cases from China and Korea generally exhibited agreement [55,56,57,83]. Moreover, the percentage of chest radiographic anomalies in Chinese COVID-19 patients was 60% [84], compared to 33% in Korean sick people. Based on the radiological findings, in addition to the absence of fatalities from COVID-19 in Korea, it appears that Korean sick people have encountered a less severe progression of the disease compared to those in China.

Notably, a single patient exhibited a reversed halo sign (Figure 5B), and there have been a few other such cases published subsequently [84,85,86]. The reversed circle indication was initially thought to be a distinctive feature of cryptogenic organizing pneumonia [55,56,57,83]. These infectious disorders, such as angioinvasive aspergillosis of the lungs or pneumonia, bacterial jiroveci respiratory infections, paracoccidioidomycosis, and a condition called mu, exhibit this characteristic [87]. This indication may indicate the presence of an organized pneumonia form in individuals with COVID-19 [86].

Case conclusion: In Korea, COVID-19 pneumonia is typically characterized by the presence of ground-glass opacities (GGO) that range from pure GGO to a combination of GGO and consolidative lesions. These abnormalities are observed in both the peripheral and posterior regions of the lungs. Pathologies exhibited a distinctively ambiguous and irregular pattern, appearing as either nodules scattered in patches or merging together. The lesions, which varied in distribution, were primarily found adjacent to the pleura in a scattered pattern. However, nodular lesions were predominantly located beside the Broncho vascular bundles. The majority of the pulmonic lesions appeared indistinct on chest radiography imaging. It is required that radiologists and doctors have a thorough understanding of the COVID-19 CT findings.

3.2. Case B

Pt history: Between the 6th of January 2020, and the 6th of February 2020, an aggregate of 1049 people were alleged to have the novel coronavirus disease. The average age of suspected sick persons was 51 ± 15 years and consisted of 54% female. These reported suspects undertook both laboratory virus nucleic acid tests as well as chest CT imaging [88].

Chest CT and radiographic findings: The interval period between the RT-PCR assays and the paired chest CT examinations ranged from 0 to 7 days, with a median of 1. Positive chest CT results were recorded for 888 out of 1014 patients (88%) at a 95% confidence interval. The highest chest CT results indicated 50% consolidations and 46% ground-glass opacity (Figure 5, Figure 6 and Figure 7). Also, about 90% of the patients exhibited bilateral chest pain in their CT results.

For RT-PCR results, 67% of the cases in the subcategory of negative to positive initially indicated positive chest CT results prior to the initial negative RT-PCR outcomes. Moreover, about 93% of the cases revealed that the first chest CT showed a typical imaging characteristic in agreement with COVID-19 before (or corresponding) to the early positive RT-PCR results, with a time interval that ranged from 0 to 21 days (median = 8 days).

In a similar subcategory of negative to positive RT-PCR results, about 60% of the cases revealed that the first chest CT showed typical imaging characteristics in agreement with COVID-19 before (or corresponding) to the early positive RT-PCR results, with a time interval that ranged from 0 to 27 days (median = 6 days). Furthermore, for RT-PCR results, almost 100% of the patients in this subcategory of negative to positive initially indicated positive chest CT results prior to or within the first six days of the initial positive RT-PCR results.

In addition, 42% of the patients displayed a positive response upon follow-up chest CT scans in advance of the RT-PCR results showing negative. Also, merely 3.5% of the cases disclosed disease progression on the follow-up CT scans when the RT-PCR results turned out to be negative.

Case conclusion: in the diagnosis of COVID-19, chest CT imaging showed great sensitivity. The investigation of the available data recommends that chest CTs be adopted for the screening of COVID-19. This would allow for ample assessment and follow-up, particularly in epidemic situations with a high pre-test likelihood of the virus.

3.3. Case C

Pt history: 21 patients, 13 males and 8 females, with ages that fall within the range 10–74 years. With the exception of one child belonging to a family cluster established to possess COVID-19, all patients were symptomatic [84].

Chest radiographic and CT findings: out of the 5 patients that had CXR along with CT thorax investigations, 2 cases revealed normal CXR results.

Moreover, notwithstanding having CT examinations conducted on the same day displaying ground glass opacities (Figure 8), the remaining 3 CXR results were consolidative. 1 CXR exhibited predominance in the lower zone, while the remaining 2 CXR results did not show predominance in any zone.

In these 3 cases, CXR investigations did not establish the peripheral predominance visible on their corresponding CT examination.

From the onset of the symptoms, CT thorax analyses were accomplished in a median of 3 days (IQR; 1–7 days). Out of the twenty-one recorded patients, two had normal chest CTs. The principal feature was GGO (n = 18, 86%) followed by consolidative opacity (62%; Figure 9).

4 cases had predominantly consolidative changes; another 4 had mixed appearances; and 11 cases had predominantly GGOs. With the exception of one patient who had perihilar ground glass changes, the consolidative and ground glass opacities were peripheral in all patients with lung findings (n = 18). Three of the patients showed upper zone, while eight indicated lower zone predominant changes. Hilar lymph node enlargement, pleural effusions, cavitation, mediastinal and pericardial effusions, and subpleural sparing were not found in any of the patients.

4 out of the 21 patients had a follow-up CT, while 3 had their follow-up CT accomplished within 4 days subsequent to the initial CT. One patient had a follow-up CT 3 days after the first one. A decrease in consolidation was observed in one of the patients (Figure 10).

A normal CT thorax examination of the second patient was observed at the initial presentation, and this continued to be normal with no changes in the lungs. For the third patient, the CT displayed progression of the lung alterations with fresh ground-glass nodules in the other lobes.

The earlier ground-glass opacities became bigger with some peripheral consolidations (Figure 11). For the fourth patient, it was observed that the ground glass opacities witnessed earlier became reduced in the areas of consolidation. Consolidation and ground-glass opacities were most commonly observed in the right lower lobe (76%), left lower lobe (81%), and left upper lobe (also 76%). The lowest contribution was observed in the right middle lobe (48%).

Compare COVID Presentation in CT and CXR and others Viruses

Individuals under suspicion of COVID-19 must promptly ascertain their infection status to provide timely medical intervention, self-quarantine, and notification of close contacts. At present, the official diagnosis of COVID-19 necessitates a laboratory examination (RT-PCR) of samples obtained from the nasal and throat regions. The RT-PCR test necessitates specialized apparatus and has a minimum turnaround time of 24 h to provide a result. The use of chest imaging has proven to be beneficial in the progression of this pulmonary condition. The chest X-ray (CXR) and computed tomography (CT) scan pictures provide a rapid and precise diagnosis of COVID-19. The two most commonly utilized imaging modalities to assess individuals with COVID-19 are chest X-ray (CXR) and computed tomography (CT) scans. These approaches aid clinicians in discerning the impact of COVID-19 on distinct organs at different phases of the disease. They are applied to the chest and lungs due to the fact that respiratory symptoms are recognized as one of the initial indications of COVID-19 [68,70,89,90,91].

4. Conclusions

Integrating chest imaging with deep learning models offers a precise and effective approach to identifying, measuring, and monitoring the progression of the COVID-19 disease. This investigation has identified a favorable result that differentiates COVID-19 patients from other cases of pneumonia and negative cases. The risk of Corona viral diseases (COVID-19) to healthcare facilities is high, especially when the patient has other health issues. It is challenging to understand the various chest radiography results because of the use of specialized and ambiguous terminology for instance “airspace disease”, “pneumonia”, “infiltrates”, “patchy opacities”, and “hazy opacities”.