 Good morning, everyone. My topic for the study is high resolution computer tomography findings in COVID-19 diagnosed and suspected cases. The aim of the study is to study the HRCT manifestations in the evaluation of COVID-19 suspected and diagnosed patients and study its correlation with respect to CT severity scoring with symptomatology, comorbidities, lab parameters and oxygen requirement in the study group. During COVID-19 pandemic, over 770 million confirmed cases of SARS COVID-2 were reported by the World Health Organization, including over 6.9 million deaths. Infected infection by COVID-19 virus can result in a wide range of clinical outcomes from being asymptomatic to severe life threatening course or death. Symptoms due to COVID-19 infections can include fever, dry cough, breathlessness, anosmia and malaise, which are non-specific symptoms. Common laboratory findings include decreased leopocyte count, increased CRP levels and increased ferretin levels and increased de-diamol levels in some patients. HRCT is an important and irreplaceable method for early detection of COVID-19 associated lung abnormalities when clinical features are non-specific spars or when patient is asymptomatic. It plays an important role in screening the COVID-19 suspected patients' diagnosis of COVID-19 infections in disease progression, in detection of complications and for follow-up of a discharge to look for changes of fibrosis. The most common CT finding include bilateral patchy ground glass opacities involving multiple lobes of the lung. These opacities are more likely to show peripheral distribution than central distribution and are more patchier than oval. Other CT findings with pure ground glass opacities can also include GGOs with interlobal septal thrifting, GGOs with consolidation or pure consolidation. Plural effusion, lymphadenopathy, pericardial effusion, cavitations and pneumothorex are some of the atypical but possible findings and can be seen in COVID-19 infections. Now coming to the methods, this was a descriptive study conducted between July 2020 and July 2022 at Dr. D. Y. Patterson Medical College, Hospital and Research Centre Pune after taking necessary approval by the Institutional Scientific and Ethics Committee. 500 patients meeting the inclusion criteria for the study were included in the study after taking a written informed concept from all the patients. Coming to the results, a total of 500 study participants were included out of 27% which is 133 patients were categorized, that is mild on the basis of CT severity score, 51% which is 257 patients were categorized as moderate and 78 participants were categorized as severe. 32 patients, which is 6.4% of the patients who were suspected for having COVID-19 infections and being diagnosed as COVID-19 positive on RTPCI tests showed normal HR CT scans. Our study group included 311 male and 189 females and the proportion of male showing severe disease were more in comparison to female as described here. About 39% of the total female population have either a normal HR CT or being categorized into mild severity in comparison to 29% males having a normal HR CT or being categorized into mild severity on the basis of HR CT score. Now coming to the tables and figures, this table 1 shows the typical features of COVID-19 infection on HR CT scans, which are ground glass opacities, interlobular septal thickening, crazy paving pattern and consolidation. Here we can see that people having severe disease, 100% of those people showed ground glass opacities and septal thickening, crazy paving pattern and consolidation were seen more commonly seen in people having severe disease and less commonly seen in people having mild and moderate disease. In our study group population bilateral involvement of the lung parankyme on HR CT was more common and was seen to affect approximately 84.8% of the total population and unilateral lung involvement was only seen in 6.8% of the total population. It was also shown that there was a lower lobe predominance in early and milder form of the disease with the right lower lobe being the most common lobe being affected followed by the left lower lobe. It was also seen that there was predominantly peripheral distribution of the lung changes on HR CT in our study group. Coming to the table 2 and figure 1, table 2 shows the distribution of atypical findings on HR CT according to the DZ severity groups as per CT severity score and atypical findings were present in 38.5% of the people having severe disease. This is a graphical representation of the same and this figure also shows the main days since the symptom onset and CT severity scoring which was the highest for the severely disease people which was 7.3. Now these atypical symptoms include pleura fusion which is the most common atypical findings finding and other atypical findings are pericardial effusion bronchitis, emphysematis pulmonary cysts and however no patients develop pneumothorax in the control group and the mild group at four patients in moderate group and only three patients in severe group develop pneumothorax. Only one patient in the moderate group had cavitations. However, there was no statistically significant association between CT severity scores and bronchitis, emphysematis pulmonary cysts, cavity atypical relations, pericardial effusion and barotroma associated changes like pneumothorax and surgical emphysema. This table 3 shows distribution of the symptoms like anosmia, sore throat and chest pain in the disease categories on the basis of CT severity score. The most common symptom seen was cough which was seen in 65.2% of the patients chosen followed by fever whereas test pain was seen only in 78% of the population. The association between these symptoms and disease severity groups as per CT severity scoring statistically significant. Table 4 shows the distribution of asymptomatic patients suspected of COVID-19 disease on the basis of CT severity score in our study population about 14.2% that is 72 people were asymptomatic of the total patients having normal CT scan and being categorized in the negative group about 46.9% were asymptomatic. Of the total population having mild CT severity score 28.6 patients were asymptomatic and in the population having moderate score 6.6 patients were asymptomatic only one patient having severe CT score was asymptomatic. Now, this is a table 5 which shows the distribution of patients with hypertension, diabetes, malitis or asthma in DG severity groups classified according to CT severity score. Now, amongst the severely diseased people, 38.5 people had hypertension, 24.4 people had diabetes, malitis and none had asthma. So, the correlation of hypertension with the disease was statistically significant. Table 6 shows the distribution of normal or abnormal lymphocyte count CRP and serum ferritin and also the D-dimer levels in the disease severity groups classified according to the CT severity score. So, amongst the diseased people of course the TLCs were decreased the D-dimer and serum ferritin levels and the CRP levels were raised however it did not show any statistical significance as we can see from the P values here. Now, table 7 showed the oxygen requirement in disease severity groups classified according to the CT severity score. So, amongst the severely diseased people 64.1% of the population needed oxygen amongst the moderately diseased patients 39.3% of the population required oxygen amongst the mildly diseased people 6.8% of the population required oxygen. Now, coming to the discussion part, COVID-19 infection has become a pandemic with significant impacts upon the healthcare delivery system and causing increasing morbidity and mortality. Now, World Health Organization advised to use test radiographs in HRCT thorax as part of the workup for diagnosis of COVID-19 infection in cases of unavailability of RT-PCR tests delayed the results of the RT-PCR tests clinical suspicion of COVID-19 in spite initial negative RT-PCR test result. Our study had been performed with intention to aid the clinicians in taking better decisions for making the accurate diagnosis of COVID-19 disease assessing the disease severity and also being useful in providing appropriate supportive care and treatment for the affected populations. We use the visual assessment of each of the five lobes which is also called the low bar method. Now, based on this method, COVID severity score was considered as mild with CT severity score between 1 and 7 moderate with CT severity score between 8 and 15 and severe with the score being between 16 and 25. So, in our study, younger population had mild CT severity score by older age groups had moderate and severe CT scores. These findings were similar to the study done by SAID et al in a study conducted on 902 patients and another study performed by Fargherli et al on a study conducted on 574 patients. Severe form of COVID-19 was commonly observed in male population. Similar observations were made in previously conducted studies such as those conducted by SAID et al and Mozavik et al who had observed strong positive correlation between male sex and increment in the CT severity score. The study found that the bilateral Rung-Parenchyma involvement was more common in male CT severity and earlier disease scores, the preference for peripheral lung involvement, lower lobe involvement was more prevalent with the right lower lobe being more involved. Now, ground class opacities interlobular septal thickening, crazy paving pattern and consolidation were the most common chest CT findings amongst the COVID-19 patients. These findings are considered as the typical manifestations of COVID-19. Similar findings were also seen in the previous studies conducted by the following authors. They had also observed that GGOs by itself or in conjunction with consolidation were the most common findings on HRCT in COVID-19 patients followed by interlobular septal thickening, crazy paving pattern and subdural lines. Atypical features of COVID-19 disease on HRCT were found in 24% of the total population, more common in patients with moderate and severe severity scores. Tural effusion was the most common atypical findings followed by midiastinal lymphadenopathy. This difference was found to be statistically significant. Similar to a study considered by Lee et al. that found atypical features more commonly in severe and critically diseased patients. Bronchial clases and other features like infisomatous pulmonary cysts and cavitations did not show any significant correlation with the increasing CT severity scores. A study conducted by Magality et al. found a higher barotroma prevalence in mechanically ventilated patients. In our studies, spontaneous pneumothorax with pneumomedia stenum and subcutaneous emphysema were observed in seven patients but not statistically significant. These features can be attributed to heterogenic induced barotroma as observed in our previously studied literature. Our study also found that the earlier a patient presents with their first symptoms, the milder the lung involvement is on HRCT. Patients with mild CT severity scores had the lowest mean number of days since the first symptom followed by moderate and severe scores. Common symptoms included cough, fever, sore throat, breathlessness, enosmia and chest pain. The association between these symptoms and disease severity was significant. Asymptomatic patients with history of contact with an infected patients were found to have a milder lung involvement based on the CT features. Now, however, in these patients CT is a crucial method for screening and detecting these patients as they can act as a covert transmitter or progress to a severe disease if not adequately evaluated and treated. Now, similar observations were also seen in the previously conducted studies by the following authors. Our study also found that the had hypertension was the most common comorbidity in COVID-19 patients followed by diabetes, malitis and asthma. Severe CT severity groups had the highest prevalence of hypertension with positive CT findings, more prominent in comorbid patients. Previously done studies showed that HRCT helped assess oxygen support requirements in disease populations. In our study, our study supports these previous studies done by Akshay et al. and emphasizes the importance of CT severity scores in determining oxygen support requirements in COVID-19 patients. Our study has also found a significant correlation between elevated CRP levels and CT severity scores with lymphopenia in 32.5% of the population. However, no statistical significance was found between lymphopenia and CT severity scores, unlike the previous studies conducted by Psyde et al. and Neelma et al. No statistically significant difference was observed between elevated serum ferritin levels and CT severity scores too. The study's smaller sample size may explain the lack of the statistical significance between lymphopenia elevated ferritin levels and CT severity scores. Further research with larger samples could help establish a relationship between these factors. Now, previously done studies also found that 30% of the COVID-19 pneumonia patients had pulmonary thromboembolism on CT pulmonary angiography compared to 1% in non-COVID patients. In our study, only 11 patients under one CTPA due to breathlessness and elevated D-diamond levels, 8 patients had pulmonary thromboembolism with D-diamond levels and CRP levels found raised in all of these 8 patients. No statistical significance, however, was found between pulmonary thromboembolism incidents and CT severity scores. Now, to conclude my study, I would like to say that COVID-19 disease has had a significant negative impact on the healthcare system across the world. Now, HRCT imaging plays an important role in accessing disease severity and progression. It also plays an important role in triage to assess oxygen requirement and help get clinicians and overcoming dilemma to administer adequate and necessary treatment. CT severity scoring can help to stratify on a certain risks and prognosis involved for a patient and is also useful to predict short-term outcome of these patients. Due to its ability to provide results rapidly in contrast to the RT-PCR tests, HRCT examination of thorax is also useful as to evaluate possibility of COVID-19 infection. In our study, we have been able to collect information of typical and atypical findings on HRCT in COVID-19 disease and presence of various features with respect to different phases of the disease progression. In our study, the extent of CT damages per CT severity score correlates significantly with the age, gender of the patient, symptomatology, alter laboratory parameters and associated comorbidities in a patient. It helps as a tool to evaluate requirement for oxygen support in suitable candidates in assessing the involved risks of iotrogenic barotoma due to mechanical ventilation and evaluating features of COVID-19 sequence. Few limitations of our study include the timeline of changes in the hematological parameters in relation to the changes in CT scan with progression, regression of the disease severity was not studied and also the study being a single center study. There was unavailability of lab parameters and test radiographs in some of our patients which can likely be attributed to the fact that the proportion of a study group were taking treatment on outpatient basis. Factors such as lifestyle and other risk factors which can affect COVID-19 severity should have been considered in more detail, so further investigations and researches are needed. Our study supports the use of HRCT in patients with COVID-19 infection which could be used as a rapid and effective gatekeeper to rule out patients with a low likelihood of disease. Now coming to the case gallery, I would like to present a few cases. The first case in figure three is a 44 year old female diagnosed is a RT-PCR diagnosed case of COVID-19 with a severity score of 4 by 25 which is mild severity and here we can see that on coronal and exel sections the ground glass opaque cities are seen. The second case seen in figure four is a 28 year old female who tested positive for COVID-19 and has a CT severity score of 9 by 25 which comes under the moderate category. And here we can see the ground glass opaque cities on coronal sections and here on exel sections. The third case here is a 41 year old male tested COVID positive with a CT severity score given 25 by 25. And here we can see that the both lungs, all lobes of actually both lungs show ground glass opaque cities. Here are the coronal and exel sections. Some also show interrobial septal thickening and crazy paving pattern. In this case in figure six, we can see that a 50 year old COVID positive patient is given a CT severity score of 20 by 25 and it shows bilateral rural effusion which is seen here. Now coming to the last case which I will be showing here, figure seven represents a 46 year old male which was diagnosed as COVID positive with a CT severity score of 20 by 25. Now this patient had a history of mechanical ventilation and showed signs of pneumomaniastinum and surgical emphysema due to barotoma. And here we can see the emphysema changes in the lung window and the soft tissue window seen here on exel sections. Thank you.