 Hello everyone, I'm Dr. Shreya Gurd, junior resident from Fritschland Institute of Medical Sciences. I will be presenting on the topic, Rule of HRCT Test in Diagnosis and Management of COVID-19 Emolia. The purpose of my study was to identify types of distribution and patterns of involvement on HRCT tests in patients with COVID-19 Emolia. To formulate a HRCT-based severity score and to obtain a cut-off value to radiologically identify clinically mild and severe cases and correlate CT severity score values with anthropological and clinical parameters for evaluation of diagnostic accuracy. This was a retrospective cross-sectional study in which five hundred and two patients who were positive for COVID-19 and were admitted in our hospital over a period of 10 months were evaluated. The patients were classified as severe or mild on admission based on the clinical parameters. Pathological parameters were sent for each patient on day three of their admission. Neutrophil lymphocyte ratio was calculated and D-dimer and ESR values were noted. CT scan was done for each patient on day five of their onset of symptoms using 16-drow MD CT scanner. Each CT scan was evaluated for distribution and patterns of involvement and the data acquired was then analyzed using SPSS version 27. The CT severity score was assigned for each low based on the percentage of involvement. So when there was no involvement, the score was given as zero. For up to 10% of involvement, score was given as one. For 11 to 20% of involvement, score was given as two. For 21 to 30% of involvement, the score was given as three. For 31 to 50% of involvement, the score was given as five. And for more than 51% of involvement, the score was given as five. And for accumulative score, the score of each low was added. Moving on to results, out of 502 patients, 77% presented with mild symptoms. Out of these, males were more as compared to females and around 28% of males showed clinically severe symptoms while only 11% of females presented with clinically severe symptoms. Among the HICT thorac studies, 75% of scans were abnormal while chest x-ray could detect only 40% of scans. In rest of the scans, chest x-ray was given as normal. So the most common pattern of involvement was peripheral distribution, and this was followed by central distribution or mixed distribution. In 94% of cases, peripheral distribution was given. Predominantly six types of patterns of involvement were seen on HRCT. So the most common type was ground glass obesity. This was followed by crazy paving, which was further followed by interlobular septal thickening, consolidations, subdural bands, traction bronchitis, and vascular dilatation. The left lower loop was most commonly involved in our study, and this was followed by the right lower loop. Rest of the loops were less commonly involved. When ROC analysis was applied to HRCT severity score against their clinical staging, a threshold cutoff value of 8 was found to be statistically significant, and the parameters achieved with this cutoff value were 100% sensitivity, 95% specificity, 85% positive predictive value, and 100% negative predictive value with an overall diagnostic accuracy of 96.2%. As we can see from this tabular distribution, the total number of clinically severe cases were 133, and out of those, 114 cases had a score of more than 8. The total number of clinically mild cases were 369, and all of those had a score of less than 8. HRCT severity score was also found to be positively correlated with D-Dimer, ESR, and Neutrophilile Infrasight ratio values, and the strongest correlation was found to be D-Dimer values. Moving on to figures, the first set of figures showed different patterns of involvement which were seen in COVID-19. So as we can see, the first figure shows consolidation, the second figure shows crazy paving, the third figure shows groundless opacities, the next figure shows subplural bands, the next figure shows tractional bronchitis, and the last figure shows vascular dilatation. These were the six most common patterns of involvement, and also we can see that the most common distribution was peripheral. The next set of figures shows how HRCT severity score was assigned for each low. As we can see from the first set of figures that when the cumulative score was around 10%, the score was given as 1. The next set of figures shows that the cumulative involvement was around 11-20%, and the score was given as 2. The next set of figures shows that the cumulative involvement was around 21-30%, and the score was given as 3. The next set of figures shows that the cumulative involvement was around 31-40%, and the score was given as 4. And the last set shows that the involvement was more than 50%, and the hence score was given as 5. In our study, the patients who were cancelled were those who could be mobilized to our CT room, and thus the patients who were mechanically ventilated or could not be mobilized for other reasons, but excluded, and hence this was the limitation of our study. Thus we concluded that due to constraints of our study, most of the patients were clinically mild. On imaging, HRCT thorac showed peripheral distribution with ground-glass opacities and crazy paving as most common findings. The most common sites of involvement were left low-low, followed the right low-low. The ROC curve showed that the cut-off value for CT severity score which corresponded to the clinical severity was 8, and thus the score below 8 signified mild cases, and the score above 8 signified severe cases. Amongst the pathological parameters, strongest correlation was seen with D-dimer, and hence the CT score was strongly correlated with D-dimer values. These were my references. Thank you.