key: cord-0961667-olgm4k6p authors: Parry, Arshed Hussain; Wani, Abdul Haseeb; Yaseen, Mudasira; Jehangir, Majid; Choh, Naseer Ahmad; Dar, Khurshid Ahmad title: Spectrum of chest computed tomographic (CT) findings in coronavirus disease-19 (COVID-19) patients in India date: 2020-06-24 journal: Eur J Radiol DOI: 10.1016/j.ejrad.2020.109147 sha: 4f04b0040ff122e148b3768d9f37b053e7ff9362 doc_id: 961667 cord_uid: olgm4k6p PURPOSE: To report the spectrum of chest computed tomographic (CT) imaging findings in coronavirus disease-19 (COVID-19) infected Indian patients. METHODS: This was a prospective descriptive study comprising 147 consecutive reverse transcriptase polymerase chain reaction (RT-PCR) positive patients who underwent CT chest. Prevalence, distribution, extent and type of abnormal lung findings were recorded. RESULTS: Among the total study cohort of 147 patients, 104 (70.7%) were males and 43 (29.3%) were females with mean age of 40.9 ± 17.2 years (range 24-71 years). We observed lung parenchymal abnormalities in 51 (34.7%) cases whereas 96 (65.3%) RT-PCR positive cases had a normal chest CT. Only 12.2% of the patients were dyspneic, 6.1% had desaturation, 7.4% had increased respiratory rate and 10.9% had comorbidities. Among the patients with abnormal CT findings bilateral 39/51 (76.5%), multilobar (88.2%) lung involvement with a predominant peripheral and posterior distribution was commonly observed. With regards to the type of opacity, ground glass opacity (GGO) was the dominant abnormality found in all 51 (100%) cases. Pure GGO was observed in 15 (29.4%), GGO with crazy paving pattern was seen in 15 (29.4%) and GGO mixed with consolidation was noted in 21(41.2%). Peri-lesional or intralesional segmental or subsegmental pulmonary vessel enlargement was observed in 36 (70.6%) cases. CONCLUSION: In this study population predominantly with mild symptoms and few comorbidities, two-thirds of RT-PCR positive patients had a normal chest CT; whereas the remaining patients showed typical findings of predominant GGOs with a bilateral distribution and peripheral predominance. Coronavirus disease 2019 , caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread unabated across the globe after its emergence in Wuhan, China at the end of 2019. According to the World Health Organisation (WHO) situation report-137 more than 6.5 million people have confirmed positive globally with 387 177 deaths as of June 05, 2020 (1). SARS-CoV-2 is an enveloped single-stranded RNA virus (2, 3) . The clinical presentation ranges from a symptomatic, mildly symptomatic cases to severely ill (4, 5) . Imaging findings of COVID-19 closely resemble other viral pneumonias and mainly include ground glass opacities (GGO) with a peripheral and basal predominance as the initial manifestation of the disease (6) . There is a gradual transformation of GGOs into consolidations during the intermediate stage of the disease. The CT findings peak around 9-13 days after symptom onset. Clinical recovery is associated with a gradual resorption of pulmonary opacities with development of subpleural J o u r n a l P r e -p r o o f lines, reticulations, fibrous stripes and perilobular opacities, usually apparent after the second week. In some patients the clinical course is complicated by acute respiratory distress syndrome (ARDS) or pulmonary embolism, the main causes of death (6) . Pleural effusion, pericardial effusion, mediastinal lymphadenopathy are seen in patients with severe disease (7, 8) . The aim of the present study was to report the chest CT imaging manifestations of SARS-CoV-2 infection in Kashmir, India. This was a prospective observational study from 17, March 2020 to 16, April 2020, conducted in the chest disease hospital of Kashmir, India, which was a designated COVID-19 Care Centre (CCC) with separate inpatient, intensive care unit (ICU) and quarantine facilities. Requirement of informed patient consent was waived off by the Institutional Ethical Committee (IEC). 147 consecutive symptomatic patients referred to our CCC from various districts were subjected to chest CT after obtaining nasopharyngeal swab for RT-PCR. Clinical characteristics including age, gender, history of exposure, symptoms, blood tests including complete blood count (CBC) and C-reactive protein (CRP) and outcome data during the hospital stay were collected and analyzed. Patients with severe illness, defined by the WHO interim guidelines for clinical management of COVID-19 as (1) respiratory rate ≥ 30 breaths/min, or (2) oxygen saturation (SpO2) ≤ 90%, or (3) respiratory failure needing mechanical ventilation, or (4) ARDS, or (5) shock (9) were admitted to intensive care unit (ICU). Patients with symptoms but no signs of respiratory failure were admitted in routine ward. Asymptomatic cases did not undergo chest CT and were observed in the quarantine facility of the CCC. Chest CT was performed on an average 5.8 days (range 3-9 days) after symptom onset. Noncontrast chest CT was performed using a 16-row multi-detector CT unit (SOMATOM Emotion 16 scanner; Siemens, Erlangen, Germany) with the following parameters: tube voltage 100-120 kVp, tube current 90-130mAs, collimation of 16×0.6 and a pitch of 1.5. The CT images were acquired in a single inspiratory breath-hold. Images were reconstructed using increment of 0.7mm into 1mm thick slices. The images were viewed in both lung window settings (width 1200-1500 HU; centering -500 to -600HU) and mediastinal window (width 300-400HU; centering 40HU). Decontamination of the CT suite was performed using 70% ethanol or 0.1% sodium hypochlorite. After each CT examination, passive air exchange was allowed for 60 minutes. J o u r n a l P r e -p r o o f Two radiologists (P.A, WA with 8 and 7 years of experience in radiology, respectively) independently reviewed CT images on an Osirix MD workstation (Apple Mac) (10). In case of any disagreements between the two primary interpreting radiologists, two senior radiologists (J.M and C.N with 18 and 15 years of experience, respectively) adjudicated the final decision. The readers assessed the following features: presence or absence of pulmonary opacities; location; type of opacities and the extent of opacities. The location of lesions was specified with regards to involvement of one lung (right, left) or both the lungs. The number of lobes involved was determined. Zonal distribution of the opacities was classified as central (defined as the inner two-third of the lung tissue) and peripheral (defined as outer one-third of the lung). The distribution of lung abnormalities was also dichotomized into anterior and posterior location (lung tissue anterior to a line drawn midway on axial CT was defined as anterior and the portion behind it was defined as posterior). Lung lesions were categorized using Fleischner society glossary of terms for thoracic imaging (11). GGO (ground glass opacity) was defined as an increase in the density of lung with non-obscuration of bronchial and vascular structures, whereas consolidation was defined as increased density of lung tissue through which vascular and bronchial structures were not visible. Furthermore, the readers also evaluated presence of associated airway, vascular, pleural and mediastinal abnormalities. A semi-quantitative scoring system was used to quantitatively estimate the pulmonary involvement by visually calculating the percentage of the total lung involvement by dividing each lung into 3 zones, followed by averaging the 6 zones to obtain the percentage of the total lung involvement (12) . Among the total study cohort of 147 patients, 104 (70.7%) were males and 43 (29.3%) were females with mean age of 40.9±17.2 years (range 24-71 years). In 141 (95.9%) cases a history of close contact with an infected patient or a history of travel to a high risk zone within or outside the country was forthcoming. Fever was the commonest symptom seen in 74 (50.3%) followed by fatigue or malaise in 61 (41.4%), cough in 57(38.8%) and sore throat in 41 (27.9%). Only 18 (12.2%) of the patients were dyspneic, 11 (7.4%) had increased respiratory rate and 9 (6.1%) had desaturation. Comorbidities were present in 16 (10.9%) patients. Lymphopenia was observed in 50 (34%) patients whereas lymphocytosis was seen in 14 (9.5%). C-reactive protein was elevated in 77 (52.4%) patients. Patient demographics, clinical features and laboratory investigations are summarized in Table 1 . There was almost a perfect agreement (Cohen's Kappa of 0.83) in reading CT images between the two primary radiologists. The result of chest CT along with the clinical course of study cohort is depicted in Figure 1 . Lung parenchymal abnormalities were observed in 51 (34.7%) cases, whereas 96 (65.3%) RT-PCR positive cases had a normal chest CT. Among the patients with abnormal CT findings, bilateral lung involvement was the commonest, observed in 39/51 (76.5%). Multiple lobe involvement was seen more frequently. 24 (47.1%) had involvement of all the 5 lobes whereas two lobe and single lobe involvement was seen in 6 (11.8%) each. In terms of axial distribution, Table 2 . With regards to the type of opacity, GGO was the dominant abnormality, found in all 51 (100%) cases. Pure GGO was observed in 15 (29.4%), GGO with interlobular septal thickening and intralobular lines, producing crazy paving pattern was seen in 15 (29.4%) and GGO mixed with consolidation was noted in 21(41.2%) (Figure 2) (Figure 3) . None of the patients showed pure consolidation. Reticulations were seen in 15 (29.4%) (Figure 4) . A small number of cases showed subpleural curvilinear lines (17.6%) (Figure 4) , air bronchogram sign (23.5%) and atoll or reverse halo sign (17.6 %) (Figure 3) . Bronchial wall thickening was observed in 6 (11.9%) J o u r n a l P r e -p r o o f and bronchodilatation was seen in 3 (5.9%). We observed peri-lesional or intralesional segmental or subsegmental vessel enlargement in 36 (70.6%) cases ( Figure 5) . None of the patients showed halo sign or cavitation. None of the patients showed pleural effusion, pericardial effusion or mediastinal lymphadenopathy. A higher percentage of diseased lung was observed in patients with severe disease requiring ICU admission (29.6±12.3%) (mean±SD) than in-ward patients with a mild form of disease (10.2±6.6%) (mean±SD). Of the 51 CT positive cases, 6 (11.7%) were admitted in ICU. Two of them demised (one had underlying diabetes and one had chronic liver disease). Only one patient among the negative CT group developed respiratory worsening 9 days after symptom onset and required ICU admission. However, the patient survived. Lung parenchymal abnormalities are summarized in Table 3 . Chest CT manifestations of COVID-19 pneumonia have been widely reported. It has been observed that asymptomatic patients can have a positive chest CT. The converse has also been reported, where symptomatic patients had a negative CT especially during the early phase of the illness (13) . To the best of our knowledge no imaging data of Indian patients is available and majority of the data available have come mostly from China and Europe. A comparison with some severely hit European countries reveals a low case fatality rate (CFR) in Indian patients In an environmentally homogenous cohort (Diamond Princess Cruise ship), Inui S et.al (13) reported a normal chest CT in 21% of symptomatic COVID-19 cases with cough (20%), fever (11%) and dyspnea (3%). They further observed that nearly half (54%) of the asymptomatic J o u r n a l P r e -p r o o f cases had an abnormal CT. In contrast, nearly two-third of the cases in our study with varying severity of symptoms had a normal CT. Ai T et.al (19) reported CT findings in 888 (88.7%) among the total study population of 1014 COVID-19 patients. They further observed that 3% RT-PCR positive cases with clinical symptoms had a normal CT scan. Third, it may be a consequence of relatively young population in our study with mean age of 40.9 years. However, a comparison between various reported data reveals that many studies J o u r n a l P r e -p r o o f which have reported a high CT positivity for COVID-19 had almost a similar age group (<50 years) (20) . However, some studies had clearly an older study population (>50 years) (12, 17) . Alternatively, it may be reflective of a less severe form of the disease in our population which is tentatively indicated by low CFR in our population so far. The less severity of the disease may in turn result from a less virulent strain of virus or a robust immune status of the population. However, both these presumptive explanations must be viewed with caution and are subject to confirmation by appropriate studies. One may also argue that some patients with an initial negative CT may have developed lung changes subsequently during the course of illness. The lack of follow-up imaging precludes us from conclusively refuting this possibility. However, the percentage of patients showing respiratory worsening during the hospital stay from the negative CT group may at least indirectly indicate the proportion of patients developing significant lung changes during the hospital stay. Among the patients with a negative initial CT, only one patient presented respiratory worsening during the hospital stay. Bernheim et.al (22) reported 56% patients imaged within the first 2 days of symptom onset with a negative CT. But only 9% of patients imaged 3-5 days after symptom onset had a normal CT. This number further reduced to 4% when the imaging was performed 6-12 days after symptom onset. We imaged patients after a mean of 5.8 days (range 3-9 days) after the symptom onset. 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