key: cord-0881986-7fkaj1h8 authors: Ding, Jinli; Liu, Yaou; Fu, Haihong; Gao, Jianbo; Zhao, Xin; Zheng, Junhui; Sun, Wenge; Ma, Xinwu; Feng, Ji; Liang, Pan; Wu, Aiqin; Liu, Jie; Wang, Yun; Geng, Pengfei; Chen, Yong; Li, Hongjun title: Experience on radiological examinations and infection prevention for COVID-19 in radiology department date: 2020-03-31 journal: Radiol Infect Dis DOI: 10.1016/j.jrid.2020.03.006 sha: c75fe1f4c9f38f76925b048dc3a97e532a6e16da doc_id: 881986 cord_uid: 7fkaj1h8 Abstract In December 2019, a cluster of patients with emerging pneumonia of unknown etiology were discovered in Wuhan city, China. Laboratory examination identified a novel coronavirus which was tentatively named as 2019 novel coronavirus (2019-nCoV) by the World Health Organization (WHO) in January 2020. The WHO has more recently formally named the 2019-nCoV as coronavirus Diseases 2019 (COVID-19). Within one month, the novel coronavirus rapidly spread across the whole of China through droplet transmission and contact transmission, and the reported number of confirmed COVID-19 cases demonstrated a rising trend. Radiological examinations, especially computed tomography CT, were confirmed as effective methods for the screening and diagnosis of infected cases. Reports stated that many radiologists and technologists were being infected when examining patients with COVID-19. In order to clarify the imaging features of COVID-19 and reduce the infection risk of medical personnel in radiology departments, we summarized the experience on radiological examinations and infection prevention for COVID-19, aiming to guide virus prevention, diagnosis and control within radiology departments. Since December 2019, a number of patients with pneumonia of unknown etiology have been reported in Wuhan, Hubei province, China [1] [2] . It was reported that most of these patients worked at or lived in the vicinity of the local Huanan Seafood Wholesale Market. Severe acute respiratory infection symptoms occurred in most patients, with some patients rapidly developing acute respiratory distress syndrome and acute respiratory failure [3] . On January 7, 2020, a novel coronavirus was identified from the throat swab sample of a patient. The virus was temporarily termed as 2019-nCoV by the World Health Organization (WHO) which on February 11 formally named the pneumonia caused by 2019-nCoV as COVID-19 [4] . The novel coronavirus rapidly spread across the whole of China mainly through the droplet transmission and contact transmission [5, 6] . By On February 18, 2020, China's NHC published Diagnosis and Treatment of the Novel Coronavirus Pneumonia (Trial Version Six) [6] . It indicated that radiological examinations, including computed tomography (CT) and digital photography (DR), were effective methods for the screening, diagnosis and progress assessment of COVID-19 [6, 7] . However, most radiologists and technologists in radiology departments had little experience of dealing with patients with COVID-19. In one regard, rare differential diagnosis guidelines were present for COVID-19; and in another, nonstandard prevention of COVID-19 when giving radiological examinations had reportedly caused many infections in radiologists and technologists in China. In order to make clear the imaging features of COVID- 19 [6] . At present, patients with COVID-19 are the main source of infection. Respiratory droplets and contact transmission are the main routes of transmission, and people are generally susceptible [6] . Based on current epidemiological data, the incubation period may last for 1-14 days, mostly 3-7 days [6, 8] . The main manifestations are fever, fatigue and a dry cough. A few patients have also had nasal obstruction, a runny nose, diarrhea and other symptoms. More serious cases are often followed by breathing difficulties 7 days later and severe cases will rapidly develop to acute respiratory distress syndrome, septic shock and intractable metabolic acidosis and coagulation dysfunction. The severe cases developed rapidly into acute respiratory distress syndrome, septic shock, metabolic acidosis and coagulation dysfunction. Serious and severe cases may be indicated by low or mild fever, or even no fever at all. Some patients may have no pneumonia, only low fever and slight asthenia. These patients mostly recover after 7 days. From the current cases, deaths are mostly found in the elderly and those with chronic basic diseases. Coronavirus Pneumonia (Trial Version Six) in which cases with a confirmed history of exposure to Wuhan, close contact with people from Wuhan or confirmed patients during the past 14 days were firstly considered [6] . For suspected case, it presents at least two of the following conditions: ① fever and/or respiratory symptoms (eg, cough, myalgia, fatigue); ② imaging features of viral pneumonia; ③ normal or low white blood cell count or reduced lymphocyte in early onset. However, the number of the patients with unknown exposure history is reportedly increasing. If suspected cases have at least one of the following pieces of etiological evidence, they will be confirmed as having COVID-19: ① positive real-time fluorescence polymerase chain reaction of patient's respiratory or blood specimen for COVID-19 nucleic acid; ② viral gene sequences in the respiratory or blood specimen are highly homologous to COVID-19. Doctors or nurses should isolate suspected and confirmed cases as soon as they are identified, and should be reported to the centers for disease control within 2 hours [8] . Suspected case will be excluded if two consecutive respiratory virus nucleic acid tests are negative (sampling interval time≥1d) [6, 8] . Continuous nucleic acid detection is necessary in cases of highly clinical suspicion. China's NHC has indicated that radiological examinations, including CT and DR, are of great important for the screening, diagnosis and progress assessment of COVID-19 [6] . In comparison with laboratory examinations, radiological examinations are fast and highly efficient. However, since DR is not sensitive for the detection of ground-glass opacity (GGO), it was not recommended as the first-line imaging modality for COVID-19, thin-slice CT examination is optimally suggested [9, 10] . For most critical patients, however, DR is a necessary and optimal imaging approach. For chest DR, the scanning settings and parameters for patients with COVID-19 are nearly the same as the patients with other pneumonia. High kV (120 kV) is suggested for adults and low kV (55-65 kV) for children. For severe patients in isolation yard, clinical photography is suggested. Generally, bilateral multifocal consolidation can be seen in severe patients ( Figure 1 ), partially fused into massive consolidation with small pleural effusions and even presenting with "white lung" [11] . The features of COVID-19 are nonspecific and varied. It has been reported that multifocal patchy GGOs with subpleural distribution were found in many patients with mild COVID-19, and diffuse heterogeneous consolidation with GGO was found when being in severe conditions [11, 12] . Our experience classifies four stages as follows. Multiple or pure GGO(s) with inhomogeneous density are often found in the peripheral lung or subpleural area, accompanied by thickening blood vessels and thickening bronchus. During this period, the consolidation lesion is always small and limited, often with irregular or fan-shaped distributions ( Figure 2 ). The lesions enlarge and multiple lesions are merged into one or more large complex lesions in a form of fusion. During this period, the lesions progress and change rapidly, and air bronchogram is always found (Figure 3) . (Table 1) [6, 8] . For each level of protection, hand hygiene is necessary [13, 14] . The radiographers for clinical photography, DR and CT examinations are recommended to be quarantined for a 14-day period in a specific dedicated isolation ward to undergo medical observation after working for days working in the isolation area and before returning to their normal work [16] . 4.4.1 Wipe disinfection: It is appliable to device or floor disinfection, and 75% alcohol or 500-1000 mg/L chlorine-containing disinfectant is suggested [17] . The DR or CT devices should be rigorously disinfected after each examination of patients with COVID-19. 4.4.2 Air disinfection: Ultraviolet irradiation (no less than 70 μW/cm 2 ) lasting for 30-60 minutes is suggested for the examination rooms after each examination. Spraying disinfection is also optional, by using 400-600 mg/L chlorine dioxide, 5000 mg/L peracetic acid or 1000 mg/L chlorine-containing disinfectant [18] . Reusable protective products, such as protective goggles, are suggested to be given a soak disinfection with 500 mg/L chlorine-containing disinfectant or 75% alcohol for at least 30 min. All waste from patients with COVID-19 is considered as infectious medical waste, which shall be managed in strict accordance with the following process: ① the infectious waste must be placed in the medical waste collection bag (double layer, no more than 3/4 full); ② the bag must be sealed with a gooseneck knot and sprayed with 5000mg/L chlorine-containing disinfectant; ③ paste special identifications in the outer layer, and store it in the specialized site for medical waste [19] . In conclusion, radiological examination, especially chest CT, plays an irreplaceable role in the diagnosis of patients with COVID-19. Radiologists, technologists and nurses understand correctly individual protection and disinfection requirements when working in radiological departments. 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