This retrospective analysis was approved by institutional review board. The requirement to obtain patient consent was waived. Patients at Taizhou Enze Medical Center (Group) Enze Hospital were evaluated from January 19, 2020, to February 4, 2020. During this period, chest CT and RT-PCR (Shanghai ZJ Bio-Tech, Shanghai, China) were performed for consecutive patients who presented with (a) a travel history to or residential history in Wuhan or local endemic areas or contact with individuals from these areas with fever or respiratory symptoms within 14 days and (b) fever or acute respiratory symptoms of unknown cause. In the case of an initial negative RT-PCR test, repeat testing was performed at intervals of 1 day or more. We included all patients who underwent both unenhanced chest CT (slice thickness, 5 mm) and RT-PCR testing within an interval of 3 days or less and in whom COVID-19 infection was eventually diagnosed by means of RT-PCR testing (Fig 1). Typical and atypical chest CT findings were recorded according to CT features previously described for COVID-19 (4,5). The detection rate of COVID-19 infection based on the initial chest CT and RT-PCR findings was compared. Statistical analysis was performed by using the McNemar χ2 test, with P < .05 indicative of a statistically significant difference.
In our series, the sensitivity of chest CT was greater than that of RT-PCR (98% vs 71%, respectively; P < .001). The reasons for the low efficiency of viral nucleic acid detection may include (a) immature development of nucleic acid detection technology, (b) variation in detection rate from different manufacturers, (c) low patient viral load, or (d) improper clinical sampling. The reasons for the relatively lower detection rate with RT-PCR in our sample compared with a prior report are unknown (3). Our results support the use of chest CT to screen for COVID-19 in patients with clinical and epidemiologic features compatible with COVID-19 infection, particularly when results of RT-PCR tests are negative.
Reference & Source information: https://pubs.rsna.org/
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