Diagnostic accuracy of chest computed tomography for detecting COVID-19 pneumonia in low disease prevalence area: A local experience

Mounir Benmessaoud, Ahmed Dadouch, Maghnouj Abdelmajid, Anass Abir, Youssef el-Ouardi, Assiya Lemmassi, Khalid Nouader, Inssaf Chibani

Abstract


Background: The role of computed tomography (CT) was crucial in detecting coronavirus disease 2019, their diagnostic performances were evaluated frequently in the high disease prevalence regions. In contrast, limited studies assessed the accuracy of chest CT in low disease prevalence areas.

Methods: A retrospective study was conducted at a single center from April 3 to October 16, 2020. The data were collected manually involving age, gender, symptoms, chest CT and RT-PCR results. Patients included were all suspected cases diagnosed by both chest CT and RT-PCR. The confidence intervals (95%) were estimated using the Wilson method.

Results: A total of 104 patients (mean age 59±15 years, 61 males) were included. 6/104(15%) were presented with fever, 22/104(21%) with cough, 19/104(18%) with dyspnea, 4/104(4%) with diarrhea, and 7/104(6%) with headache. Regarding reverse transcription-polymerase chain reaction (RT-PCR) tests, 34 cases were positive and 70 were negatives. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of chest CT using RT-PCR as a reference were 97% (33/34,95%CI; [85-99%]), 50% (35/70,95%CI; [38-61%]), 48% (33/68,95%CI; [37-60%]), 97% (35/36,95%CI; [85-99%]) and 65% (68/104,95%CI; [56-74%]), respectively.

Conclusion: Chest CT is an important tool that contributed to the treatment decision of the high-suspected cases, as an early intervention before the confirmation with RT-PCR.

Keywords: COVID-19; Chest Computed Tomography; Diagnostic Accuracy 


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