The Sensitivity of Chest CT for the Diagnosis of Covid-19 Pneumonia and Imaging Patterns as Seen on Chest CT :A Crossectional Prospective Study Done in Addis Ababa
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Date
2021
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Addis Abeba University
Abstract
Background:
Coronavirus disease 2019 (COVID-19) is a respiratory illness caused by a novel coronavirus
designated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).
The infection
widely and rapidly spread all over the world with significant impacts upon the sociopolitical milieu
and healthcare delivery systems. On 11 March 2020 COVID-19 was declared a pandemic by WHO
(2)
and on March 13, 2020, the first confirmed COVID-19 case was reported in Ethiopia. The
clinical presentation spectrum varies and includes mild to moderate symptoms, severe symptoms,
and critical illness.
(2)
Although RT PCR test has been considered to be the gold standard, chest
imaging especially has an adjunct role not only in the diagnosis but in the assessment of the
severity of the disease and identification of complications.
(3)
Identification of the typical imaging
pattern and degree of involvement is important to guide and plan treatment.
Objective: The study was conducted to assess the sensitivity of chest CT scan as compared to the
standard RT PCR for the diagnosis of COVID-19 and also to determine the different chest CT
imaging patterns and severity of COVID-19 pneumonia.
Method: A crossectional study was conducted based on data collected from different diagnostic
centers and treatment centers from July 1, 2021, to October 1, 2021. The chest CT of the patients
was reviewed and a structured questionnaire was filled on a Google form sheet. The data were
exported and analyzed on SPSS version 26.
Result: Among a total of 193 patients included in this study, 116 (60.1%) were males and 77
(39.9%) were females with a mean (SD) age of 50±14.2 years. Among patients for whom data
regarding previously known comorbidities was available hypertension and diabetes mellitus
accounted for 26 (61.9%), and 25 (59.5%) respectively. Of 107 patients whose presenting
complaints were available, cough was the most common complaint seen in 82 (76%) of the
patients, followed by shortness of breath in 65 (60.7%), chest pain in 36 (33.6%), and fatigue in
26 (24.3%). Using the RT PCR result as a gold standard the sensitivity, and specificity of chest
CT were found to be 82.9 % and 16.7% respectively. The chest CT distribution showed that 95.9%
of the cases were bilateral and 51.3 % had a peripheral distribution. Among the typical chest CT
patterns, 157(83%) of the CT images showed GGO, 152(80.4%) consolidation, and 68(35.4%)
showed broncho-vascular thickening.
The mean chest CT severity score was 13.6±6.2 and 95 (49.2%) patients had a score of >18
(severe). A positive correlation was identified between CT severity score with age and diabetes
with a P-value < 0.01.
Conclusion: This study demonstrated that chest CT has a high sensitivity (82.9%) in the
diagnosis of COVID-19 pneumonia. Ground glass opacity, consolidation, and bronchovascular
thickening were the predominant features seen with a predominant bilateral, basal, and peripheral
distribution. The study also revealed chest CT severity score is positively correlated with age and
comorbidity of DM.
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Keywords
COVID-19, chest CT, RT-PCR, Cross-sectional study