Diagnostic value of HRCT-Thorax for pandemic COVID-19 pneumonia in Pakistan

Abstract

Background: In the scenario of, inadequate testing, the low sensitivity of the COVID-19-PCR test, limited availability of testing kits, and low detection rate, we aimed to investigate the usefulness of high-resolution computed tomography of chest (HRCT) for diagnosing pandemic coronavirus (COVID-19) pneumonia.
 Objective: To determine the diagnostic efficacy of HRCT thorax in Covid-19 pandemic pneumonia.
 Materials and Methods: This prospective, cross-sectional study was conducted in the Pulmonology–OPD of Gulab Devi Teaching Hospital, Lahore-Pakistan from 01-04-2020 to 15-07-2020. 121 patients with dry cough, fever, and dyspnea of sudden onset were included while patients with Bronchial Asthma, ILD, Tuberculosis, Bronchiectasis, COPD, and overt heart failure were excluded. Patients were investigated with chest x-ray, HRCT, COVID-PCR, and hematological tests. HRCT films were evaluated by a qualified and experienced radiologist. Findings were summarized, organized and statistical analysis was done by using SPSS-26 software to make an inference.
 Results: Five patients were diagnosed as non-covid. Out of 116-diagnosed covid-19 patients, 38(32.75%) showed sub-pleural consolidation, 19(16.37%) consolidation with air-bronchogram, 29(25.0%) crazy paving sign, one pleural effusion (0.86%) and 18 cases (15.51%) displayed reticulations. 11cases(9.48%) had isolated ground glass appearances, while all categories showed it to variable extent. 65 patients (56.03%) were PCR-positive while 51(43.96) patients with positive-HRCT findings for COVID-19 pneumonia had negative nasopharyngeal-PCR. HRCT-Thorax revealed sensitivity: 97.41 %, specificity: 80%, PPV: 99.12%, NPV: 57.14%, and diagnostic accuracy of 96.69% for COVID-19 pneumonia.
 Conclusion: HRCT-Thorax, having high sensitivity and adequate specificity, can provide foundations for evidence-based early diagnosis and quantification of coronavirus pneumonia. It can be tremendously useful for decision making in PCR-negative patients and anticipating respiratory improvement or decline by serial scans.

Comparison of High-Resolution Computed Tomography and Real-Time Reverse Transcriptase Polymerase Chain Reaction in Diagnosis of COVID-19 Pneumonia in Intensive Care Unit Population

“…In a local study by Qureshi et al, HRCT reported sensitivity and specificity of 97.41% and 80%, respectively, with a positive predictive value of 99.12% and a negative predictive value of 57.14%. Furthermore, they reported the diagnostic accuracy of HRCT for COVID-19 to be 96.69% [ 8 ].…”

“…Due to the reduced sensitivity of RT PCR, many patients remain unidentified. This delays treatment and also contributes to the transmission of COVID-19 infection [8][9][10]. Computed tomography is technically not as demanding as RRT-PCR.…”

“…All HRCT chests were performed in the radiology department by an experienced radiologist. Patients were asked to lay in the supine position with a tube voltage of 120 kV and slice thickness of 1 cm [ 8 ].…”

“…HRCT chest was taken as an index test because, in comparison to RRT-PCR and immunological testing, it is non-invasive, readily available, easy to perform, replicable, and does not depend on the duration of illness. Its reported sensitivity and specificity are 91.9% and 25.1%, respectively [ 8 ].…”

“…On the other hand, a recent study by Qureshi et al reported that high-resolution computed tomography (HRCT) thorax is a substantially useful modality in establishing the diagnosis of COVID-19 pneumonia [ 8 ]. Furthermore, HRCT is less time-consuming and may reveal abnormalities in the lung parenchyma consistent with features of COVID-19 pneumonia in individuals with negative PCR of nasal or throat swab culture results [ 7 ].…”