HRCT chest in COVID-19 patients: An initial experience from a private imaging center in western India

Abstract

The COVID-19 pandemic began in late December in 2019 and has now reached to 216 countries with 1,08,42,028 confirmed cases and 5,21,277 deaths according to the WHO reports and 6,49,666 confirmed cases in india alone with 18,679 deaths (as on 04^th july 2020). RT-PCR has been considered the standard test for diagnosis of COVID 19. However, there has been reported a high false negative rate. This high false negative rate increases the risk of further transmission as well as delays the timely management of suspected cases. We have conducted HRCT chest of various (200 patient case study) proven and suspected cases of COVID-19 infection in the months of April, May and June 2020. Out of 200 scanned patients with clinical complains and suspicion, positive HRCT chest findings were seen in 196 patients, showing clinical-radiological correlation and an accuracy of 98%. The sensitivity of chest CT in suggesting COVID-19 was 98.6% (146/148patients) based on positive RT-PCR results. In patients with negative RT-PCR results and high clinical suspicion, 90% (18/20) had positive chest CT findings. HRCT chest is very sensitive and accurate in picking up lung parenchymal abnormalities in laboratory negative RT-PCR cases with high clinical suspicion of COVID-19 infection and also in all symptomatic patients where RT-PCR was not done. HRCT can also be very sensitive, cost effective and time effective in screening patients with high clinical suspicion. HRCT scores over RT-PCR in giving immediate results, assessing severity of disease and prediction of prognosis. We suggest HRCT chest for detection of early parenchymal abnormalities, assessing severity of disease in all patients with clinical symptoms and suspicion of COVID infection irrespective of laboratory RT-PCR status.

Keywords: CT scan COVID-19; Diagnosis COVID-19; HRCT chest in COVID-19; Imaging in COVID-19; Radiology in COVID-19.

Chart 1

Results of HRCT findings and laboratory RT-PCR findings of 200 patients

Figure 1 (A and B)

(A) Mildly symptomatic patient with low-grade fever and throat pain showing classic peripheral GGOs consistent with viral pneumonitis. This patient tested RT-PCR positive done after imaging. (B) Mildly symptomatic patient with low-grade fever and throat pain showing classic peripheral GGOs consistent with viral pneumonitis. This patient tested RT-PCR positive done after imaging

Figure 2

Mildly symptomatic patient with fever and mild chest pain showing classical sign of bilateral GGO. RT-PCR was not done on this patient and the patient was asked to remain in isolation and receive treatment at home. The patient's condition has improved since

Figure 3

An elderly patient with multiple comorbidities and severe breathlessness and fever showing bilateral GGOs, underlying interstitial fibrosis and traction bronchiectasis. Patient had tested positive with RT-PCR after the scan and unfortunately, this patient died due to respiratory complications after 4 days of scans. ARDS type of imaging findings is not typical and frequent finding in COVID-19 infection

Figure 4 (A and B)

(A) GGO, interstitial thickening, crazy paving and traction bronchiectasis in markedly symptomatic patient having high-grade fever and breathlessness. RT-PCR proven case of COVID infection. (B) GGO, interstitial thickening, crazy paving and traction bronchiectasis in markedly symptomatic patient having high-grade fever and breathlessness. RT-PCR proven case of COVID infection

Figure 5 (A and B)

(A) This patient had severe breathlessness with fever and increased D-dimer. Imaging findings showed peripheral GGOs and consolidations on lung window. In this patient, initial RT-PCR was negative; however, after high clinical suspicion and positive imaging findings, repeat RT-PCR was done which turned out to be positive. (B) This patient had severe breathlessness with fever and increased D-dimer. Contrast images in soft tissue window showed partial pulmonary thromboembolism (arrow marks). In this patient, initial RT-PCR was negative; however, after high clinical suspicion and positive imaging findings, repeat RT-PCR was done which turned out to be positive

Figure 6 (A and B)

(A) Initial HRCT chest of a symptomatic RT-PCR proven COVID patient showing GGOs, focal consolidation, and mild fibrosis in bilateral lungs. (B) HRCT chest of the same patient done 10 days later shows marked resolution of GGO and fibrosis. Patient had improved clinically