“Pulmonary target sign” as a diagnostic feature in chest computed tomography of COVID-19

BACKGROUND In chest computed tomography(CT)scan,bilateral peripheral multifocal groundglass opacities,linear opacities,reversed halo sign,and crazy-paving pattern are suggestive for coronavirus disease 2019(COVID-19)in clinically suspicious cases,but they are not specific for the diagnosis,as other viral pneumonias,like influenza and some viral pneumonia may show similar imaging findings.AIM To find a specific imaging feature of the disease would be a welcome guide in diagnosis and management of challenging cases.METHODS Chest CT imaging findings of 650 patients admitted to a university Hospital in Tehran,Iran between January 2020 and July 2020 with confirmed COVID-19 infection by RT-PCR were reviewed by two expert radiologists.In addition to common non-specific imaging findings of COVID-19 pneumonia,radiologic characteristics of“pulmonary target sign”(PTS)were assessed.PTS is defined as a circular appearance of non-involved pulmonary parenchyma,which encompass a central hyperdense dot surrounded by ground-glass or alveolar opacities.RESULTS PTS were presented in 32 cases(frequency 4.9%).The location of the lesions in 31 of the 32 cases(96.8%)was peripheral,while 4 of the 31 cases had lesions both peripherally and centrally.In 25 cases,the lesions were located near the pleural surface and considered pleural based and half of the lesions(at least one lesion)were in the lower segments and lobes of the lungs.22 cases had multiple lesions with a>68%frequency.More than 87%of cases had an adjacent bronchovascular bundle.Ground-glass opacities were detectable adjacent or close to the lesions in 30 cases(93%)and only in 7 cases(21%)was consolidation adjacent to the lesions.CONCLUSION Although it is not frequent in COVID-19,familiarity with this feature may help radiologists and physicians distinguish the disease from other viral and noninfectious pneumonias in challenging cases.

Diagnostic Value of Spiral CT Chest Enhanced Scan in Adult with Active Pulmonary Tuberculosis

Aim:To explore the diagnostic value of spiral CT chest enhanced scan for adults with active pulmonary tuberculosis.Methods:The clinical data of 60 adult patients with active pulmonary tuberculosis who were treated in our hospital from January 2018 to November 2019 were retrospectively analyzed.All patients underwent conventional chest radiography and spiral CT chest enhanced scan.The number of tuberculosis diagnosis,the detection rate of special site lesions,and the detection rate of active pulmonary tuberculosis signs by the two methods were compared.Results:In 60 patients,the pathological results confirmed the existence of 75 tuberculosis lesions.The detection rate of spiral CT was 98.67%,which was not statistically significant compared with the detection rate of 92.00%(P>0.05)in the conventional chest X-ray.The detection rate of spiral CT enhanced scans for tuberculosis lesions in special sites was 100.00%,which was significantly higher than that of conventional chest X-ray of 7.69%,and the accuracy rate of active pulmonary tuberculosis signs was 98.85%higher than that of conventional chest X-ray of 79.31%.P<0.05).The difference was statistically significant(P<0.05).Conclusion:Spiral CT chest enhanced scan can not only find special tuberculosis lesions that cannot be detected by conventional chest radiography,but also accurately determine active pulmonary tuberculosis in adults,which is of high diagnostic value.