key: cord-1000110-dhwttplp
authors: Wu, Jing; Tang, Jie; Zhang, Tao; Chen, Yu‐Chen; Du, Chao
title: SARS‐CoV‐2 Delta VOC pneumonia with CT follow‐ups: A case report
date: 2021-10-06
journal: J Med Virol
DOI: 10.1002/jmv.27361
sha: 1ea3a2ec792a2da0cc227b3d745016786b118804
doc_id: 1000110
cord_uid: dhwttplp

The outbreak of the Coronavirus Disease 2019 (COVID-19) has quickly happened worldwide, and mutated. The most typical imaging manifestations of unmutated COVID-19 had been reported by many literatures. However, the imaging manifestations of pneumonia caused by the mutant strain delta are still unfamiliar to us. This article will introduce a typical case of pneumonia caused by Delta Variant of Concern (VOC)through computed tomography (CT) follow-ups in order to improve readers' understanding of its imaging manifestations and changes. This article is protected by copyright. All rights reserved.

A 54-year-old male patient took a flight from Moscow to Nanjing at Nanjing Lukou Airport on July 10, 2021. Nasopharyngeal nucleic acid test results at the airport were negative. On July 14, the patient was admitted to our hospital due to a fever (38°C), accompanied by headache, fatigue, and muscle aches. The nucleic acid test was positive after admission. The white blood cells were normal, the percentage of neutrophils was 75.9%, the percentage of lymphocytes was 10.4%, the absolute value of lymphocytes: 0.72 × 10 9 /L, C-reactive protein 3.02 mg/L. A total of four computed tomography (CT) examinations were performed in our hospital, as shown in Figure 1 . All CT examinations were performed with a 16-section scanner (Toshiba) without injecting contrast media. The radiation dose for CT scan was 120 kV/129 mAs/278.59 mGy·cm. The patient's symptoms and laboratory tests are shown in Tables S1 and S2.

The current study was approved by the Research Ethics Committee of the Second Hospital of Nanjing.

The first vertical images are the initial CT (2021-7-19, Figure 1A Compared with previous CT, the density and size of nodules increase (B5), and some of the nodules appear to fuse into patches, as shown in Figure 1 (B1-B4) . The distribution is mainly in the secondary lung lobules and peripheral lung zone. The third vertical images are the follow-up CT (2021-7-26, Figure 1C ). C1-C5 correspond to the same level as the previous CT. Through the local enlargement, the lesion becomes smaller, indicating that the lesion has improved. The fourth vertical images are follow-up CT (2021-7-31, Figure 1D ). Lesions were further reduced by contrasting the same level with the previous images (D1-D5), and the edge was straight, like D4, indicating that the lesion has entered the repair period.

The early manifestation is ground-glass opacity (GGO), with the distribution of secondary lung lobules mainly as per Figure 2A .

With the aggravation, the size and density of the lesion increase may form nodules with halo signs as in Figure 2B . Then the nodules merge into patches as Figure 2C . If the disease further aggravates, diffuse high-density shadows could be found, which mostly happened in severe patients. 7 As the disease improves, the patchy high-density shadow gradually shrinks, and the edges may appear straight, as in Figures 2D,E, or there may be a fine grid sign inside, or a striped shadow around it, which indicates that the disease has entered the repair period and is gradually absorbed as in Figure 2F .

In this case, the boundary of GGO is blurred. 8 Other viruses, such as influenza viruses, are more manifested as GGO distributed under the pleura of bilateral lungs, rather than secondary lung lobules, and fewer nodules can be found. 9, 10 As for the CT difference between unmutated COVID-19 and delta variant pneumonia, there is no literature report, and further research is needed.

This report introduces a typical case of SARS-CoV-2 Delta VOC pneumonia through multiple follow-up CT. The early manifestations were GGN or nodules with halo signs with the distribution of secondary lung lobules and then fused into patches. CT examination can be used as a supplementary method for the diagnosis, and to judge and evaluate the development of the disease.

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