Indian Journal of Nuclear Medicine

LETTER TO THE EDITOR
Year
: 2020  |  Volume : 35  |  Issue : 3  |  Page : 276--277

Incidental COVID-19 pneumonia on fluorodeoxyglucose positron emission tomography-computed tomography: The “new-normal”


Punit Sharma 
 Department of Nuclear Medicine and PET-CT, Apollo Gleneagles Hospitals, Kolkata, West Bengal, India

Correspondence Address:
Dr. Punit Sharma
Department of Nuclear Medicine and PET-CT, Apollo Gleneagles Hospitals, 58, Canal Circular Road, Kolkata - 700 054, West Bengal
India




How to cite this article:
Sharma P. Incidental COVID-19 pneumonia on fluorodeoxyglucose positron emission tomography-computed tomography: The “new-normal”.Indian J Nucl Med 2020;35:276-277


How to cite this URL:
Sharma P. Incidental COVID-19 pneumonia on fluorodeoxyglucose positron emission tomography-computed tomography: The “new-normal”. Indian J Nucl Med [serial online] 2020 [cited 2020 Sep 24 ];35:276-277
Available from: http://www.ijnm.in/text.asp?2020/35/3/276/288474


Full Text



Sir,

The coronavirus disease 2019 (COVID-19) pandemic is sweeping through the globe with >3.5 million cases and 0.25 million deaths at the time of writing this article.[1] While India has been able to stall rapid progression of cases till now, it is likely that the infection will creep through the population over time until a vaccine is available. It has been reported that >80% of those infected have no or minimal symptoms and hence may remain undetected and untested. Also, while the specificity of the currently available reverse transcription-polymerase chain reaction (RT-PCR) test being used to confirm the infection is very high, the sensitivity is modest at ~70%.[2] Hence, it is quite likely that we will incidentally keep seeing such undetected/asymptomatic cases during routine clinical positron emission tomography-computed tomography (PET-CT) scanning. In many instances, such as patients with underlying advanced cancers, the symptoms may be masked or not looked for. Therefore, it is vital that we maintain a high index of suspicion when evaluating clinical PET-CT images to not miss COVID-19 findings.

COVID-19 being a pulmonotropic virus, the findings are usually limited to lungs with possible secondary changes in draining nodes. The classical findings are peripheral ground-glass opacities (GOO's) and peripheral consolidations, predominantly involving the lower lobes, with the absence of pleural effusion.[3] Increased fluorodeoxyglucose (FDG) uptake can be seen in the above lesions with uptake varying from mild to high. Significant lymph node enlargement is usually not seen, but increased FDG uptake in draining nodes might be seen. However, we must remember that manifestations of underlying diseases such as cancer or renal failure might complicate the imaging findings. Pleural effusion or pulmonary edema or aspiration pneumonia can impair our imaging judgment. I would present two such cases of incidental COVID-19 pneumonia detected on FDG PET-CT, which we encountered in our clinical practice.

The first patient, a 44-year-old male, had a history of fever for 2 weeks. He was a known case of end-stage chronic kidney disease V and waiting for transplantation. He had a history of recurrent bilateral pleural effusion, more marked on the left side, which was drained twice and was negative for infection. A HRCT chest done 5 days back showed only effusion. FDG PET-CT was done for fever workup [Figure 1], which showed bilateral pleural effusion (b and c, *) and liver lesion suspicious for an abscess (d and e, bold arrow). Also seen was bilateral lung minimally FDG-avid ground-glass opacities with few focal subpleural consolidations (b and c, arrows), raising suspicion of COVID-19 pneumonia. A RT-PCR test from nasal swab was positive for COVID-19. The lives lesion showed pyogenic abscess with the growth of Gram-negative bacteria. The second patient, a 58-year-old female, known case of gastric adenocarcinoma with bone metastases, underwent FDG PET-CT [Figure 2] for assessing chemotherapy response. Bilateral lung mildly FDG avid ground-glass opacities with few focal subpleural consolidations (b and c, arrows) were seen, raising suspicion of COVID-19 pneumonia. Non FDG-avid calcified mediastinal and hilar nodes were seen (d, bold arrows), sequel of prior granulomatous infection. Bilateral mild pleural effusion was also seen (b and c, *). Also seen were residual mildly FDG avid sclerotic bone metastases (e). RT-PCR test from nasal swab was positive for COVID-19. She passed away 5 days later due to complications of COVID-19 pneumonia. These cases highlight that incidental detection of COVID-19 pneumonia in routine PET-CT practice will become the new normal in the foreseeable future, and we need to be vigilant so as to not miss these findings. Also, the findings will always not be textbook perfect and may be overlapped by the sequel of underlying non-COVID-19 pathology.{Figure 1}{Figure 2}

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1Available from: https://www.worldometers.info/coronavirus/. [Last accessed on 2020 May 03].
2Ai T, Yang Z, Hou H, Zhan C, Chen C, Lv W, et al. Correlation of chest CT and RT-PCR testing in coronavirus disease 2019 (COVID-19) in China: A report of 1014 cases. Radiology. 2020 Feb 26;200642. doi: 10.1148/radiol.2020200642.
3Qin C, Liu F, Yen TC, Lan X. 18F-FDG PET/CT findings of COVID-19: A series of four highly suspected cases. Eur J Nucl Med Mol Imaging 2020;47:1281-6.