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The COVID-19 pandemic has proved difficult to control in part due to inadequate detection.1 Presentations vary greatly with some persons experiencing almost no symptoms.2 To date, there are few descriptions of the infection on MRI and this gap in knowledge may contribute to missed opportunities to diagnose the disease. Here we describe the diagnostic challenges emerging from the detection of incidental lesions in the lung bases on liver MRI in a 49-year-old woman.
The patient presented to the emergency department with tachycardia, vertigo, fever and a non-productive cough. Blood tests revealed serum alanine transaminase of 69 IU/L and alkaline phosphatase of 323 IU/L. Reverse transcriptase PCR (RT-PCR) respiratory swab for 2019 novel coronavirus (2019-nCoV) RNA at the time of arrival was negative. Ultrasound of the liver showed hepatic steatosis and a hypoechocic lesion. A standard protocol liver MRI performed to further characterise the hepatic lesion diagnosed two liver haemangiomata and confirmed steatosis. The liver MRI also obtained limited slices of the lung bases which demonstrated non-specific areas of peripheral high signal on the T2-weighted imaging with focal areas of restricted diffusion on diffusion-weighted imaging (DWI) in the left lower lobe (figure 1).
The day after her MRI the patient underwent a CT of the thorax, abdomen and pelvis for weight loss. The CT uncovered multiple ground glass opacities in a bilateral, multilobar and peripheral distribution, corresponding to the British Society of Thoracic Imaging classification of, classic/probable COVID-19 infection.3 Figure 2 shows the CT. Appropriate precautions were taken to avoid transmission and the patient had a repeat 2019-nCoV RNA respiratory swab which again produced a negative result.
This case provides early insight into a clinical dilemma that may arise more frequently in the later parts of the COVID-19 pandemic as the frequency of routine MRI and MRI for non-respiratory conditions increases. The lack of sensitivity of RT-PCR and the poor specificity of thoracic CT, which are currently the two most commonly used diagnostic tests for COVID-19 infection, make it difficult to draw definite conclusions about suspicious lesions on MRI.4 5
At the time of writing this report, all published examples of pulmonary COVID-19 on MRI are descriptive.6–8 The limited available data primarily from thoracic MRI, however, suggest that on liver and abdominal imaging protocols, COVID-19 presents as lung lesions with: high T1 signal due to partial alveolar collapse and higher tissue density, high T2 signal caused by oedema or consolidation, high DWI signal because of increased cell density from the inflammatory reaction and partial collapse, and with a heterogeneous enhancement pattern after contrast administration. There remains a need to validate these descriptions with a large sample size and with comparison to a standard which at the present time could be RT-PCR or an ELISA quantitative serology test. In this way, the diagnostic value of MRI can be better assessed which could ultimately lead to more appropriate management decisions in future cases that present similarly to the patient described here.
During the COVID-19 pandemic, consideration should be given that incidental lung lesions on MRI could represent COVID-19 infection, particularly in abdominal MRI where the lung bases can often be overlooked.
As the frequency of routine MRI increases in the latter parts of the COVID-19 pandemic, it is likely that the finding of incidental lung lesions on MRI will rise.
There is a need for more reliable diagnostic tests and better descriptors of COVID-19 infection on common abdominal MRI sequences so that the correct management decisions can be made when incidental lesions are detected such as in the case of the patient described here.
The authors thank the Department of Radiology at Addenbrooke’s Hospital, Cambridge University Hospitals NHS Foundation Trust and all the medical staff responsible for the care of the patient discussed here.
Contributors SSD obtained consent from the patient and contributed to writing the manuscript and producing the figures. MW contributed to the interpretation of the CT and MRI findings in the lungs and to the writing of the manuscript. SK contributed to the interpretation of the CT and MRI findings in the lungs and to the writing of the manuscript. EMG first identified the case, contributed to the interpretation of the abdominal and thoracic CT and MRI findings, assisted in writing the manuscript and in producing the figures.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent for publication Obtained.
Provenance and peer review Not commissioned; externally peer reviewed.
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