Primary and prospective imaging of the chest using magnetic resonance imaging in patients with viral lung damage in COVID-19
Authors: Ussov W. Yu. , Nudnov N. V. , Ignatenko G. A. , Gulyaev V. M. , Pervak M. B. , Shelkovnikova T. A. , Dubovaya A. V. , Bergen T. A. 
Published: December 2020

Puropose of the study. Basing on the previously obtained results on the proven high efficiency of magnetic resonance imaging (MRI) of the chest organs in the visualization of major lung diseases, in the current period of mass incidence of viral pneumonia (VP) caused by COVID-19, we tried to study the possibility of using MRI OGK to image lung damage in this pathology both in primary detection and for follow-up reconvalescence control.

Material and methods. MRI of the chest in T1 -, T2-weighted modes (T1-w, T2-w), also with fat suppression, diffusion-weighted, STIR-modes, in the axial and frontal planes, with breath holding, or with automatic synchronization of acquisition with breathing was carried-out in 47 patients with VP of various severity, 32 of them were confirmed by PCR as COVID-19, all did have a clinic of pneumonia. The control group comprised 15 volunteers, of them 8 non-smokers, and 7 smokers. In 18 patients, an CT study of the chest was also performed, with a step of 0.5–1.25 mm, with full coverage of the chest and reconstruction of axial and frontal slices, with a comparison of MRI and CT of the chest. In 8 patients, MRI of the chest was then performed again, for follow-up control of clinical recovery. There were no deaths among our patients

Results. The duration of a complete MRI examination of the chest was less than 25 minutes in all cases (21 ± 4 minutes on average), and less than 10 minutes in the chest CT. In all cases, MRI imaging of the affected area was achieved using a group of MRI protocols, which included axial T1-w and axial and frontal T2-w, and lasted < 12 minutes, counting the time for laying the patient.

In normal patients without pathology of the lungs, not smoking, the lung was visualized as a diffuse homogeneous air region with a minimum share interstitial and vascular space. In patients - smokers, lung MRI was slightly enhanced in the dorsal parts of both lungs, disorders of airiness and interstitial exudative changes weren't present. In the acute phase of the disease, pulmonary ventilation disorders and interstitial exudative changes that form the morphological basis of lung damage in COVID-19 were visualized as local, corresponding to the location and nature (sub-segmental, segmental, polysegmental) of the pathological focus, both T1-w and T2-w modes. MRI of the chest provided diagnosis of lung pathology in all cases, while the extent of the pathological focus on the MRI image in T2-w was 14–19% greater than on the CT. The correlation of the calculated volume of affected lung tissue between CT and MRI of the chest wasas high as r = 0.95 (p < 0.001). The values of the volume of the affected tissue in T1-w and T2-w did not differ from each other in the intergroup comparison and correlated strongly and reliably, r = 0.985 (p < 0.001). MRI in DWI mode showed a sensitivity of 81% (38/47) in detecting COVID-lung lesions. The duration of DWI in all cases was more than 6 minutes, more than twice as long as all other MRI protocols together. The volume of pleural effusion, clearly visible with T2-VI, in all our cases did not exceed 100 ml. In a prospective follow-up of 8 patients with COVID-19, chest MRI ptovided evidence-based visualization of the recovery process in all cases, with a decrease or complete regression of the exudation component.

Conclusion. MRI of the chest with respiratory synchronization or with breath-holding can be used for early diagnosis of inflammatory lung lesions in COVID-viral pneumonia and for subsequent follow-up control, is not accompanied by radiation exposure and closely correlates with the results of chest CT recruited as a modern standard for the diagnosis of pneumonia.