The key role of CT chest imaging in detection, follow-up, and management of patients with COVID-19
Imaging played a key role in the fight against COVID-19 epidemic from an early stage, especially CT imaging, which has become the go-to imaging test when COVID-19 is suspected.
Imaging is not intended to replace PCR tests for mass detection of infected people. The chest CT scan is rather a second-line option in patients who have been diagnosed or are suspected, with initial or secondary signs of clinical severity and in the context of hospital management and in accordance with recommendations of the SFR (Société Française de Radiologie).
The relevance of the chest scan
The chest scanner demonstrates its relevance in COVID-19 positive patients who present with worsening. In this context, the examination must seek and assess the extent of lesions such as areas of ground glass or alveolar consolidations.
For many years, Intrasense has been developing tools for chest CT and lung analysis. This is particularly the case with its clinical application Myrian XP-Lung, which allows segmentation and quantification of different lung volumes, as well as the airways. It is based on this clinical application that Intrasense development teams have worked to develop, as a world premiere, a new CT imaging protocol entirely dedicated to COVID-19. The main goal of this clinical application is to provide an objective measurement of lung damage and available lung reserve in patients in an automatic and intuitive way. This new protocol makes it possible to measure the overall lung volume, healthy lung areas, pathological areas, whether they are frosted glass, "crazy paving" (superposition of frosted glass and intra-lobular reticulations) or in consolidations, which makes it possible to obtain a healthy lung volume ratio / overall lung volume and to obtain the pulmonary reserve as well as a histogram of densities on the complete lung volume. There are many clinical interests, particularly in the context of screening, analysis of the pathological stage, clinical development or even in monitoring the therapeutic response.
An effective diagnostic tool
The COVID-19 epidemic has slowed in Europe where there is a slight trend of resumption in some limited geographic areas. Overall the trend is for an acceleration of the circulation of the virus with a significant increase in the number of daily cases. In this context, it is essential for radiologists and clinicians to have the right diagnostic tools to cope with large crowds and a strong need for the assessment of pathological stage. It is therefore essential to be quickly able, to determine an assessment of pathological stage and thus to decide on the patient's care, the prediction of his clinical evolution and his orientation towards the right hospital service (intensive care unit, continuing care department, etc…).
The goal in performing CT scans in patients with COVID-19 is to determine the extent of the lesions throughout the lungs. To do this, it is essential to determine with the greatest precision the overall volume of the lungs. Myrian, with COVID-19 clinical application performs this operation automatically by operating a lungs segmentation (right and left lobes).
The radiologist can then objectively determine the extent of the lesions, which will allow him to grade the pathology stage of the patient by viewing a histogram showing the density values (abscissa) and their quantity (ordinate). It is quite possible to determine the overall lung volume, the lesion volume, as well as to determine the patient's pulmonary reserve volume, or the healthy lung volume. Note that the COVID-19 protocol also allows to calculate vascular volume to improve accuracy.
This dedicated protocol is a class 2a medical device intended for diagnosis.