Evaluation of pulmonary nodules on CT using the Lung-RADS system. Clinical value

ABSTRACT

Abstract Introduction: Inspired by the BI-RADS system (Breast Imaging Reporting and Data System), the American College of Radiology (ACR) developed the Lung-RADS system, for the purpose of making standardized reports on lung nodules detected in lung cancer screening (LCS). In Argentina and in many other parts of the world the LCS is not performed due to high costs; however, in chest CT scans pulmonary nodules frequently appear as incidental findings. There are multiple systems to evaluate them based on a series of features that allow subsequent follow-up. Some of them are the Fleischner Guidelines, the British Thoracic Society Guidelines and the Lung-RADS system, the latter being the only one with numerical categorization. In this article we study the usefulness of the Lung- RADS, as a diagnostic, follow-up method for the classification of pulmonary nodules. Objective: Evaluation of the pulmonary nodule diagnosed on chest CT scan, using the Lung-RADS system to determine its clinical importance, comparing the correlation between this classification and the malignancy or benignancy in the histopathological examination. Material and Method: Descriptive, statistical, observational, retrospective and prospective study. A total of 100 adult patients, both men and women, with a diagnosis of pulmonary nodule were studied between January 2017 and December 2019. Patients without follow-up were excluded. Studies were performed with a 128-slice scanner. The variables under evaluation were patients' sex and age, size and density of the nodule, malignancy of the lesion found in the anatomopathological study, Lung-RADS category and treatment performed and suggested. For the descriptive analysis we used relative frequencies (percentages) and absolute frequencies (number of cases) for qualitative variables; and mean and standard deviation as well as range of minimum-maximum values for the quantitative variables. For hypothesis tests, Chi-Square tests were performed for qualitative variables. For quantitative variables, Shapiro Wilks and Kolmogorov tests were performed. Results: In 100 patients in whom Lung-RADS was applied to determine follow-up and treatment, different types of scenarios could be identified regarding the approach and follow-up some needed recategorization and changes in the diagnostic approach and treatment. As for the statistical analysis, we analyzed the association between the Lung-RADS classification obtained and the presence or absence of malignancy in the anatomopathological examination, and obtained statistically significant results (p-value <0.0001) for this association. Discussion: The Lung-RADS system and the Fleischner Society Guidelines on pulmonary nodules are used at present. Both have similar criteria and are based on the morphological suspicion of malignancy that includes the density of the nodule (solid, partially solid or ground-glass), the size and, when available, growth or evolution, which can be applied in different groups of patients. Determining the Lung-RADS score has proven its usefulness in this study, based on the pathological correlation of the nodule, with a statistically acceptable result and a good correlation with the treatment and follow-up decision. Conclusion: The application of the Lung-RADS system to this series of patients has shown a good management of patients' follow-up, with surgical resections in some cases and an expectant approach in others, providing certain security and mostly avoiding the use of unnecessary aggressive treatments.