Throughout the years, pulmonary diseases have caught the attention of researchers from all over the globe, over all for its tricky characteristics and challenging diagnostic. During the COVID-19 pandemic, lung scanning gadgets and auxiliary technologies importance has been spotlighted, specially when it comes to image contrast evaluation, which has shown to be a key diagnostic criterion. Many contrast evaluation metrics have been developed aiming to improve analysis for this important parameter, either globally, analyzing contrast on the whole image, or locally, focusing on specific regions of interest. The present study examines the Carneiro Contrast Index (CCI), a global contrast metric, using the Measurement of Enhancement (EME), a local contrast metric, as a landmark. The main findings suggest that CCI and EME appliance on different lung pathologies x-ray images converge to the same numerical outcome, substantiating the Carneiro Contrast Index as a reliable and replicabe tool for chest x-ray assessment.