Pulmonary emphysema is an abnormal permanent enlargement of the airspaces distal to the terminal bronchioles, accompanied by destruction of the alveolar wall and without obvious fibrosis.

Pulmonary emphysema is part of the chronic obstructive pulmonary disease (COPD) spectrum and encompasses a number of entities and morphological patterns, of which the most important subtypes are centrilobular (most common), panlobular and paraseptal.

Epidemiologically speaking, approximately 210 million people are affected worldwide, leading to 3 million annual deaths, total. It is predominantly a disease of middle to late life owing to the cumulative effect of smoking and other environmental risk factors.  The incidence is now equal between both genders. Patients with genetic risk factors such as alpha-1-antitrypsin deficiency (AAT) may present earlier, according to phenotype.

Risk factors include smoking (most common by far), asthma (the combination with smoking greatly increases the risk),  AAT deficiency and intravenous injection of methylphenidate (the so-called Ritalin lung).

Emphysema can be graded quantitatively and qualitatively.

The former, called the emphysema index, is assessed using specific computer software, which automatically detects lung contours and plots histograms to determine the lung attenuation values, allowing the calculation of the relative percentage of pulmonary area occupied by pixels with attenuation values lower than 950 Hounsfield Units (HU).

The latter regards the pattern of emphysema's distribution in the lung and can be graded by objective, semi-objective and subjective (visual scoring) methods.

This poster focus on a subjective method, easily applicable on any Radiology Department with access to a CT scan.