Serial Chest Radiographic Score
The extent of pneumonia in the SARS patients with longitudinal follow-up is assessed by a radiologist according to a serial chest radiographic score, modified from a score system initially proposed to assess computer tomography of the chest (16) and summarized as in Fig. 2.
Fig. 2. Assessing the extent of pneumonia by chest X-ray opacity score. The opacity in each zone (apex+upper, middle, and lower zones) from the left and right regions of the lung was scored by a “coarse semiquantitative method” with a 5 points’ scale of grades 0–4 representing involved areas of 0, 5–24, 25–49, 50–74, and 75–100%, respectively. A total score was then calculated by adding up all the grades in the six zones (Apex and upper zones were considered as one zone) to provide a 0–24 points’ scale with the higher number representing more severe pneumonic disease.
After X-ray chest radiography is taken, divide the frontal chest X-ray radiograph into six lung zones, namely, left upper zone, left middle zone, left lower zone, right upper zone, right middle zone, and right lower zone.
The upper zone (left or right) represents area above carina (including the apex).
The middle zone (left or right) represents area from carina to the level of inferior pulmonary veins.
The lower zone (left or right) represents area from the lower margin of middle zone to the lung base.
Score the opacity in each lung zone by a “coarse semiquantitative method” with a five points’ scale of grades 0–4.
Grade 0 represents no opacity involved area.
Grade 1 represents 5–24% opacity involved areas.
Grade 2 represents 25–49% opacity involved areas.
Grade 3 represents 50–74% opacity involved areas.
Grade 4 represents 75–100% opacity involved areas.
Add the grading from each of the six lung zones to provide a 0–24 point summation scale for assessing the extent of pneumonia.