Two radiologists (Y.F. and W.L.) reviewed all images independently blinded to the clinical information. Percentage of involvement in each lobe was recorded as well as the overall lung “total severity score (TSS)”. Each of the five lung lobes was assessed for percentage of the lobar involvement and classified as none (0%), minimal (1–25%), mild (26–50%), moderate (51–75%), or severe (76–100%), with corresponded score as 0, 1, 2, 3, or 4. The TSS was reached by summing the five lobe scores (range from 0 to 20) [9]. The final score of each case was decided by a third experienced thoracic radiologist (K.L.).