Table 1.

The scoring system of computed tomography (CT) for the assessment of the extent of Mycobacterium abscessus complex lung disease

CT findings	Score 0	Score1	Score 2	Score 3
Bronchiectasis (6 points)
Severitya	Absent	Mild	Moderate	Severe
Lesion extensionc	Absent	1–5	6–9	> 9
Cellular bronchiolitis (6 points)
Severityb	Absent	Mild	Moderate	Severe
Lesion extensionc	Absent	1–5	6–9	> 9
Cavitation (6 points)
Diameter (cm)d	Absent	< 3	3–5	> 5
Lesion extensionc	Absent	1–2	3–4	> 4
Consolidation (3 points)c	Absent	1–3	4–5	> 5
Nodules (3 points)c	Absent	1–2	3–4	> 4

^aMild = bronchus diameter is around 1.5–2 times that of adjacent vessel; moderate = bronchus diameter 2–3 times vessel diameter; severe = bronchus diameter > three times vessel diameter

^bMild = identifiable, peripheral lung, 1 cm from pleura; moderate = definite, involvement greater than 1–3 cm from pleura; severe = extensive, extending to central lung

^cInvolvement of each of the six lobes was estimated as follows: 0, no involvement; 1, involving less than 33.3% of the total number of segments in the lobe; 2, involving 33.4–66.6% of the total number of segments in the lobe; 3, involving greater than 66.7% of the total number of segments in the lobe. Total score ranges from 0 to 18 (each lobe has a maximum score of three and there are total of six lobes)

^dThe largest cavitation is evaluated, and the largest outer diameter (cm) is recorded as follows: 0 for no cavitation, 1 for outer diameter < 3 cm, 2 for outer diameter ≥ 3 cm and ≤ 5 cm, and 3 for outer diameter > 5 cm