Table 1.

Criteria for Scoring Image Quality and Delineation of Anatomic Structures

Score	Overall quality	Lungs	Pulmonary arteries	Airways
5	Excellent; high SNR; answers all clinical questions	Clearly distinguishable from air; fissures visible	No appreciable blurring of structures	Lower signal and clearly distinguishable from nearby lung; bronchial wall visible
4	Good; high SNR; more than sufficient for the majority of clinical questions	Clearly distinguishable from air; fissures not visible	Slight blurring of structures	Lower signal and clearly distinguishable from nearby lung; bronchial wall not visible
3	Adequate (moderate); sufficient for the most important clinical questions	Distinguishable from air; fissures not visible	Distinguishable with moderate blurring of structures	Lower signal and distinguishable from nearby lung; bronchial wall not visible
2	Limited (poor); barely sufficient for assessing some clinical questions	Barely distinguishable from air; fissures not visible	Barely distinguishable with extensive blurring of structures	Lower signal but barely distinguishable from nearby lung; bronchial wall not visible
1	Nondiagnostic; not clinically useful	Indistinguishable from air; fissures not visible	Not distinguishable	Indistinguishable from nearby lung

SNR = signal-to-noise ratio