Table 1.

Subjective score criteria for image quality evaluation

Grading score	Qualitative image analysis
	Morphological display of all nodules	Visibility for surrounding lung tissue	Artifacts and diagnostic confidence
1	Very poor display, unclear edge	Unacceptable visibility, cannot distinguish small structures	Severe artifacts, insufficient confidence
2	Poor display, fuzzy edge	Small structures are not displayed very well, seriously impact diagnosis	Substantial artifacts, insufficient confidence
3	Moderate display, not very clear edge	Small structures can be displayed, and enough for diagnosis	Moderate artifacts, low confidence but diagnosis possible
4	Better display, still clear edge	Small structures can be clearly displayed with good contrast	Minor artifacts, good diagnostic confidence
5	Excellent display, clear edge	Small structures can be clearly displayed with excellent contrast	No artifacts, excellent diagnostic confidence