Table 3 Evaluation criterion of imaging quality

5 (Excellent)

Clear display of vessels and their branches (complete and continuous); clear display of lymph nodes (quantity and distribution)

4 (Good)

Between grade 5 and grade 3

3 (General)

Partially display of vessels and branches (lost beginning or ending or display segmentally); partially display of lymph nodes

2 (Medium)

Between grade 3 and grade 1

1 (Poor)

Not display vessels and lymph nodes, affected by noise seriously