Table 2.

5-point scale on MRI for detection of EMVI ^a

Score	Possibility of EMVI	Imaging features
0	Definitely negative	No vessels adjacent to areas of tumor penetration
1	Probably negative	Minimal extramural stranding/nodular extension, but not in the vicinity of any vascular structure
2	Possibly negative	Stranding demonstrated in the vicinity of extramural vessels, but these are of normal caliber, and no definite tumor signal in vessel
3	Probably positive	Intermediate signal intensity apparent within vessels, although contour and caliber of these vessels is only slightly expanded
4	Definitely positive	Obvious irregular vessel contour or nodular expansion of vessel by definite tumor signal

EMVI, extramural venous invasion.

^aThe 5-point scale that was adopted for this study had been suggested by Smith et al.³