Fig. 1—

Three patients with rectal cancer, two of whom also had MRI-detected extramural venous invasion (EMVI), with corresponding pathologic results.

A, 68-year-old man with rectal cancer and MRI EMVI score of 0 (definitely absent) and negative EMVI at histopathologic examination. No definite extramural tumor extension is observed on T2-weighted oblique axial MR image. Normal-caliber perirectal vessels of low signal intensity are shown (arrowheads).

B, 61-year-old man with rectal cancer and MRI EMVI score of 2 (indeterminate) with positive EMVI at histopathologic examination. T2-weighted oblique axial MR image shows suspicious extramural tumor stranding (arrow) in vicinity of extramural vessels (arrowheads). However, tumor signal intensity does not extend to these normal-caliber perirectal vessels of low signal intensity. Note there is indeterminate perirectal lymph node (line), which was pathologically confirmed as regional lymph node metastasis.

C and D, 44-year-old woman with rectal cancer and MRI EMVI score of 4 (definitely present) with positive EMVI at histopathologic examination. T2-weighted oblique axial MR image (C) shows intermediate tumor signal with serpiginous extension (arrow) along vascular structure (arrowheads). On sagittal MR image (D), irregular tumor signal (arrow) extends cranially from primary rectal cancer along vein of low signal intensity (arrowheads).