STAGE (depth of invasion)

New MDCT criteria

T1a (mucosa)

Tumor shows enhancement and/or thickening of the inner mucosal layer, as compared to the adjacent normal mucosal layer, with an intact low-density-stripe layer.

T1b (submucosa)

Disruption of the low-density-stripe layer (less than 50% of the thickness) is visualized.

T2 (muscolaris propria)

Disruption of the low-density-stripe layer (greater than 50% of the thickness) is visualized without abutting on the outer, slightly high-attenuating layer.

T3 (subserosa)

Discrimination between the enhancing gastric lesion and the outer layer is visually impossible, and a smooth outer margin of the outer layer or a few small linear strandings in the perigastric fat plane are visualized.

T4a (serosa)

An irregular or nodular outer margin of the outer layer and/or a dense band-like perigastric fat infiltration is visualized.

T4b (adjacent organs)

Obliteration of the fat plane between the gastric lesion and the adjacent organs or direct invasion of the adjacent organs.