Radiographic examination of gastric cancer

Since gastric cancer lacks specific symptoms and signs, statistics show that the detection rate of early gastric cancer in my country is less than 10%. It should be emphasized that barium meal and gastroscopy should be used as a routine examination method, which has extremely important clinical significance for the diagnosis of gastric cancer (especially the diagnosis of early gastric cancer).

1. Barium meal examination Barium meal examination is the main method for diagnosing mid- to late-stage gastric cancer. Low-tension double contrast examination technology helps to detect early gastric cancer. The characteristics of gastric cancer at each stage are as follows:

(1) Early gastric cancer: The filling compression image of the protruding type early gastric cancer is observed from the front as a round, oval or flower-shaped tumor of varying sizes, with clear edges and rough contours. The frontal view of the depressed type early gastric cancer shows round, oval, granular and irregular barium spots of varying sizes, with sawtooth or needle-shaped edges, rough and uneven. The barium deposits in the depressed lesions are thicker and have a higher density. The superficial flat type early gastric cancer is difficult to diagnose because the lesions are flat.

(2) Advanced gastric cancer: ① Filling defect in the gastric cavity, incomplete edge contour of the defect. ② Niche shadow in the cavity: the niche shadow is large and shallow, mostly surrounded by a wide translucent band, called the "ring embankment sign". ③ Localized destruction, interruption, and rigidity of the mucosa. ④ Changes in gastric contour: the gastric cavity is deformed, the gastric wall is rigid, peristalsis disappears, and the gastric volume is small and fixed.

2. CT scan shows irregular soft tissue masses protruding into the cavity, limited or diffuse thickening of the stomach wall, and the wall is not smooth. Enhanced scan shows uneven enhancement of the lesion, with no obvious boundary with the normal stomach wall. The tumor grows outside the stomach, the perigastric fat layer disappears, and the surrounding organs can be invaded. Round enlarged lymph nodes can be seen in the retroperitoneal space and abdominal cavity, and hematogenous metastatic lesions of the liver and spleen can be seen.

3. MRI examination The MRI manifestation of gastric cancer is related to its stage, type, and whether there is invasion of surrounding organs and lymph node metastasis. Early gastric cancer has no obvious specific changes due to the thickness of the portal wall. The MRI manifestations of advanced gastric cancer are medium or slightly low signal in TIW1 and medium high signal in T2W1. The enhanced scan shows uneven moderate enhancement of the lesion, thickening of the gastric wall in the lesion area, unclear boundary with the normal gastric wall, and niche shadows in the wall. The advantage of MRI is to understand the extragastric infiltration and abdominal lymph node enlargement, which is conducive to the correct staging of gastric cancer before surgery and the formulation of a reasonable treatment plan.