Magnetic Resonance Signs

There are two reasons for including MRI in the sections of this book describing our understanding of current methodological-semiotic possibilities of radiological diagnosis of gastric cancer. First, MRI of the stomach is now acknowledged as a common method for diagnosing gastric pathology in general and gastric cancer in particular. Second, recent publications imply that endoscopy is the foundation on which the characteristics of MRI of the stomach are based; the results of modern traditional radiology with tight filling and double contrast are completely disregarded. This approach inevitably interferes with a complete and objective estimation of the diagnostic role of MRI of the stomach.

In addition to endoscopic findings, while looking at the possibilities of MRI, we took the results of traditional X-ray examinations with double contrast and subsequent comparative studies of MRI, anatomical, and surgical data as the basic initial data. We used these basic data to study MRI signs of gastric cancer, which we will now discuss.

In order to evaluate the condition of the stomach wall and the basic MRI criteria of affection, the MRI characteristics of an intact stomach (without signs of pathology) were first established. As the stomach cavity is distended with water, the stomach contents are shown on a T1 image by the low-intensity signal; on a T2 image it is bright due to the long Ti and T2 of water. On a Ti image, the stomach wall at optimal distension is not visualized except in the zone of the gastroesophageal junction, the antero-posterior size of which does not exceed 10 mm (D Fig. 88). Visualization of the wall on a Ti image is always connected with tumor or inflammatory infiltration (D Fig. 89) [14, 111, 220, 235].

On a T2 image, the wall thickness at the level of the stomach body (anterior and posterior walls and the lesser curvature) is 2-4 mm; on the greater curvature and in the sinus region it is 3-4 mm, due to the specific character of the mucosal relief and the higher tone of the circular fibers of smooth muscles of the greater curvature compared with the other parts of the stomach. The signal from the intact stomach wall is homogeneous and has moderate intensity (D Fig. 90). The inner configuration of the wall may be somewhat uneven, as if serrated, due to incompletely stretched mucosal folds. The outer contours are distinct, excepting those of the greater curvature in the lower third of the stomach and its sinus. As on a TI image, the thickness of the gastroesophageal junction is 10 mm, signal intensity is lower than that from the stomach walls over the other parts, or identical to it. This is because of the large volume of muscle tissue in this zone, and because natural distension of the esophageal and stomach walls in this region is viewed in the oblique plane of scanning in the axial projection [136, 159].

▲ Fig. 88. MRI of an intact stomach body on a T1 image: the wall is not visualized.
Stomach Cancer Mri

D Fig. 89. Patient M., age 67. Diagnosis: gastric cancer. MRI of the stomach on a T1 image: uneven thickening of the anterior wall (1) and posterior wall (2) to 12 mm. The MR signal from the affected wall is heterogeneous, mostly of moderate intensity (arrows). The patient was operated. Histologically, adenocarcinoma

▲ Fig. 91. MRI of the pyloric part of the intact stomach on a T2 image: a distinct hypointense, uniform 1.5-mm stripe is seen along the posterior wall - the reflection of the serous membrane (arrow)

□ Fig. 92a-e. Female patient R., age 63. Diagnosis: gastric cancer. a Stomach roentgenogram (tight filling, vertical position, anterior projection): the distal part of the stomach is strongly disfigured, pulled upwards due to massive circular infiltration (arrow). b Stomach roentgenogram (double contrast, horizontal position, right halfoblique projection): walls of the antral part and the lower third of the stomach body are thickened and rigid due to intramural infiltration, invading the stomach body (arrows). Conclusion: Infiltrative cancer of the antral part and the body of the stomach. c MRI (stomach filled with water, axial projection, level of the pyloric part of the stomach, T2 image): the border between the infiltrative tumor of the stomach and the pancreas head is not detectable (arrows). d MRI of the stomach (stomach filled with water, sagittal projection, level of the pyloric part of the stomach, T2 image): distinctly visualized is the border between the infiltrated tumor of the stomach wall and the pancreas head (arrow). e Fragment of a macrospecimen (strip): stomach wall is thickened over a considerable length due to white intramural infiltration into the muscular coat (arrows). Histologically; signet-ring cell carcinoma with extracellular accumulation of mucus

Was this article helpful?

0 0
Virtual Gastric Banding

Virtual Gastric Banding

Virtual Gastric Band Hypnosis Audio Programm that teaches your mind to use only the right amount of food to keep you slim. The Virtual Gastric Band is applied using mind management techniques, giving you the experience of undergoing surgery to install a virtual gastric band or virtual lap-band, creating a small pouch at the top of the stomach which limits how much food can be eaten. Once installed, the Virtual Gastric Band creates the sensation of having a smaller stomach that is easily filled and satisfied with smaller amounts of food.

Get My Free Audio Book

Post a comment