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tients with endophytic cancer, in whom the tumor grows intramurally, this sign gives a specific CT image of a limited or diffuse thickening of the stomach wall (□ Fig. 39) [33, 35, 53, 180].

Analysis of data in the literature, presenting quite controversial current concepts of the potentials of CT in the diagnosis of gastric cancer, shows that this problem is still pressing, and that further studies are needed. At the same time, based on our own experience and that of our colleagues with the use of CT to diagnose stomach affections in more than 300 studies, most of which were done in suspected cases of cancer and other diseases requiring differential diagnosis [31, 33, 36, 38, 47], we can state that the role of computed tomography in the examination of patients with gastric tumors is quite well defined. This will be described in detail in Chap. 5, which is dedicated to the radiological signs of gastric cancer.

Magnetic Resonance Imaging

The physical phenomenon of nuclear magnetic resonance has been known for quite some time. F. Bloch and E. Purcell were awarded the Nobel Prize for this invention in 1946, but it was introduced into practical medicine only in recent decades.

In a comparatively short time, from the early 1980s until today, MRI has become one of the most informative methods of noninvasive diagnosis. This is explained by the fact that MRI has great advantages over the other radiological diagnostic methods. Most important are its noninvasive character, the complete absence of ionizing radiation, the ability to produce multiplanar images, the unsurpassable contrast of imaging soft tissues, the natural contrast of the circulating blood, and the absence of artifacts of bone tissues and gas-containing structures [15].

Owing to continuous improvement of the method, its field of use has broadened as well. MRI is known to physicians of various profiles as a meth-

D Fig. 39a-l. Female patient S., age 68. Diagnosis; gastric cancer. a Stomach roentgenogram (tight filling, vertical position, anterior projection): additional shadow against the background of the air bubble due to intramural infiltration (arrows). b Stomach roentgenogram (double contrast, horizontal position, anterior projection): tightly filled upper part of the stomach visualizes its uneven contours (arrow); the walls of the body and the antral part are not changed. c, d Series of stomach roentgenograms (double contrast, horizontal position, left lateral projection): the upper part of the stomach body is disfigured (hourglass) due to circular intramural infiltration with the folds converging towards the focus of involvement (white arrow); the anterior wall of the upper part of the stomach is thickened and rigid (black arrow). In order to verify spread of tumor infiltration to the esophagus, the patient was examined by computed tomography of the stomach. e Computed tomography of the stomach (tight filling with E-Z-CAT DRY, supine position): the walls of the upper part of the stomach are thick due to intramural infiltration (white arrow) which spreads over onto the abdominal segment of the esophagus and the left crus of the diaphragm (black arrow). f, g, h Series of CT images (tight filling E-Z-CAT DRY, supine position): the walls are thick due to intramural infiltration. i Computed tomography of the stomach (pneu-mo-CT, prone position): stable thickening of the stomach wall is visualized over a sig-

nificantly greater length. Conclusion: Infiltrative cancer of the stomach body and its upper part with invasion of the abdominal segment of the esophagus and the left crus of the diaphragm. j Macrospecimen of a resected stomach: white tumor tissue (white arrows) infiltrating the wall; changed relief of the cardiac rosette relief can be seen (black arrow). k Fragment of a macrospecimen (strip): the stomach wall is thick due to white tumor infiltration. l Microspecimen of a fragment of the stomach wall: moderately differentiated adenocarcinoma (white arrows) with the signet-ring cell component (black arrow)

od of visualization and diagnosis of affections of the brain and spinal cord, spinal column, joints, mammary glands, thyroid gland, heart and large vessels. It is also used in the study of parenchymatous organs of the abdominal cavity and the retroperitone-al space, and the pelvic organs. It should be noted that to take advantage of all the potentials of this method, it is necessary to acquire MR tomographs with magnetic induction of a permanent magnetic field of not less than 0.35-0.5 T (Tesla). From an economic standpoint, it is more advantageous to acquire tomographs with a moderate field (0.5 T < B < 1.0 T), although »open« tomographs of 0.35 T can also be used. This is of decisive importance when conducting MRI of the abdominal organs, the stomach in particular.

The few publications by foreign authors concerning MRI of the stomach actually deal with experi-

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