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Computed tomography of the abdominal cavity is normal
Last reviewed: 23.04.2024
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Normal anatomy
Sections of the abdominal cavity organs capture the lower parts of the lungs, which continue to be visualized in the caudal direction in the posterior and lateral costo-diaphragmatic sinuses. In the venous phase of contrast enhancement, the parenchyma of the liver and spleen usually has a homogeneous structure without focal changes. One can only notice the branches of the portal vein and the round ligament. To assess the walls of the stomach before the study, the patient is injected with a buscopan and given a low concentration KB solution. The diaphragm, located between the thoracic and abdominal cavities, merges with the liver and spleen due to their equal density. If its section on the cut passes in oblique or perpendicular direction, then the dome of the diaphragm can be seen as a thin structure.
The pancreas usually has a distinctly prominent parenchyma and an uneven contour. The head and hook-shaped process of the pancreas descend quite far in the caudal direction. The left adrenal gland often has a Y-shaped shape, while the right adrenal gland is a sagittal or a comma. Pay attention to the mouth of the celiac trunk and the superior mesenteric artery leaving the abdominal aorta. In this area, you can often see enlarged lymph nodes.
Near the gallbladder you can sometimes see the effect of a private volume due to the ascending colon. Normally, its walls are thin and clearly delineated, unlike the root of the mesentery of the small intestine. The duodenum is different from other loops of the small intestine only by its location. At this level, you should make sure that the edges of the kidneys are even and there is no wrinkling of the parenchyma. Fatty tissue allows you to more clearly visualize the straight and oblique abdominal muscles in the abdominal wall.
After aortic bifurcation (usually at the level of the L4 vertebra), the common iliac arteries are located in front of the corresponding veins. Still lateral on the anterior surface of the lumbar muscles are both ureters. Together with the iliac bones, the middle gluteus muscles are visualized, in which there are sometimes areas of calcifications after intramuscular injections.
The ureters pass from behind and approach laterally to the base of the bladder. Inside the bladder, areas of different concentrations of urinary excreted KB are determined, which causes a boundary between fluids of different densities. The next page shows the sections of the man's small pelvis. Pay attention to the prostate gland, seminal vesicles, the seminal cord and the root of the penis. Internal muscles and muscles that lift the anus are located on the sides of the anus. CT images of the male pelvis are more caudal compared to the female pelvis.
Variants of normal anatomy
It is important for beginners to familiarize themselves with the most common variants of normal anatomy, which can be the cause of errors in reading CT images. In some patients, the edge of the right lobe of the liver looks scalloped because of the depressions of the diaphragm, which should not be taken for abnormal liver formation. The walls of the unfilled stomach are thick and resemble a malignant neoplasm.
With ultrasound, you can make a mistake by taking an abnormal left renal vein for retroaortic lymph nodes. Usually, the left renal vein passes between the superior mesenteric artery and the aorta. However, this vein can be located behind the aorta and can be directed to the inferior vena cava between the aorta and the spine. Also, there is often a doubling of the left renal vein, when one branch passes in front of the aorta, and the other - behind the aorta.
Manifestations of the effect of a private volume
If the wall of one organ is pressed into the other, on an image in the cross section it looks as if one organ is located inside the other. For example, the sigmoid colon may appear "inside" the bladder. Comparison of neighboring slices shows that only parts of these organs are represented in the image. A similar pattern occurs when the right bend (hepatic angle) of the large intestine is defined "inside" the gallbladder.
Anatomy of the female pelvis
In the female pelvis, the size of the uterus and its location relative to the bladder vary considerably. The uterus can be located on the top or side of the bladder. The cervix and vagina are between the bladder and rectum, while the ovaries are seen laterally. Depending on the age and phase of the menstrual cycle in the ovaries, follicles can be identified, which can be mistaken for cystic formations).
Free fluid in the abdominal cavity (with ascites or bleeding) can be detected in the rectal-uterine cavity between the rectum and the uterus, as well as in the vesicouter space. Normally, lymph nodes in the inguinal region can reach a diameter of 2 cm). The size of normal lymph nodes of the abdominal cavity usually does not exceed 1 cm. Hip joints can not be examined in a soft tissue window. The head of the femur in the acetabulum is best analyzed in the bone window (not shown here). Evaluation of structures in the bone window completes the examination of the abdominal cavity and pelvis.
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