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Computed tomography of the abdominal cavity
Last reviewed: 05.07.2025
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Computed tomography of the abdominal cavity
All parenchymatous organs should be equally well visible. The only exceptions may be the manifestation of the private volume effect and the early arterial phase of contrast enhancement in spiral scanning. Structures such as blood vessels and intestinal loops should also be clearly visualized against the background of fatty tissue. The same applies to muscles.
You should perceive poorly visualized connective tissue spaces as a sign of edema, inflammation, or malignant neoplasm growth. If it is difficult to navigate the anatomy of the structures, then measuring the density of the area of interest or comparing sections without amplification and after the introduction of KB may help.
As before, the recommendations we offer are not strict prescriptions, but rather a useful tool for beginners. They will help reduce the likelihood of missing pathological signs.
Abdominal computed tomography technique
The abdominal cavity is also examined in the transverse direction (axial sections). The standard section thickness is 10 mm, the table advancement step is 8 mm, and the overlap of the previous section is 1 mm. In recent years, there has been a tendency to reduce the section thickness to 5–8 mm.
Abdominal computed tomography technique
Normal anatomy of the abdominal cavity
Sections of the abdominal organs cover the lower parts of the lungs, which continue to be visualized in the caudal direction in the posterior and lateral costophrenic sinuses. In the venous phase of contrast enhancement, the parenchyma of the liver and spleen usually has a homogeneous structure without focal changes. Only the branches of the portal vein and the round ligament can be seen. To assess the walls of the stomach, before the examination, the patient is given intravenous buscopan and a low-concentration KB solution to drink. 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 section passes in an oblique or perpendicular direction, the dome of the diaphragm can be seen as a thin structure.
CT scan of the abdomen is normal
Abdominal wall pathology
Pathological formations of the abdominal wall are most often localized in the groin area. Lymph nodes enlarged to 2 cm in diameter should not be considered pathologically changed. Large conglomerates of lymph nodes are characteristic of non-Hodgkin's lymphoma and are less common in lymphogranulomatosis (Hodgkin's disease).
Abdominal wall pathology on computed tomography
When planning a liver biopsy or radiation therapy, it is necessary to know exactly in which segment the pathological formation is located. Along the main branch of the portal vein in the horizontal direction, the liver is divided into cranial and caudal parts. In the cranial part, the borders of the segments are the main hepatic veins. The border between the right and left lobes of the liver does not pass along the falciform ligament, but along the plane between the middle hepatic vein and the gallbladder fossa.
Computed tomography of the liver
After the creation of a choledochoenteroanastomosis, sphincterotomy or endoscopic retrograde cholangiopancreatography (ERCP), hypodense air bubbles usually appear in the lumen of the intrahepatic bile ducts. Such presence of air should always be differentiated from gas due to the development of an abscess in anaerobic infection.
Computed tomography of the gallbladder
Computed tomography of the spleen
The parenchyma of the spleen on native images during computed tomography of the spleen normally has a density of about 45 HU. Its structure is homogeneous only on native images and in the late venous phase of contrast enhancement.
Computed tomography of the spleen
Computed tomography of the pancreas
Acute pancreatitis may manifest itself as acute interstitial edema of the pancreas. In this case, the pancreas is visualized with unclear contours, without the cellular structure typical for it in the norm. Hypodense fluid (exudate) and edema of the connective tissue are often determined near the pancreas. As the destructive process spreads, hemorrhagic pancreatitis and pancreatic necrosis develop, which is a poor prognostic sign.
Computed tomography of the pancreas
Computed tomography of the adrenal glands
The maximum length of the adrenal glands is 2.1 - 2.7 cm, the right one is often longer than the left. The thickness of the branches should not exceed 5 - 8 mm in cross section. Fusiform or nodular thickening of the adrenal gland and inferior vena cava.
Computed tomography of the adrenal glands
Computed tomography of the kidneys
The density of the renal parenchyma on native images is about 30 HU. The sizes of the kidneys are quite variable. If the outer contour of the kidney is smooth and the parenchyma is uniformly thinned, unilateral renal hypoplasia is likely. A reduced kidney is not necessarily a diseased kidney.
Computed tomography of the kidneys
Computed tomography of the bladder
The bladder wall is best examined with the bladder filled. If a urinary catheter is inserted and sterile water is injected into the bladder before the CT scan, it will act as a low-density contrast agent. In this case, local or diffuse trabecular thickening of the bladder wall associated with prostatic hyperplasia will be clearly visible. If a stent is inserted into the ureter for a stricture or retroperitoneal neoplasm, the distal end of the JJ stent may be visible in the lumen of the bladder.
Computed tomography of the bladder
Computed tomography of the stomach and intestines
To examine the stomach after intravenous administration of buscopan, the patient is given water to drink as a hypodense contrast agent. However, a small tumor may not be seen with traditional CT scanning. Therefore, in addition to CT, it is necessary to conduct an endoscopic examination and endosonography.
Computed tomography of the stomach and intestines
Computed tomography of the retroperitoneal space
Ectasia or aneurysms of the abdominal aorta usually develop as a result of atherosclerosis. They are often accompanied by mural thrombus formation. The abdominal aorta is considered aneurysmally altered when the expansion of the free lumen of the vessel reaches 3 cm or the external diameter exceeds 4 cm. In asymptomatic patients, surgical intervention is usually justified if the aneurysm diameter reaches 5 cm. The patient's general condition and the rate of expansion are assessed. The risk of aneurysm rupture with bleeding is reduced if the free lumen of the vessel is located centrally, and thrombotic masses surround it more or less evenly from all sides.
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