CT (computed tomography) of the kidneys with contrast


The kidneys are vital organs, and even a slight decrease in their function leads to deterioration of health of the human body. When you develop a serious diseases of the urinary system, quality of life suffers significantly.

Currently, there are highly effective methods of diagnosis of kidney disease early, allowing time to begin treatment and maintain the health of organs. One such method is computer tomography.

The principle of action of the method

CT diagnoses with the use of x-rays. The x-ray beam emitted from the detectors on the inner surface of the ring tomograph, around the human body in a spiral, performing a detailed scanning of the tissue and making images every few millimeters. Therefore, the method and received the name of spiral computed tomography. The result is a detailed three-dimensional picture of the state of organs and systems.

Scanners are advancing rapidly and are now widely used multislice computed tomography, which has several rows of detectors, allowing to scan even the whole body in one revolution of the x-ray tube. It helps to increase the efficiency of diagnosis and significantly reduce the time for the procedure.

For a long time a CT scanner is much inferior to MRI in visualizing soft tissues. Now modern spiral machines allow us to diagnose the pathology of internal organs almost on the same level with MRI.

Significantly improves the quality of diagnostic use contrast agents, therefore, modern research is almost always carried out with contrast. For computed tomography of the kidneys use water-soluble radiopaque substances containing iodine.

How is the study?

During the study, the patient is placed supine on the table, which is part of the apparatus. The table is equipped with cushions for the head and straps that will help to fix the correct position of the patient.

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Around the table rotates the ring setting, emitting x-rays and fixing the degree of absorption of their tissue, it is called the gantry. The inner diameter of the ring can vary from seventy to ninety centimeters, which allows to examine patients.

The study is non-invasive and painless, lasts about fifteen minutes. Initially, the native scan (conventional) method, then injected the contrast. For diagnostics of kidney diseases contrast agent administration is performed intravenously in a vein of the elbow (if the elbow is not available, in the vein of other sites).

Introduction of contrast medium may occur manually, for that, the radiologist will turn off the machine and a nurse will inject the drug with a syringe. Some modern devices allow introduction automatically, using a special installation of the injector.

What renal pathology lets see SKT?

Kidney CT can be performed as part of the examination of the abdominal organs. Also your doctor may prescribe a CT scan of the kidneys alone of the abdominal cavity in cases of suspected pathology of the retroperitoneal region.

Pathological processes of the kidney, diagnosed using CT with contrast:

  • Of the cyst. Cystic masses in the kidney (a rounded cavity with liquid content inside) can be single or multiple (polycystic kidney disease). Both conditions require special attention: in the first case requires differential diagnostics with cavernous form of cancer of the kidney, the second is a severe congenital disorder that requires close monitoring of the patient.

  • Cancer treatment processes: the size, the shape of the tumor. Modern CT devices allow us to determine the malignancy of the tumor and its structure. You can set the spread (metastasis) of the cancer process beyond the kidney: retroperitoneal space and abdominal cavity, lymph nodes.
  • Injury. As a result of trauma may develop a hematoma within the renal tissue and in adipose tissue beside her, severe injuries may even be rupture of the capsule of the kidney. All changes of the visualizations available with the help of CT.
  • Purulent processes. Abscess and carbuncle of the kidney can be detected at CT and to differentiate them from single cysts.
  • Tumors of the adrenal glands. The adrenal glands important endocrine glands that play an important role in the hormonal state of the human body. They lie on the upper poles of the kidneys and the available CT diagnosis along with the examination of the kidneys and abdominal organs.
  • Nephroptosis – the omission of the kidney. The disease can have three degrees and is characterized by the prolapse of the kidney to the pelvic area that causes a disturbance of its functions.
  • Stones. Computed tomography, among all the diagnostic methods, has the highest sensitivity and specificity for determination of renal calculi, as it allows to detect the degree of blockage of the ureter and to differentiate the disease from other pathological processes, for example, from the abdominal cavity.
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  • Congenital anomalies. Usually detected accidentally during abdominal CT. The most striking of these are the doubling of the kidneys, as well as the only or primary wrinkled kidney.

In addition to this pathology, a CT scan of the kidney can be prescribed by a doctor to determine where a needle biopsy of the pathological focus, sometimes the procedure is performed intraoperatively. Also need the procedure after the amputation, kidney is to ensure that no hematoma in the renal bed. The study was conducted in organ transplantation, to evaluate its viability.


Computed tomography refers to methods of radiation diagnosis, and, despite the fact that modern devices allow to make the radiation exposure is minimal, it is absolutely contraindicated the use of CT in pregnant and lactating women and also undesirable young children. Will not be able to perform the procedure, the patient, if the volume of its body is equal to or greater than the diameter of the ring gantry.

Contraindications for administration of contrast media are:

  • Allergic reactions to iodine and other components of contrast agents.
  • Diseases of the thyroid gland.
  • Severe diabetes.

  • Acute and chronic renal failure.
  • Multiple myeloma.

How to prepare for the exam?

Topographically the kidneys are behind the abdomen (gastrointestinal), in the retroperitoneal space, sometimes the abdominal organs can complicate diagnosis. Therefore preparation for the CT is to refrain from eating for three days foods that help you poop in the intestines: bread and bakery products, carbonated beverages, fruit and vegetables, dairy products.

The preparation lies in the fact that immediately before the study with contrast should come on an empty stomach, if CT is performed in the first half of the day, or not eating for five hours before KT in the afternoon. Another preparation computed tomography is not required.