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The hip joint is responsible for flexion/extension, abduction/adduction, pronation/supination of the hip. Also, thanks to him, a person can carry out a circular rotation of the hip. A joint can be affected by a variety of diseases, ranging from standard trauma to rare bone cancers. Computed tomography is used for informative and fast diagnostics. How does the method differ from radiography, in what cases is tomography indicated and what to expect from the study?
How a CT scanner works
Computed tomography, like x-rays, uses x-rays for diagnostic purposes. A modern tomograph is a whole software and hardware complex. It consists of mechanical components, ultra-sensitive detectors, X-ray emitters, various components and software that analyzes and visualizes images. The principle itself is based on the heterogeneity of X-ray absorption by the tissues of a living organism, which depends on the location of the tissue, its specificity, density and other characteristics.
The device records the degree of absorption of rays, transmits information to a computer that analyzes it and forms an image of the diagnosed area. The equipment creates a three-dimensional image of the internal cavity/bones/vessels from a set of step-by-step cuts. The doctor analyzes it, notes violations and pathologies, develops an individual therapeutic course.
CT equipment receives slices of objects, the thickness of which is 0,05 millimeters. This indicates a high speed and diagnostic accuracy of scanning. Like any other diagnostic method based on X-rays, tomography distinguishes between skin, fat, air, water and soft tissues. The greatest difficulties arise with the study of soft tissues – the picture may not be clear enough, and therefore uninformative. To correct the situation, radiopaque agents are used. If the use of contrast is not possible, then the patient may be prescribed additional diagnostics (for example, ultrasound).
What you need to know about the use of contrast in a CT scan?
The radiopaque agent helps to “separate” organs and tissues from each other, visualize them more clearly, and remove additional interference that affects the evaluation of results. The main component of the contrast is iodine. The drug is administered orally and distributed through the gastrointestinal tract or intradermally through the bloodstream. The areas on which the iodine-containing preparation falls are literally “highlighted” and become more visible. With the help of contrast, a radiologist can easily determine pathological changes in an organ, study the blood flow of cancerous tumors, or evaluate vascular function.
The contrast agent is absolutely safe for the human body and is excreted naturally through the kidneys. The use of contrast has contraindications – individual intolerance to the drug and severe kidney disease. In the first case, there is a high risk of developing allergic reactions, in the second – difficulties in removing the drug from the body.
| Показания | Противопоказания |
|---|---|
| Infectious / inflammatory processes in the articular tissues | Pregnancy (due to the harmful effects of radiation exposure on the fetus) |
| Diagnosis of congenital anomalies of development or damage after mechanical injuries | Claustrophobia, various mental disorders (the patient will not be able to maintain a fixed position, and stress can cause a number of complications of an existing illness) |
| Arthrosis with thinning of cartilage | Excess body weight that exceeds the maximum allowable weight for CT equipment (most devices are designed for patients up to 200 kilograms) |
| Arthritis (inflammation of the joint) | Age up to 14 years |
| Air cavities in bones, cysts | Individual intolerance to iodine-containing drugs, thyroid pathology, diabetes mellitus, renal failure (during the passage of contrast tomography) |
| Cancerous neoplasms, regardless of nature | |
| Aseptic necrosis of the femoral head | |
| Osteomyelitis in combination with purulent formations | |
| General diagnosis of the hip joint before or after surgery | |
| Evaluation of the dynamics of various pathologies, determining the effectiveness or the formation of treatment tactics |
Preparation for research
Specific preparation is needed only when conducting contrast diagnostics. The patient must refrain from eating 6 hours before the CT scan. This is necessary to minimize side effects. Moreover, the contrast agent will spread faster and more efficiently through the “clean” gastrointestinal tract. In addition to not eating, the patient should choose comfortable and safe clothing. It should be simple pants / T-shirt made of natural or synthetic fabric without metallic decor elements. Metal particles can distort the image, leaving blank white spots in the final XNUMXD image.
CT procedure
The patient independently or with the help of a medical worker is located on a movable table. The scanning ring is placed directly over the hip joint, a brief briefing is given. The medical officer records the scan results and remotely monitors the patient’s condition. The scanning ring sends X-rays to the hip joint, and ultra-sensitive sensors record the degree of their absorption by the tissues. Then the information is transferred to a computer, where it is converted into a three-dimensional image of the scanned area using special algorithms.
It is important to remain completely still during the scan. Even defects in one or two scans will affect the final result and reduce the accuracy of the study. If necessary, you can fix the limbs with special soft straps. The rest of the body (besides the scanned hip joint) is covered with a special apron that reflects X-rays. The duration of the procedure is about 5 minutes. When conducting contrast tomography, the time frame is extended to 20 minutes.
Contrast is used when it is necessary to more clearly visualize the soft tissues and vessels surrounding the hip joint. An iodine-containing drug is administered intravenously immediately before the scan. The contrast quickly enters the vessels through the bloodstream and spreads throughout the body. Possible side effects from using contrast are nausea, vomiting, and dizziness. If the patient feels a rapid deterioration in the condition, then the study is interrupted until the nature of the reaction is clarified.
It is the contrast that poses the main danger when performing tomography. The substance may cause adverse symptoms even in people who are not allergic to its constituents. The risk of side effects is 3-4%.
Alternative Research Methods
The hip joint is the largest joint in the human body. Large size opens up a lot of methods for diagnosis. If for some reason computed tomography is undesirable or unavailable, then conventional x-rays can be used. It remarkably visualizes bone tissue, reveals arthritis / arthrosis / various foreign bodies. To diagnose fractures, injuries and cracks, doctors recommend an ultrasound examination.
To assess the condition of soft tissues and diseases that may be associated with them, magnetic resonance imaging is prescribed. The method is considered the safest for the body, since it is based on the effect of a magnetic field. With the help of MRI, the anatomical features of the muscular apparatus, cartilage, ligaments, blood vessels and joint capsule are revealed. Alternatively, arthroscopy can be used. This is an invasive technique that involves the insertion of a microcamera inside the joint and is often used for biopsy of biological material or for surgical procedures.
The choice of diagnostic method always remains with the doctor, who evaluates the general condition of the patient’s body and chooses the most effective and safe study. Strictly follow the medical instructions and be healthy.