It’s a high-precision diagnostic procedure enabling a doctor to diagnose initial stage of pathological process in the human organism. Moreover, MRI gives a complete idea of the pathological process: its location, sizes, spread and even origin. A pathological process in the central nervous system can be inflammatory, demyelinating (sclerotic focuses), can be result of the trauma, vascular system failure or tumor. Method accuracy is proven by the fact that with its help even the slightest up to 1 mm pathological focuses can be reviled. For examination a man should be placed in a special device creating a constant magnetic field. Method’s accuracy depends on field force. To get more accurate results and diagnose focuses which require intensifying patholocical objects, a patient is injected contrast substance. It improves tomographic scanner diagnostic precision and enables seeing the slightest focul processes.
Questions and Answers
Magnetic resonance imaging (МRI) is used for examining central nervous system, namely brain and spinal cord, and detecting focuses of vascular, sclerotic, infectious nature in nerve tissue, locomotorium, soft tissues, endocrine glands, pelvic organs of males and females.
Generally no preparation is required for МR examination. If brain or spinal cord, cervical, breast or lumbar spine, soft tissues or large joints are to be examined, one can eat, drink or take medicine.
Price does not have anything to do with procedure quality or safety or doctor’s qualification. The following factors influence examination cost: а) device technical capacity, production date, operation time, etc; b) location of the medical center (difference in the price for rent downtown and at the outskirts of the city); c) possibility of getting extra consulting in a medical center.
To get an image using computer tomographic scanner X-rays are used. A computer tomographic scanner has a special X-ray tube rotating around patient’s body and taking images at different angles. Then images are processed by computer. To get an image using magnetic resonance imaging scanner X-rays are not required. A patient is placed in a powerful magnetic field. In this case all hydrogen atoms in the patient’s body are placed inparallel to magnetic field direction. The device sends an electric frequency sigal perpendicular to the main magnetic field. Hydrogen atoms having frequency the same as the signal’s one, get “excited” and generate their signal that is detected. Different types of tissues (bones, muscles, vessels, etc.) have different amount of hydrogen atoms, thus generating signals with different features. The tomographic scanner receives and deciphers these signals and creates images.
If one looks at a regular X-ray film, even if he/she does not have special medical knowledge, he/she will be able to see different bones. CT uses X-rays, thus it can "see" bones structures and parenchymal organs better. That’s why CT is an ideal device for diagnosing bone damages and traumas. It is also good to detect recent haemorrhage, that is why CT is used to examine patients with head, chest, abdominal and pelvic cavities injuries, as well as strikes at early stage. Using contrast substance ensures getting qualitative images of vessels, kidneys and testiness with CT. CT is also a method of choise in detecting and staging of different oncologic lesions. Using MRI one can see images of soft tissues (cartilages, ligaments, brain, etc.). Hence MRI is used for example in assumptions of ligaments ruptures and to avoid diskal hernias. MRI is widely used in neurosurgery and neurology (old brain traumas, strokes at later stage, assumptions of brain and spinal cord tumors).
There are many indications for MRI application. For example MRI of the brain can be started only when there are first signs of intracranial hypertension, frequent intensifying headache, assumptions of meningitis, cerebellar disorders, neurological focal signs (diplopia, visual acuity failure) accompanied by headache. Leg stiffness while walking, pelfic organs disfunction, pain in the loin or thoracic spine of unknown origin being the indications for MRI tests of the spinal cord. MRI can be started after thorough neurologic examination by neurologist in order to specify diagnosis and find out if the patient has certain symptoms difficult for explanation.
For magnetic resonance imaging (MRI) a patient is placed in a specially created magnetic field. Changing resonance part location enables scanning of the whole organism. Artificial metal objects that can magnetize, including heart pacemaker, can distort image during MRI and affect changes objective evaluation in pathological processes, and sometimes they can cause cardiac malfunction. In such cases MRI test should be substituted with computer tomographic scanning, during which sectional roentgenography is used for a certain part of the human body.
Metal objects in the organism. Heart pacemaker. Plaster bandage with metal construction. Permanent make-up in the examination area. First three months of pregnancy. Inner ear implant. Cell augmentors or neuronic stimulators.
When the patient has absolute or relative contradictions to magnetic resonance imaging.
Usually examination of one anatomic area of the human organism using magnetic resonance imaging scanner takes from 15 up to 45 minutes.
- for acute and chronic pathological processes in liver, biliary system, pancreas, spleen.
- for assumptions of benign or malignant, primary or secondary liver or biliary system, pancreas, spleen formations.
- for liver or biliary system, pancreas, spleen traumatic injuries.
- for visualization of congenital malformations of different abdominal organs.
- for obstructive jaundice clinical findings.
- for hepatomegaly, splenomegaly, pancreas parts enlargement of unkown origin.
- for oncologic imaging.
- for detection and evaluation of lymph nodes condition.
- for assumptions of pathological changes of aorta and other abdominal cavity vessels.
- for evaluation of the abdominal cavity organs treatment dynamic.
MR examination can result in certain increase of temperature of the body, that is whythis examination is not recommended during first three months of pregnancy. Starting from third till nonth months of pregnancy MRI is safe for pregnant women, though if there’s a chance to postpone it till after giving birth, it is better to be this way.