MRI Magnetic Resonance Imaging

Posted by Fatimah Imah Kamis, 19 Mei 2011 0 comments
MRI (Magnetic Resonance Imaging) MRI plays an important role in the diagnosis of a stroke because:
1. MRI can sometimes show the existence of cerebral ischemia at an early stage, before it can be seen on CT-scan and often when the CT-scan remained negative.
2. MRI can often show the existence of infarction in the brain stem, cerebellum, or temporal lobes are not visible on CT-scan.
3. The ability of MRI in the search for deep-vein thrombosis as a cause of infarction is better than CT-scan.

4. MRI is more sensitive in finding small infarction (lakuner). CT-scan is still better dihanding MRI in the acute phase of stroke when the main goal to find the bleeding and there is a problem in terms of cooperation with the patient.
5. Penyengatan contrast in MRI is useful in determining the possibility of an infarct age and look for a tumor or AVM as a cause of stroke.

Note: SPECT (single photon emission computed tomography) can localize ischemia within a few hours after a stroke.

Arteriography, both worked with conventional and digital techniques, is intended to (a) identifying a lesion that can be corrected with surgery such as intracranial aneurysms and AVM, carotid artery stenosis, and carotid artery plaque is ulcerated, (b) help confirm the diagnosis, and (c) confirm the diagnosis before giving antikoagulansia done. In planning an arteriography, is clinically important to determine which systems are involved in stroke, carotid system or the system vertebrobasiler. Where possible, angiography is done with catheterization technique by an experienced radiologist.

Electroencephalography (EEG)
Electroencephalography (EEG) can help determine the localization of cortical dysfunction, and occasionally in the thalamus lesions. EEG can be abnormal in the first hours after a stroke, although the CT-scan was normal. EEG will usually be normal in the area of stroke in the posterior circulation or lacunar stroke and abnormal in the anterior circulation stroke or embolism region.
EEG is usually abnormal in stroke large blood vessels or embolism.

EEG is an important thing to do when a suspected epileptic activity. Weakness after a stroke may be a part of the post-attack epilesi (Todd paralysis).

Lumbar puncture
When the cerebrospinal fluid (CSF) containing blood (erythrocytes) 1000) and the pressure increased (200 mmH2O), lumbar puncture support the existence of a hemorrhage. Please note that normal CSF pressure and is not found in CSF cells can occur in 10% of intracerebral hemorrhage. All subarachnoid hemorrhage showed significant bleeding in CSS, usually containing erythrocytes 25,000.
Lumbar puncture with the content of erythrocytes 50-500 in the CSS to direct suspicion on cerebral embolism, and appeared to CSS clear in most of embolism.

In cerebral thrombosis and lacunar stroke was not found in CSS cells. Sometimes it seems the leucocytes in the CSF after the attacks of thrombosis or bleeding. Erythrocytes in large numbers (10000-20000) is sometimes seen in myocardial blood after an attack of cerebral embolism. After further development in the presence of CT, lumbar puncture is rarely done anymore in order to evaluate stroke patients lumbar puncture is done when:
• Suspicion of central nervous system infection.
• The possibility of enforcement of the diagnosis of sub-arachnoid haemorrhage. CT scans can produce false negative in 50-10% of patients with subarachnoid hemorrhage,
• The possibility of enforcement of the diagnosis of intra-cerebral hemorrhage, but did not allow performed CT-scan, and found no signs of increased intracranial pressure.
• Before you start 'giving antikoagulansia, in order to rule out any bleeding if it is not possible to do CT scan.
• suspicion of arteritis.
• Diagnosis of patients is unclear.

How MRI clinical applications?
MRI examination aims to identify the characteristics morpologik (location, size, shape, expansion and others of pathological conditions. These objectives can be obtained by assessing any one or combination of cross-sectional images of the body akial, sagittal, coronal or oblique depending on the location of organs and the possibility of pathology. The type of MRI examination in accordance with the organ that will be seen, for example: 1. Check to see abnormalities in the head: the pituitary gland, inner ear holes, eye socket, sinus, 2. Examination of the brain to detect: stroke / infarction, picture of brain function, bleeding, infection, tumor, congenital abnormalities, vascular abnormalities such as aneurysm, angioma, the process of degeneration, atrophy; 3. Examination of the spine to see the process of degeneration (HNP), tumor, infection, trauma, congenital abnormalities. 4. Musculo-skeletal examination for organ : knee, shoulder, elbow, wrist, ankle, foot, to detect tear cartilage, tendons, ligaments, tumors, infection / abscess, and others; 5. Examination Abdomen to see the heart, kidneys, bags and bile duct, pakreas , spleen, gynecological organs, prostate, bladder 6. Inspection Thorax to view: the lungs, heart.

Source: fkunhas


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