[BASICS OF MRI MAGNETIC RESONANCE IMAGING]
SEPTEMBER 18, 2004
Lege Artis Medicinae - 2004;14(08-09)
SEPTEMBER 18, 2004
Lege Artis Medicinae - 2004;14(08-09)
[Magnetic resonance imaging (MRI) is a young, developing technology used to create images with extraordinary detail of body tissue or the brain by applying nuclear magnetic resonance phenomena. The MRI technique uses a pulse of radio-frequency energy to excite the hydrogen nuclei, the protons. The distribution of hydrogen nuclei of water and fat in the body depends on the tissue type and whether or not the tissue is healthy or diseased. The image brightness is a complex function of properties in the region of interest, which include parameters of protons density and the relaxation times of the protons. Manipulating these properties is accomplished by varying the experiment (pulse sequence) used at the time of examination to yield images that contains different contrast. Although MRI is normally a noninvasive technique, contrast agents can be administered to a subject to enhance a region of interest. There are now more than 22,000 MR systems in use worldwide. MR is one of the best diagnostic exams for imaging many types of soft-tissue including: the brain, the spine, the heart, aorta and coronary arteries, the organs of the upper abdomen and the pelvis as well as the joints.]
Lege Artis Medicinae
[Target blood pressure and reduction in cardiovascular morbidity and mortality have to be accomplished always with the consideration of target organ lesion. Fixed-combination antihypertensive therapy has become accepted based on the recommendations of international and Hungarian medical associations that are aware of the results of evidence based medicine. The fix combinational treatment is more favorable for patients’ compliance. The daily dosage of drugs with 24 hour effect improves the patients’ cooperativeness. During fix combinational treatment higher efficiency, smaller dose and fewer side effects were observed. In combination, the effects of the drugs on blood pressure are additive without any increase in adverse effects. Last, but not least the cost of drugs of fixed combination are lower than buying the drugs separately. After careful consideration the fixed combination therapy can be recommended to the everyday practice.]
Lege Artis Medicinae
[The Hungarian Case-Control Surveillance System of Congenital Abnormalities can provide appropriate data for the evaluation of risk and benefits of drugs and pregnancy supplements in pregnant women. Among the main principles, the importance of time factor (the first trimester concept is outdated) and the explanation of frequent false teratogenic findings (e.g. recall bias, chance effect, etc.) are discussed. The main conclusion is that at present the exaggerated teratogenic risk of drugs is much more harmful for the fetus than the rare teratogenic effect of some drugs themselves. Medical doctors and other experts therefore need more education to know the principles and findings of modern human teratology because it may help us to have a better balance between the risks and benefits of drug use during pregnancy. On the other hand, the primary prevention of neural-tube defects and some other congenital abnormalities is demonstrated by periconceptional folic acid or folic acid-containing multivitamin supplementation. Unfortunately, this new method is used rarely and inappropriately (due to the late onset of supplementation) in Hungary.]
[Certain viral infections, gene mutations and immune suppression are likely to play some role in the development of malignant lymphomas. The clinical stage at the time of diagnosis is a decisive factor of prognosis. The evaluation of the nodal and extranodal manifestation of the disease is performed by standardized imaging techniques. Most frequent extranodal manifestation involves the bone marrow, the lung and the gastrointestinal tract. Different imaging techniques are indispensable in monitoring the effectiveness of the treatment and in long term follow up.]
Background and aims – Description of two cases of rare intravascular large B-cell lymphoma and secondary T-cell lymphoma diagnosed postmortem, that manifested clinically as longitudinally extensive transverse myelitis (LETM). We discuss causes of diagnostic difficulties, deceptive radiological and histological investigations, and outline diagnostic procedures based on our and previously reported cases. Case reports – Our first case, a 48-year-old female was admitted to the neurological department due to paraparesis. MRI suggested LETM, but the treatments were ineffective. She died after four weeks because of pneumonia and untreatable polyserositis. Pathological examination revealed intravascular large B-cell lymphoma (IVL). Our second case, a 61-year-old man presented with headache and paraparesis. MRI showed small bitemporal lesions and lesions suggesting LETM. Diagnostic investigations were unsuccessful, including tests for possible lymphoma (CSF flow cytometry and muscle biopsy for suspected IVL). Chest CT showed focal inflammation in a small area of the lung, and adrenal adenoma. Brain biopsy sample from the affected temporal area suggested T-cell mediated lymphocytic (paraneoplastic or viral) meningoencephalitis and excluded diffuse large B-cell lymphoma. The symptoms worsened, and the patient died in the sixth week of disease. The pathological examination of the presumed adenoma in the adrenal gland, the pancreatic tail and the lung lesions revealed peripheral T-cell lymphoma, as did the brain and spinal cord lesions. Even at histological examination, the T-cell lymphoma had the misleading appearance of inflammatory condition as did the MRI. Conclusion – Lymphoma can manifest as LETM. In cases of etiologically unclear atypical LETM in patients older than 40 years, a random skin biopsy (with subcutaneous adipose tissue) from the thigh and from the abdomen is strongly recommended as soon as possible. This may detect IVL and provide the possibility of prompt chemotherapy. In case of suspicion of lymphoma, parallel examination of the CSF by flow cytometry is also recommended. If skin biopsy is negative but lymphoma suspicion remains high, biopsy from other sites (bone marrow, lymph nodes or adrenal gland lesion) or from a simultaneously existing cerebral lesion is suggested, to exclude or prove diffuse large B-cell lymphoma, IVL, or a rare T-cell lymphoma.
Intracranial localization of Ewing’s sarcoma is considerably very rare. Herein, we present clinical and neuroimaging findings regarding a 4-year-old boy with intracranial Ewing’s sarcoma. He was born prematurely, suffered intraventricular haemorrhage, posthaemorrhagic hydrocephalus developed, and a ventriculoperitoneal shunt was inserted in the newborn period. The patient endured regular follow ups, no signs of shunt malfunction nor increased intracranial pressure were observed. The last neuroimaging examination was performed at 8 months of age. Upon reaching the age of 4 years, repeated vomiting and focal seizures began, and symptoms of increased intracranial pressure were detected. A brain MRI depicted a left frontoparietal space-occupying lesion infiltrating the superior sagittal sinus. The patient underwent a craniotomy resulting in the total excision of the tumour. The histological examination of the tissue revealed a small round blue cell tumour. The diagnosis was confirmed by the detection of EWSR1 gene translocation with FISH (fluorescent in situ hybridization). No additional metastases were detected during the staging examinations. The patient was treated in accordance to the EuroEwing 99 protocol. Today, ten years onward, the patient is tumour and seizure free and has a reasonably high quality of life.
Evidence suggests that pathogen-associated pattern recognition receptors (Toll-like receptors, TLRs) are implicated in the pathophysiology of schizophrenia. TLRs are important in both peripheral immune responses and neuronal plasticity. However, the relationship between peripheral TLR expression and regional brain volumes is unknown in schizophrenia. We therefore assessed 30 drug-naïve, first-episode patients with schizophrenia. TLR4+/TLR1+ monocytes were measured using flow-cytometry. High resolution magnetic resonance images (T1 MRI) were obtained and analyzed with FreeSurfer. Results revealed significant negative correlations between the percentage of TLR4+ monocytes, mean fluorescent intensities, and brain volumes in frontal and anterior cingulate regions. The measures of TLR1+ monocytes did not show significant relationships with regional brain volumes. These results raise the possibility that abnormal TLR-activation is associated with decreased brain volumes in schizophrenia.
Clinical NeuroscienceLate carcinomatous meningitis as vertigo
Clinical NeuroscienceAlexithymia is associated with cognitive impairment in patients with Parkinson’s disease
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