Prophylaxis of migraine with oral magnesium: results from a prospective, multi-center, placebo-controlled and double-blind randomized study.

In order to evaluate the prophylactic effect of oral magnesium, 81 patients aged 18-65 years with migraine according to the International Headache Society (IHS) criteria (mean attack frequency 3.6 per month) were examined. After a prospective baseline period of 4 weeks they received oral 600 mg (24 mmol) magnesium (trimagnesium dicitrate) daily for 12 weeks or placebo. In weeks 9-12 the attack frequency was reduced by 41.6% in the magnesium group and by 15.8% in the placebo group compared to the baseline (p < 0.05). The number of days with migraine and the drug consumption for symptomatic treatment per patient also decreased significantly in the magnesium group. Duration and intensity of the attacks and the drug consumption per attack also tended to decrease compared to placebo but failed to be significant. Adverse events were diarrhea (18.6%) and gastric irritation (4.7%). High-dose oral magnesium appears to be effective in migraine prophylaxis.

Increase in magnesium plasma level after orally administered trimagnesium dicitrate.

Magnesium plasma concentrations were measured in healthy probands before and after administration of trimagnesium dicitrate by the oral and intravenous routes. There was a notable circadian fluctuation of the plasma concentration with a peak in the evening hours. After oral administration of 12 and 24 mmol magnesium, a long-lasting, statistically significant increase in plasma magnesium concentration measured as the increase in area under the curve (AUC) between 0 and 12 h, of 3.1% and 4.6%, respectively, was found. After intravenous administration of 4 and 8 mmol magnesium, AUCs increased by 9.5% and 16.1%, respectively. The decline in the plasma magnesium concentration after i.v. administration was compatible with a three-compartment model with a terminal half-time of about 8 h. Although no absolute value of the oral bioavailability of trimagnesium dicitrate could be determined from the data, our results may be important in helping to elucidate the influence of magnesium preparations on the plasma magnesium concentration. By comparing the effects of different preparations, it should be possible to estimate the relative oral bioavailability and the bioequivalence of these preparations.

Comparative effects of a Mg-enriched diet and different orally administered magnesium oxide preparations on ionized Mg, Mg metabolism and electrolytes in serum of human volunteers.

OBJECTIVE: To determine whether: 1) short-term dietary elevation in magnesium (Mg) intake could alter serum ionized Mg (IMg2+), total Mg (TMg); % ionized Mg (% IMg2+) and other cations; and 2) different formulated preparations of Mg oxide (MgO) in the presence and absence of phosphate could alter serum IMg2+, TMg, % IMg2+ and other cations in Mg-loaded subjects. METHODS: A randomized, triple cross-over study was performed on a rigorously defined group of normal male volunteers. Eighteen males were administered diets containing four to five times the United States recommended daily allowance (USRDA) of Mg followed by a randomization of three different MgO preparations, in the presence or absence of phosphate, containing equimolar amounts (12.34 mmol) of elemental Mg. Forty age-matched volunteers served as reference range controls. Specific ion selective electrodes were utilized to measure IMg2+, ionized calcium (ICa2+), sodium (Na+) potassium (K+) and hydrogen ion concentration (H+). Measurement of urinary excretion of Mg as well as TMg were determined by atomic absorption spectroscopy. RESULTS: Diets enriched with different oral formulations of Mg given for 6 days result in significant elevations in serum IMg2+ and % IMg2+ but not TMg, ICa2+, K+ or H+ in normal subjects. Although such Mg-loaded subjects demonstrate significant elevation in urinary excretion of Mg, no further changes in IMg2+, TMg or any of the serum cations were produced by ingestion of either of the three MgO preparations. Subjects showing normally low basal levels of serum IMg2+, (< or = 0.54 mM/L), could easily have their serum IMg2+ level manipulated by diets enriched with Mg, whereas subjects having average normal or high normal IMg2+ levels did not have their IMg2+ elevated significantly with either diets enriched with Mg or with exogenous MgO. CONCLUSION: These results indicate that since serum IMg2+ and % IMg2+, but not TMg, can be altered by dietary intake, previous or future findings which may indicate no change in TMg by diet may not reflect changes in biologically-active Mg.

Three-dimensional magnetic resonance imaging in skull base lesions.

Three-dimensional (3D) magnetic resonance (MR) imaging is a new digital technique developed 2 years ago by a multidisciplinary group of head and neck surgeons, clinical radiologists, and mathematicians at the University of Munich. In this study, the clinical value of this method, which has been improved significantly during the last 9 months, is evaluated in lesions of the skull base. Our results indicate that 3D reconstruction based on two-dimensional (2D) MR images reveals topographic details of interesting structures. In addition, this method offers new possibilities for the preoperative planning of tumor resection, particularly in lesions close to the skull base. However, this imaging technique will have to be improved before it achieves widespread clinical use.

[Nuclear magnetic resonance tomography of children's thorax]. / Kernspintomographie des kindlichen Thorax.

Magnetic Resonance Imaging of the pediatric chest was performed in 53 patients. All examinations were performed using a 1.0 and 1.5 Tesla superconducting MR imager. 80% of the children were examined using anesthesia with a ventilation of 20% inspiration and 80% expiration. After performing the MR examination in 55% of the cases an operation was performed. In 29 patients anomalies of the brachiocephalic trunc were found. In four patients MR detected a doubled aortic arch, in four patients we found a dilated arch. In eight children a dilated pulmonary artery was diagnosed. In combination with eight tracheobronchoscopy, MR imaging proved to be the diagnostic method of choice for the evaluation of anomalies of the mediastinum. New developments like fast imaging techniques and 3D acquisition promise a further diagnostic improvement in the mediastinum.

Magnetic resonance imaging as a new diagnostic criterion in paediatric airway obstruction.

Magnetic resonance imaging of the trachea was performed in 21 children with congenital or acquired narrowing of the trachea or main bronchi. Diagnosis included aortic arch anomalies, innominate artery compression, pulmonary artery compression and tracheomalacia. All patients were examined after bronchoscopy. The demonstration of the trachea and the surrounding tissue and vessels on MR images enables the cause of tracheal compression and the degree and location of collapse to be evaluated. MRI is a modality well suited to characterizing tracheal narrowing without employing ionizing radiation or intravenous contrast medium. All MRI examinations were carried out with the patient under general anaesthesia so as not to risk pulmonary deterioration during sedation. In the cases presented MRI is the diagnostic step of choice after tracheobronchoscopy and broadens the diagnostic potential in extrinsic tracheal or bronchial stenosis in paediatric patients.

MRI in tracheal stenosis by innominate artery in children.

Pediatric airway obstruction due to anomalies of the course of the innominate artery may produce respiratory distress. MR imaging of the trachea was performed after bronchoscopy on forty-one children with congenital tracheal stenosis. Bronchoscopy only allows the evaluation of the lumen of the trachea, and the degree and location of collapse, and it may be difficult to determine the etiology of the tracheal narrowing. In eighteen out of the forty-one patients MR imaging showed a compression of the trachea by the innominate artery. The MR imaging diagnoses were subsequently compared for accuracy with the diagnoses determined by direct surgical observations. MR imaging of the trachea, the surrounding tissue and vessels allows the evaluation of the cause of tracheal compression and the degree and location of collapse. For evaluation of the cause of airway obstruction. MRI is an ideal method depicting detailed anatomic structure without employing ionizing radiation or intravenous contrast medium.

Parotid gland: plain and gadolinium-enhanced MR imaging.

The purpose of this study was to show the typical appearance of lesions of the parotid gland with plain MR imaging and MR imaging enhanced with gadopentetate dimeglumine. Seventeen patients with inflammatory changes and 43 with benign and malignant tumors were studied. The examinations were carried out with plain T1-weighted sequences with a repetition time (TR) of 500 msec and an echo time (TE) of 25 msec (TR/TE = 500/25), T2-weighted sequences (1,600/90), and gadolinium-enhanced T1-weighted sequences in axial, coronal, and sagittal orientations. For identifying normal anatomic structures such as the facial nerve and the main duct, the administration of gadopentetate dimeglumine was helpful. In inflammatory changes, gadolinium-enhanced images showed no diagnostic advantages. Gadopentetate dimeglumine proved helpful in delineating tumorous lesions and in differentiating benign and malignant lesions. However, an exact differentiation of the different histologic types was not possible. Post-operative fibrosis could be differentiated from recurrent tumors after administration of gadolinium. If a question regarding infiltration or definition of the boundaries of a lesion cannot be answered with non-enhanced MR imaging, gadopentetate dimeglumine administration is advised. However, for routine imaging of the parotid gland, its use is not recommended.

[The further development of the 3D-MRI reconstruction technic for the head-neck area]. / Weiterentwicklung der 3D-KST-Rekonstruktionstechnik im Kopf-Hals-Bereich.

Twenty-one healthy volunteers and seventeen patients with head and neck lesions were examined with 3D MR imaging since the end of 1988. A new kind of reconstruction mode was used, which shows the structures of the region of interest by overlaying a predetermined window within the three-dimensional reconstruction of the head. Using this mode, the morphology of the lesion could be evaluated more precisely than by using individual two-dimensional slices. With regard to preoperative surgery planning, the previous results were insufficient. With the new development and increased capacity of the MRI-technique and improvement of the reconstruction mode it is now possible to "cut" several slices in different orientations into the head achieving higher resolution of the images. The innovation of the method and its actual clinical value is discussed in the example of a meningioma of the sphenoid which has been examined by both reconstruction modes.

[A new method of 3-dimensional reconstruction of the head and neck]. / Eine neue Methode zur 3D-Rekonstruktion im Kopf-Hals-Bereich.

In the past decades the development of MRI has significantly increased the importance of diagnostic imaging of head and neck lesions. The standard imaging method is based on two-dimensional slices. The present study was performed to evaluate the diagnostic value of 3D MRI-reconstructions for head and neck lesions. The 3D reconstruction method and the results of the 3D-reconstructed images are presented. Important aspects of the interesting structures can be evaluated much more easily with reconstructed images than by mentally reconstructing two-dimensional slices. In the light of the present results, 3D reconstruction promises to be an accurate method for the diagnosis of head and neck lesions and might be of clinical importance in the future.

[3D-MRT-reconstructions of space-occupying lesions in the head and neck regions]. / 3D-KST-Rekonstruktionen bei Raumforderungen im Kopf-Hals-Bereich.

3-D reconstructions in the head and neck were carried out on 21 normals and 11 patients with space-occupying lesions, both before and after the administration of Gd-DTPA. The 3-D reconstructions were obtained by the "ray-tracing" method. For the 3-D reconstructions, portions of the skull surface image were removed to permit views of the deeper tissues. The 3-D reconstructions included an hypoglossus neurinoma, a glomus tumour, two carcinomas of the maxillary antra, three naso-pharyngeal carcinomas, a parotid adenoma, an oro-pharyngeal haemangioma and two lesions in the neck. The 3-D reconstructions provided a better understanding of the morphology than was obtained from the two-dimensional images. 3-D reconstructions of lesions in the head and neck will become a valuable diagnostic method for demonstrating space-occupying lesions, particularly with regard to surgical planning.

MR imaging in pediatric airway obstruction.

Magnetic resonance (MR) imaging of the trachea was performed in 27 children with congenital tracheal narrowing. The diagnoses included aortic arch anomalies (n = 7), innominate artery compression (n = 13), pulmonary artery compression (n = 5), and tracheomalacia (n = 2). Demonstration of the trachea and the surrounding tissue and vessels on MR images allowed the evaluation of the cause of tracheal compression and the degree and location of collapse. Patients were examined with MR imaging if the cause of airway obstruction was still unclear after bronchoscopy. It is concluded that MR imaging is a well suited modality for characterizing tracheal narrowing without using ionizing radiation or intravenous contrast medium.

[Magnetic resonance tomography as a new diagnostic criterium in vascular-induced stenoses of the upper airways in childhood]. / Die Kernspintomographie (KST) als neues diagnostisches Kriterium bei gefässbedingten Stenosen der oberen Luftwege im Kindesalter.

Magnetic resonance (MR) imaging of the trachea was performed in twenty-one children with congenital or acquired narrowing of the trachea or main bronchi. The demonstration of the trachea and the surrounding tissue and vessels on MR images permitted the evaluation of the cause of trachea, compression and the degree and location of collapse. MRI is a well-suited modality for characterizing tracheal narrowing without employing ionizing irradiation or intravenous contrast medium. In the cases presented MRI should be the diagnostic step of choice after tracheo-bronchoscopy. It is an enrichment of the diagnostic possibilities for extrinsic tracheal or bronchial stenosis in pediatric patients.

[The value of MRT of the thorax in congenital tracheal stenoses]. / Wertigkeit der KST des Thorax bei kongenitalen Trachealstenosen.

MRI of the thorax was performed in 24 children aged between six weeks and five years, in whom a tracheal stenosis had been demonstrated by bronchoscopy. Since bronchoscopy can only demonstrate the interior of the trachea, various imaging methods, such as CT and angiography, were used to demonstrate the topography and cause of the tracheal stenosis. MRI has shown that the most common cause of a stenosis in the central section of the trachea is focal compression by an aberrant brachiocephalic trunk (10 cases). Stenosis of the distal trachea could be due to anomalies of the aortic arch (5 cases), a dilated pulmonary artery (4 cases) or a soft tissue mass (3 cases). In all these patients, MRI was greatly superior to the conventional methods. By using a special technique, MRI made it possible to clarify the cause and localisation of a tracheal stenosis by a non-invasive examination.