Heinrich Kolem

Duration of lithium treatment and brain lithium concentration in patients with unipolar and schizoaffective disorder : A study with magnetic resonance spectroscopy

Twenty psychiatric patients on lithium medication were examined with 7-Li-magnetic resonance spectroscopy of the brain. Patients on long-term lithium treatment (> 6 months) were compared with a short-term group who had been taking lithium for between 4 and 8 weeks. Patients met DSM-III-R criteria for either recurrent unipolar depressive disorder (DSM-III-R 296.3x) or schizoaffective disorder, depressive type (DSM-III-R 295.70). The brain:serum lithium ratio was 0.76 +/- 0.26; there was no significant difference between short-term and long-term treatment. In the group of long-term treatment patients there was a positive correlation between lithium dose per day and brain lithium concentration (R = .72, p < .01), and between lithium plasma concentration and brain lithium concentration (R = .65, p < .05). In the short-term group, however, there was no significant correlation for these parameters. No differences between unipolar and schizoaffective disorder were found.

Nuclear magnetic resonance apparatus having at least two transmission frequencies

For improving the spectral resolution and/or the signal-to-noise ratio of a nuclear magnetic resonance apparatus for examining first types of atomic nuclei that are nuclear-magnetically coupled to second types of atomic nuclei, signals are additionally emitted on the resonant frequency of the second type of atomic nucleus during the examination of the first type of atomic nucleus. To this end, the nuclear magnetic resonance apparatus includes a reception channel and only one transmission channel for both resonant frequencies. The transmission channel contains a respective synthesizer for each resonant frequency, which define the transmission frequency and contains a modulator unit shared in common by both resonant frequencies.

5530352 Nuclear magnetic resonance tomography apparatus having dynamically localized shimming of the basic magnetic field

In multi-slice methods, wherein at least one further slice is excited within the repetition time for a pulse sequence for the excitation and read-out of a slice the shimming ensues dynamically dependent on the respectively measured slice. The homogeneity in the excited slice can thus be improved compared to a global shimming.

Basics of Magnetic Resonance Imaging and Magnetic Resonance Spectroscopy

In this chapter, the basic principles of magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) (Sects. 2.2, 2.3, and 2.4), the technical components of the MRI scanner (Sect. 2.5), and the basics of contrast agents and the application thereof (Sect. 2.6) are described. Furthermore, flow phenomena and MR angiography (Sect. 2.7) as well as diffusion and tensor imaging (Sect. 2.7) are elucidated.

Chemical shift imaging

The basic task of making separate images of the two largest peaks of the MR proton spectrum (water and fat) has been approached as a problem of pixel by pixel spectroscopy and as a phase correction problem wherein one encodes information about frequency into the phase angle of a complex MR image. Images of induced magnRtic field (susceptibility) can also be made as part of the fat/water image calculations.

Metabolische Bildgebung am Gehirn des Menschen mittels lokalisierter in vivo 31P-1H-Doppelresonanz-Spektroskopie

Zusammenfassung Eine elegante Methode fur die lokalisierte in vivo 31 P-MR-Spektroskopie am Gehirn des Menschen ist das Chemical-Shift-Imaging. Eine signifikante Verbesserung des Signal-Rausch-Verhaltnisses bei gleichbleibender Meszeit wurde von uns mit der Doppelresonanztechnik erzielt. Durch zusatzliche Hochfrequenz-Einstrahlung auf der Protonenfrequenz wird ein Kern-Overhauser-Effekt im dipolar gekoppelten 31P-1 H-Spinsystem induziert. In Probandenmessungen wurde ein Signalgewinn von bis zu 42 % beobachtet. Das 31P-Chemical-Shift-Imaging wird in einer klinischen Studie zur Kontrolle der prachirurgischen Embolisation von Meningeomen eingesetzt.