Research Erik Raman

Abstract

This project deals with the processing of simulteneously acquired EEG and fMRI data as to obtain an accurate localization of epileptic brain activity. The research will focuss on the reduction of MR related artefacts in EEG data and vice versa, on image processing of magnitude MR data and on the modification of the MR imaging sequence after EEG data processing.

Researcher(s)

• Promoter: Van Dyck Dirk
• Co-promoter: Raman Erik
• Fellow: Sijbers Jan

Research team(s)

Project type(s)

• Research Project

Abstract

It is the major function of cutaneous blood flow to control the loss of heat from the body surface. In the rat, almost 20% of the total body heat-loss occurs by sympathetically mediated increases in blood flow through a system of arteriovenous anastomoses (AVAs) in the skin of the tail which are absent at the base and abundant at the tip. The mechanisms which are really involved in thermoregulation of the rat remained unsolved since none of the work cited, approaches both temperature and blood vessel size. Our aim was to monitor online the blood vessel temperature, as measured externally, and the arterial and venous vessel size and their mutual vascular volume interactions using in vivo MRA. Application: multi slice gradient echo sequence with TE/TR 6/20ms, FOV 20mm. The experiment protocol was repeated at 3 important regions of the tail: base, middle and tip during a gradual rise of rectal temperature from 36°C to 40°C. We measured also tail blood temperature applying temperature dependent resistors attached with adhesive tape and carefully positioned at the ventral artery (Ta) and lateral vein (Tv). In all cases, MRA data sets yielded a perfect representation of the tail's vascular anatomy (its 3 major axial artery-vein pairs, one ventral and two lateral). The diameter of the ventral artery and the lateral veins of the heat-loaded animal increased clearly. The size of the 3 smaller veins of the ventral artery-vein pair increased only beyond a rectal temperature of 39°C. Calculation of (Ta-Tv) in function of the rectal temperature during heating, learnt more about the thermogenetic vaso-activity effect of the tail blood vessels and the onset of vasodilation. At the tail base, a maximum difference was observed at rectal temperature of 38°C and a minimum at 39°C. At the middle and the tip of the tail, we observed a steady rise of (Ta-Tv). If we assume that vasodilatation is a synchronical process along the length of the tail, then the difference in (Ta-Tv) is due to the presence of AVAs.

Researcher(s)

• Promoter: Raman Erik
• Co-promoter: Van Der Linden Annemie

Research team(s)

Project type(s)

• Research Project

Abstract

The purpose of this project is the improvement of spatial resolution in the field of Magnetic Resonance Imaging. The system PSF will be determined theoretically and experimentally. This knowledge will be used in the optimalisation of a Fourier reconstruction scheme.

Researcher(s)

• Promoter: Raman Erik
• Co-promoter: Sijbers Jan
• Co-promoter: Van Dyck Dirk

Research team(s)

Project type(s)

• Research Project

Abstract

With NMR 'flow imaging' techniques it is possible to measure flow speed of laminary flows. One can also measure the complete course of speed of pulsed flow (mechanical hydraulic model of arterial blood flow) provided that an adapted triggering is applied. A recently self-built gradient set will allow to obtain a higher image resolution.

Researcher(s)

• Promoter: Raman Erik
• Co-promoter: Van Camp Karel
• Co-promoter: Van Der Linden Annemie

Research team(s)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Van Dyck Dirk
• Co-promoter: Dommisse Roger
• Co-promoter: Jacob Willem
• Co-promoter: Lowen Bob
• Co-promoter: Raman Erik
• Co-promoter: Rousseeuw Peter
• Co-promoter: Van Espen Piet
• Co-promoter: Van Landuyt Joseph
• Co-promoter: Verschoren Alain

Research team(s)

Project type(s)

• Research Project