الفهرس 
INTRODUCTION & AIM OFTHEWORKOnly 14 pages are availabe for public view
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Abstract
The present work was aiming to study the application of MR! ·in gastrointestinal surgery and to give an insight about its physical principles, advantages and hazards.
After review of literatures we noted that:
Only those atomic nuclei with odd numbers of protons or neutrons have the potential to be imaged. charge and spin cause the hydrogen proton to behave as a magnetic dipole which is oriented randomly and have a zero net magnetization. The introduction of an external magnetic field forces this magnetic dipoles to precess about its axes and align in one or two directions creating an excess in the net magnetization. This excess generates the signals that obtained by the receiving coils and measured in MRI experiment.
The greater the strength and duration of energy derived hom RF pulse, the greater the flip mgh which is user selectable and determined by the particular imaging sequence.
The MR image quality depends on: The pulse sequence (SE, GE, IR, .. ), Image p< rameters (Proton density, TI,T2, tlow efTect, .. ) and the examined tissue ( anatomy, physiology, biochemistry and p:1thology) induding the contrast <Jgent.
The application of MRI in gastrointestinal surgery ineiL1des its usc as a method of investigation iind the use of intraoperative MR to guide the surgical procedures.