04-02-2016, 02:42 PM
Introduction
1. Magnetic Resonance Imagining (MRI) Magnetic fields
In an externally applied magnetic field, atomic nuclei with an odd number of nucleons (protons + neutrons) process Spin axis wobbles Rate determined both by properties of the atom And by the strength of the magnetic field Hydrogen atoms in a 1.5 Tesla field process at ~64 MHz Radio frequency [RF] range. Cerebral blood flow or perfusion is a measure of the rate of delivery of arterial blood to a capillary Bed in tissue.The standard unit of measurement for CBF is (milliliters of blood)/(100 grams of tissue minute), and a typical value in the human brain is 60 ml/(100 g)/minute.Imaging sequences based upon blood oxygenation level dependent (BOLD) contrast are currently the predominant method for functional magnetic resonance imaging (fMRI) of the brain.BOLD signal reflects the total amount of deoxyhemoglobin (dHBO2)