brash , brazen , daredevil , foolhardy , heedless , hotheaded , impetuous , imprudent , impulsive , incautious , madcap , overbold , overconfident , rash , reckless , thoughtless , wild ;
Its proof of concept of blood-oxygen-level dependent contrast imaging was provided by Seiji Ogawa and colleagues in 1990, following an experiment which demonstrated that an in vivo change of blood oxygenation could be detected with MRI.  In Ogawa's experiments,blood-oxygen-level dependent imaging of rodent brain slice contrast in different components of the air. At high magnetic fields, water proton magnetic resonance images of brains of live mice and rats under anesthetization have been measured by a gradient echo pulse sequence. Experiments shown that when the content of oxygen in the breathing gas changed gradually, the contrast of these images changed gradually. Ogawa proposed and proved that the oxyhemoglobin and deoxyhemoglobin is the major contribution of this difference.