UTILIZATION OF 180-DEGREE PULSES IN HIGH-SPEED MRI

THIS RESEARCH WILL CONTRIBUTE TO THE DEVELOPMENT OF A WHOLE-BODY MAGNETIC RESONANCE IMAGING (MRI) SYSTEM CAPABLE OF ACQUIRING COMPLETE TOMOGRAPHIC PROTON IMAGES IN ABOUT 50 MILLISECONDS. IN PARTICULAR, THE POTENTIAL UTILIZATION OF 180-DEGREE RADIOFREQUENCY PULSES IS ADDRESSED AS A MEANS OF ELIMINATING ARTIFACTS THAT ARISE AS A RESULT OF MAGNETIC FIELD STRENGTHS MANDATED BY SIGNAL-TO-NOISE RATIO AND SPATIAL RESOLUTION REQUIREMENTS. ALTHOUGH NOW ACCEPTED AS AN EXTREMELY VALUABLE DIAGNOSTIC TECHNIQUE, MRI IS LIMITED IN ITS APPLICABILITY TO ORGANS THAT MOVE INVOLUNTARILY, ESPECIALLY THE HEART. THIS IS A DIRECT CONSEQUENCE OF THE LONG SCAN TIMES (TYPICALLY SEVERAL MINUTES) CURRENTLY REQUIRED. IN ADDITION TO ELIMINATING THE MOTION ARTIFACTS THEREBY OCCASIONED, THE PROPOSED HIGH-SPEED TECHNIQUE WILL ENABLE A NEW CLASS OF DYNAMIC AND FUNCTIONAL MRI STUDIES TO BE PERFORMED. THE INCREASED PATIENT THROUGHPUT POSSIBLE WITH SUCH RAPID SCAN TIMES WILL OPTIMIZE THE COST- EFFECTIVENESS OF THE TECHNOLOGY, AN ESPECIALLY IMPORTANT CONSIDERATION IN TODAY'S COST-CONSCIOUS HEALTH CARE CLIMATE.