PatentsALERT

5600245

INSPECTION APPARATUS USING MAGNETIC RESONANCE

Yamamoto Etsuji; Ochi Hisaaki; Itagaki Hiroyuk; Onodera Yukari; Takeuchi Hiroyuk Akishima, JAPAN assigned to Hitachi Ltd; Hitachi Medical Corporati

An inspection apparatus using magnetic resonance includes magnetic field generators for generating a static magnetic field, a gradient magnetic field and a radio frequency magnetic field, respectively, a signal detector for detecting magnetic resonance signals from an inspected object, a computer for executing arithmetic operations for detection signals from the signal detector and an output device of the result of the arithmetic operations by the computer. The gradient magnetic field generator includes first and second gradient coils, the first gradient coil is a coil fixed to a magnet for generating a static magnetic field, the second gradient coil is a movable coil, and the magnetic field generated by the second gradient coil at a conducting portion of the magnet is offset by the magnetic field generated by the first gradient coil. According to this construction, an eddy current that occurs with the time change of the gradient magnetic field can be reduced.

5602476

ULTRA-FAST MR IMAGING DATA ACQUISITION SCHEME USING MIXED

BANDWIDTH DATA

Liu Haiying; Gullapalli Rao; Loncar Mark J Euclid, OH, UNITED STATES assigned to Picker International Inc

In a magnetic resonance imaging system, a read gradient scaler scales the amplitude and width of read gradients. A sampling rate control controls the sampling rate of the resonance signals received from corresponding magnetic resonance echoes. For example, when the amplitude of the gradient pulse is doubled and its width halved, the sampling rate of the resultant magnetic resonance signal is doubled, e.g., from a bandwidth of 32 MHz to a bandwidth of 64 MHz. In this manner, some echoes are read-out over a longer period of time with a lower bandwidth to produce lower signal-to-noise data lines; whereas, other echoes are much shorter and are read-out more quickly, but with a lower signal-to-noise ratio. The phase-encoding gradients are controlled such that the resultant data lines with the

lowest bandwidth have the lowest phase-encoding angles closest to the zero phase-encoding and the data lines with the highest bandwidth have the highest phase-encoding angles closest to the negative and positive maximum phase-encoding gradients. The data lines are sorted by phase encode angle and bandwidth and reconstructed into an image representation.

5602477

NUCLEAR MAGNETIC RESONANCE FREEZING SENSOR

McCarthy Michael J; Reid David S Davis, CA, UNITED STATES assigned to The Regents of the University of California

A non-invasive apparatus and method for determining changes in the enthalpy of an object undergoing a freezing cycle using nuclear magnetic resonance imaging (NMRI) techniques. Enthalpy is determined from the position of the ice interface of said object or, alternatively, from the liquid/solid ratio of the object.

5602478

REDUCTION OF RF FIELD DISTURBANCE IN MAGNETIC

RESONANCE APPARATUS

Salloway Anthony J; Gilderdale David J Northamptonshire, UNITED KINGDOM assigned to GEC-Marconi Limited

In a magnetic resonance apparatus including a transducer positioned in the examination region of the apparatus, the transducer is connected with equipment outside the examination region by way of a lead which is grounded to signals of the frequency of the RF field applied to a subject in the examination region to excite magnetic resonance in the subject, at a distance along the lead from the transducer equal to a quarter wavelength at the RF field frequency (or an odd multiple thereof). Distortion of the RF field due to loading by the transducer is thereby reduced. The transducer may, for example, be a microphone or loudspeaker, e.g. incorporated in an intercom or active noise reduction arrangement, or a sensor for sensing a condition of a patient being examined.