Abstract: A magnetic resonance imaging apparatus (A) generates a uniform magnetic field, causes gradient fields transversely thereacross, excites resonance in nuclei within the image region, receives radio frequency signals from resonating nuclei, and reconstructs images representative thereof. Electrodes (30) monitor the cardiac cycle of a patient (B) being imaged and an expansion belt (32) monitors the respiratory cycle. During a magnetic resonance imaging scan, noise signal wave forms or spikes are superimposed on the cardiac cycle signal. A noise spike detector detects noise spikes. Specifically, a comparator (48) compares each wave form received from the electrodes with properties of a cardiac signal, such as the slope. When the comparator determines that a noise wave form is being received, it gates a track and hold circuit (52). The track and hold circuit passes the received signal except when gated by the comparator.

Abstract: A patient is disposed on a patient couch (A) and positioned longitudinally and vertically to bring a region of interest within the patient into a gap between a pair of magnetic pole pieces (20, 22). Magnetic field driver(s) (50', 50, 52) generates a magnetic field through a U-shaped ferrous member (B) connected with the pole pieces and through the gap therebetween. The U-shaped ferrous member extends below the gap such that open access is provided to the patient from above. Shielding coils (62, 64, 66) are disposed between the U-shaped ferrous portion and the gap to compensate for distortion of the magnetic field in the gap attributable to magnetic flux through the U-shaped member. Magnetic resonance is excited in the region of interest of the patient between the pole pieces and magnetic resonance signals emanating therefrom are received, such as with a crossed elliptical quadrature coil (72).

Abstract: A magnetic resonance or other diagnostic imaging scanner (A) is connected with an image reconstruction module (B) for reconstructing diagnostic images. An integrated expert system (C) selects scan parameter settings for conducting the scan such that utility of the image is optimized for the intended diagnosis. A keyboard (12) receives subject and intended diagnostic application data such as the age of the patient, the region of the patient to be imaged, the anticipated size of the lesion, and the like. A first expert system (10) derives appropriate constraints on values for each performance index and priorities for each performance index from the subject and intended application data. The performance indices include contrast, resolution, scan suration, and the like. A scan parameter estimator look-up table (14) is addressed by the performance index constraints and priorities and retrieves corresponding estimated scan parameters.

Abstract: A magnetic resonance imaging apparatus (A) generates a uniform main magnetic field, gradient fields transversely thereacross, excites resonance in nuclei within an image region, receives radio frequency signals from the resonating nuclei, and reconstructs images representative thereof. Electrodes (30) monitor the cardiac cycle of a patient (B) being imaged and an expansible belt (32) monitors the respiratory cycle. A carrier signal from a generator (52) is modulated with the respiratory signals. The modulated carrier signals are combined (60) with the cardiac signals and converted to a light signal by a light source (62). A fiber optic cable (36) conducts the light signals to a light receiver (70). Band pass filters (72, 100) separate the received cardiac and respiratory encoded carrier signals. A zero detector (80) provides a scan initiation signal in response to a preselected portion of the cardiac cycle.