Reduced MR acquisition time with the CROCUS technique

Improved field of view-reducing gradient insert: artifacts and application to cardiac imaging

An improved homogeneity-spoiling local gradient insert has been constructed and built into the patient bed to reduce its impact on bore size and setup time. It allows the field of view to be reduced without introducing aliasing artifacts. Image quality and artifacts were evaluated for pulse sequences relevant to cardiac imaging. The utility of the insert is demonstrated by a contrast-enhanced perfusion study, in which the reduced field of view allowed a 25% increase in resolution and one more slice to be imaged per heartbeat. J. Magn. Reson. Imaging 1999;10:209-215.

Can MRCP replace ERCP?

Magnetic resonance cholangiopancreatography (MRCP) has replaced direct cholangiography and pancreatography in many instances. Its complete noninvasiveness and flexibility are less onerous for patients. For the use of screening as well as scrutiny, MRCP has played an important role in diagnosing various pathologies in this field. The usefulness of MRCP is not limited to anatomical evaluations; it can also yield physiologic and functional information. From a cost-performance basis, MRCP is undoubtedly superior to direct methods. Coupled with a cutting-edge MR system, MRCP has the potential to limit the use of invasive transpapillary and percutaneous methods merely to interventional purposes. In the near future, the emergence of interventional MR scanners will make MRCP even more competitive, and the replacement will be accelerated.

Homodyne detection in magnetic resonance imaging

Magnetic detection of complex images in magnetic resonance imaging (MRI) is immune to the effects of incidental phase variations, although in some applications information is lost or images are degraded. It is suggested that synchronous detection or demodulation can be used in MRI systems in place of magnitude detection to provide complete suppression of undesired quadrature components, to preserve polarity and phase information, and to eliminate the biases and reduction in signal-to-noise ratio (SNR) and contrast in low SNR images. The incidental phase variations in an image are removed through the use of a homodyne demodulation reference, which is derived from the image or the object itself. Synchronous homodyne detection has been applied to the detection of low SNR images, the reconstruction of partial k-space images, the simultaneous detection of water and lipid signals in quadrature, and the preservation of polarity in inversion-recovery images.