New Patents XXIX

Novel complexes of paramagnetic ions and com- pounds bearing long acyl chains have been syn- thesized as magnetic resonance imaging contrast agents. These novel liposoluble contrast agents may be administered alone, or with lipids, suspending agents or other additives. The lipids may be in the form of liposomes, micelles or lipid emulsions. The contrast agents of the invention have particular use in magnetic resonance im- aging of the liver, blood pool and reticuloen- dothelial system.

5312755

CONTRAST RESOLUTION TISSUE MIMICKING PHANTOMS

FOR NUCLEAR MAGNETIC RESONANCE IMAGING WITH

STABLE NMR PROPERTIES

Ernest L Madsen, Joseph C Blechinger, Gary R Frank assigned to Wisconsin Alumni Research Foundation

Tissue mimicking phantoms for NMR imagers are produced having a base tissue mimicking material enclosed within a sealed container. The base tissue mimicking material is a gel solidified from a mixture of agar, animal hide gelatin, water, glycerol, and anti-bacterial agents such as n-propanol, p-methylbenzoic acid, and formal- dehyde. The formaldehyde also serves to cross link the animal hide gel and thereby raise the melting point of the tissue mimicking material to a temperature above normal ambient tem- peratures. This base tissue mimicking material is stable both in dimensions and NMR properties over long periods of time. Contrast resolution in- clusions are formed within the base tissue mimicking material which have Tl, T2, or both which differ from the corresponding values for the base tissue mimicking material, thereby al- lowing these inclusions to be imaged and dist- inguished from the surrounding material. The inclusions simulate tumors in normal tissue, and are preferably formed in a variety of sizes down to very small diameter spherical objects which are at or beyond the imaging capability of the NMR imaging apparatus. Inclusions which are stable in size, shape and NMR properties over time while in direct contact with the base tissue mimicking material without the need for a bar- rier are formed of the same solidified gel material as the base tissue mimicking material but dif-

fering in the dry weight concentration of agar. Several sets of inclusions may be formed so that each set will have a different level of contrast with the base tissue mimicking material.

5313162

APPARATUS FOR THROUGHFLOW NMR

SPECTROSCOPY, ESPECIALLY FOR CELL SUSPENSIONS

Albert De Graaf, Ulrich Probst, Heerlen, Netherlands assigned to Forschungszentrum Julich GmbH

A combined fermenter and measuring tube for NMR throughflow spectroscopy on cell suspen- sions in which the measurement tube has a capacity of 3 to 20 ml in the measuring zone of the magnet and a fermenter is a premagnetiza- tion reservoir of greater cross section of a capacity of at least 100 ml in the repolarization range. A liquid circulator is provided to provide a throughflow rate of 5 to 250 ml/s in the measuring tube.

5313163

SAMPLING-RING SATURATION PULSE FOR TWO-DIMENSIONAL

MAGNETIC RESONANCE SELECTIVE EXCITATION

Christopher Hardy, Edward J Nieters assigned to General Electric Company

A method for suppressing sampling-ring ar- tifacts produced by spiral-scan-based 2D selec- tive excitation pulses, such as a those exciting a pencil-shaped region, employs a 2D annular saturation pulse followed by a gradient crusher lobe which dephases the transverse magnetiza- tion in the annular region. The annular satura- tion pulse is itself based on a spiral k-space trajectory having a limited number of cycles and a small outer radius, and is designed to saturate magnetization of tissue of the subject correspon- ding to the artifact rings of an excitation region while not affecting a central region. The annular saturation pulse may also be reshaped to limit the peak RF power to levels currently used for clinical MR imaging, while preserving band- width and the 2D excitation profile.