Patent application number | Description | Published |
20090009168 | System and method for minimizing MRI-imaging artifacts - Methods of, and systems for, simultaneously compensating for external-magnetic-field inhomogeneity as well as radiofrequency magnetic-field inhomogeneity in an MRI system. In one method embodiment, a pulse sequence is applied when the transmitter-reference frequency is delivered on resonance. The pulse sequence includes radiofrequency pulses which may be applied at arbitrary-excitation-flip angles that are not necessarily 90° degrees. The pulse sequence also includes spin-locking pulses applied in concert with a refocusing-composite pulse. In another method embodiment, a pulse sequence is applied when the transmitter-reference frequency is delivered off resonance. This off-resonance-pulse sequence includes radiofrequency pulses which may be applied at arbitrary-excitation-flip angles that are not necessarily 90° degrees. Sandwiched between the excitation-flip angles are at least two off-resonance-spin-lock pulses applied at an inverse phase and frequency from each other. | 01-08-2009 |
20090273343 | REDUCING IMAGING-SCAN TIMES FOR MRI SYSTEMS - Provided are methods and systems for rapid MRI imaging-scanning that provides 2D or 3D coverage, high precision, and high-temporal efficiency, without exceeding SAR limits. In one embodiment, a pulse sequence process is performed that includes a T | 11-05-2009 |
20100264920 | SPIN LOCKED BALANCED STEADY-STATE FREE PRECESSION (SLSSFP) - A spin locked balanced steady-state free precession (slSSFP) pulse sequence combines a balanced gradient echo acquisition with an off-resonance spin lock pulse for fast MRI. The transient and steady-state magnetization trajectory is solved numerically using the Bloch equations and is shown to be similar to balanced steady-state free precession (bSSFP) for a range of T2/T1 and flip angles, although the slSSFP steady-state could be maintained with considerably lower RF power. In both simulations and brain scans performed at 7 T, slSSFP is shown to exhibit similar contrast and SNR efficiency to bSSFP, but with significantly lower power. | 10-21-2010 |
20100282258 | METHOD AND APPARATUS FOR PROVIDING PULSES INHALATION OF 17O2 FOR MAGNETIC RESONANCE IMAGING OF CEREBRAL METABOLISM - Prior approaches have delivered O | 11-11-2010 |
20110028828 | T1 RHO MAGNETIC RESONANCE IMAGING FOR STAGING OF HEPATIC FIBROSIS - Methods for diagnosis of fibrotic diseases, staging of fibrotic diseases and monitoring treatment of fibrosis. The presence of fibrotic tissue is detected. First, a T | 02-03-2011 |
20120019245 | CEST MRI METHODS FOR IMAGING OF METABOLITES AND THE USE OF SAME AS BIOMARKERS - The CEST effect for various neurotransmitters and energy metabolites in the brain and muscles and various endogenous metabolites in the liver, brain, and myocardium are imaged using MR imaging to illustrate a unique CEST effect that may be used to monitor the concentration of the metabolite and hence to characterize and monitor various disease states in the body correlated to the concentration of that metabolite. By adjusting the timing, amplitude, and length of the RF pulse as well as other parameters of the CEST pulse sequence to address the unique chemical shifts and exchange rates of the target, new targets with unique characteristics may be acquired using CEST MR imaging. | 01-26-2012 |
20130147477 | ENDOGENOUS MAGNETIZATION CONTRAST IN MRI - An endogenous source of magnetic resonance image contrast of biological tissues is provided by modeling a conventional magnetization transfer (CMT) spectrum using z-spectral data and generating magnetization transfer ratio maps from the magnetization transfer spectrum at a frequency of interest. A contribution by the CMT spectrum from the z-spectral data is removed and a direct water saturation component is modeled using the z-spectral data with removed CMT spectrum (z-spectral). When this modeled direct water saturation component contribution is removed from the z-spectral, then the remaining z-spectra reflects new contrast due to chemical exchange saturation transfer (CEST) and magnetization transfer/exchange effect from aliphatic protons probably associated with labile proteins, peptides and lipids, named as novel magnetization transfer (NMT). This technique can be used to illustrate subtle changes in biological tissue as a result of diseases states, provide better visibility of brain white matter plaques, provide improved CEST contrast, provide better visualization of proteins, peptides, and lipids in biological tissue using NMT contrast, improve segmentation of white matter and gray matter in brain images, and the like. | 06-13-2013 |
20140213887 | CEST MRI METHODS FOR IMAGING GLUTAMINOLYSIS IN CANCER - CEST imaging technique and MR scanning are used as an MRI method for measuring glutaminase mediated tumors. The method takes advantage of the fact that glutamine does not exhibit a significant Chemical Exchange Saturation Transfer (CEST) effect while glutamate does. In accordance with this method, one first obtains a glutamate CEST MRI map of the area of a tumor. L-glutamine (nontoxic up to several millimolar level) or glutaminase blocker is then injected and a post injection Glutamate CEST map is obtained. The difference in the spatial maps indicates the level of expression of glutaminase in the tumor. | 07-31-2014 |