The inherent sensitivity of multiple gradient-echo sequences to the chemical shift is exploited to rapidly map muscle water frequency shifts caused by ultrasonic heating. The use of multiple echoes is shown to offer several advantages over single gradient-echo approaches previously proposed for temperature measurement. An increase in the effective bandwidth significantly reduces aliasing proble...

OBJECTIVE To investigate if magnetic resonance spectroscopy (MRS) is the best Magnetic Resonance (MR)-based method when compared to gradient-echo magnetic resonance imaging (MRI) for the detection and quantification of liver steatosis in diabetic patients in the clinical practice using liver biopsy as the reference standard, and to assess the influence of steatohepatitis and fibrosis on liver f...

PURPOSE We developed and evaluated clinically T1-weighted three-dimensional gradient-echo magnetization transfer (MT) sequences for contrast-enhanced MR imaging of the brain. METHODS A short-repetition-time, radio frequency-spoiled, 3-D sequence was developed with a 10-millisecond MT pulse at high MT power and narrow MT pulse-frequency offset, and the enhancing lesion-to-normal white matter b...

PURPOSE To assess the value of an added gradient echo in the same pulse sequence with a T1-weighted spin echo for determining the presence of an abnormal fluid collection in the temporomandibular joint with no additional imaging time. MATERIALS AND METHODS Using a standard T1-weighted sequence used in cine temporomandibular joint imaging, a readout gradient reversal was added and the resultin...

PURPOSE To determine optimal MR gradient-echo sequences for the visualization of calcium in neurologic MR. METHOD The dependence of signal intensity and image contrast on the imaging parameters repetition time, echo time, flip angle, and spoiling were measured for hydroxyapatite samples. Calculations of signal intensity were shown to correspond to these measures. RESULTS Optimum detectabili...

A prospective study was undertaken on 204 consecutive patients comparing low flip angle gradient-echo and T1-weighted spin-echo techniques in the MR evaluation of cervical extradural disease. Four patient groups were studied with varying gradient-echo TEs (6 or 13 msec) and flip angles (10 degrees or 60 degrees). Images were evaluated independently for contrast behavior and anatomy, then direct...

Background An MRI-compatible 12-lead ECG platform, equipped with MRI-gradient induced-voltage removal hardware and magneto-hydrodynamic voltage removal software [1], was previously applied to physiological monitoring and synchronization of cardiac imaging of patients inside MRI. This approach had limited success for highduty-cycle [(total Gradient-ramp-time per R-R)/(R-R time) >20%] MRI sequenc...

Twenty canine elbows were examined by low-field MRI. The objective of this study was to compare five magnetic resonance sequences: High Resolution Gradient Echo in the sagittal plane, XBONE T2 in the sagittal plane, Spin Echo T1 in the sagittal plane, Spin Echo T1 in the dorsal plane and 3D SST1 and XBONE T1 in the transverse plane, and to determine which sequences have the highest diagnostic v...