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...

Mobile lithium ions in a cubic garnet Li7La3Zr2O12 (Al-stabilized) were studied using 7Li NMR spectroscopy for membrane and powder samples, the latter of which was ground from the membrane. Lithium diffusion in a micrometer space was measured using the pulsed-gradient spin-echo 7Li NMR method between 70 and 130 °C. When the observation time (Δ) was shorter than 20 ms, the echo attenuation showe...

The spatial specificity of functional hemodynamic responses was examined by simultaneous mapping of BOLD changes and quantitative changes in cerebral arterial blood volume (DeltaCBV(a)) across the cortical depth in cats (n=7) during 40-s visual stimulation. Studies were performed at 9.4 T using the recently developed, non-invasive magnetization transfer (MT)-varied gradient-echo (GE) fMRI techn...

In Project HeartBeat!, a longitudinal study of cardiovascular disease risk factors in healthy children and adolescents, 3 samples of 40, 80, and 182 echocardiograms, respectively, were randomly selected and reread to evaluate intraobserver and interobserver variabilities and comparability between measurements of field echocardiographic technicians and reference readings at Texas Children's Hosp...

In Project HeartBeat!, a longitudinal study of cardiovascular disease risk factors in healthy children and adolescents, 3 samples of 40, 80, and 182 echocardiograms, respectively, were randomly selected and reread to evaluate intraobserver and interobserver variabilities and comparability between measurements of field echocardiographic technicians and reference readings at Texas Children’s Hosp...

Venous oxygen saturation (Y(v) ) in cerebral veins and the cerebral metabolic rate of oxygen (CMRO(2)) are important indicators for brain function and disease. Although MRI has been used for global measurements of these parameters, currently there is no recognized technique to quantify regional Y(v) and CMRO(2) using noninvasive imaging. This article proposes a technique to quantify CMRO(2) fro...

This paper presents a new assessment of four approaches to acoustic echo cancellation in the presence of non-linear echo. The comparison is performed with algorithms that are configured to give equivalent performance under linear-only echo conditions, thereby giving a more meaningful assessment. We also compare the effect of non-linear echo to that of noise and show that, whilst performance dif...

Echolocating horseshoe bats respond to flight-speed induced shifts in echo frequency by adjusting the frequency of subsequent calls. Under natural conditions, Doppler effects may force the frequency of a returning echo several kilohertz above the original emission frequency. By lowering subsequent call frequencies, the bat can return echo frequencies to within a narrow spectral bandwidth to whi...