Radiofrequency (RF) surface coils are extensively used as receivers in magnetic resonance imaging (MRI) and spectroscopy (MRS) systems thanks to their high signal-to-noise ratio (SNR). For specific applications, the design of dedicated RF with a transverse (to coil’s plane) field pattern can be necessary. Such transverse-field constituted by several central linear (parallel or crossing) conduct...

One-dimensional stray field (STRAFI) profiles of 31P in phantoms containing, variously, calcium hydroxyapatite, calcium orthophosphate and cobaltous phosphate octahydrate were obtained in a STRAFI field of 11.7 T on a 19.6 T magnet at 206 MHz. The intrinsic spatial resolution with the apatite and orthophosphate samples was about 100 μm. The profile of the image from the paramagnetic cobaltous s...

As new medical applications of ultrasound emerge with operating frequencies in the hundreds of kilohertz to low megahertz region, it becomes more important to have convenient calibration methods for hydrophones in this frequency range. Furthermore, short diagnostic ultrasound pulses affected by finite amplitude distortion require that the hydrophone frequency response be known well below the ce...

The mean absolute brightness temperature of the diffuse radio background was measured as a function of frequency in a continuous band between 100 and 200 MHz over an effective solid angle of ∼ π str at high Galactic latitude. A spectral brightness temperature index of β = 2.5 ± 0.1 (αS = 0.5) was derived from the observations, where the error limits are 3σ and include estimates of the instrumen...

Table I. The different tiles for the benchmark image Q = 5 No tiles 8x8 4x4 1x32 1x1 Lena 344 K 346 K 350 K 345 K 433 K Baboon 484 K 490 K 504 K 497 K 704 K Airplane 274 K 276 K 279 K 279 K 332 K Pepper 387 K 390 K 397 K 392 K 501 K Q = 70 No tiles 8x8 4x4 1x32 1x1 Lena 8.34 K 9.55 K 12.6 K 10.9 K 38.9 K Baboon 31.8 K 32.8 K 35.7 K 34.3 K 60.7 K Airplane 9.27 K 10.5 K 13.8 K 12.3 K 39.6 K Peppe...

The maxim of the superscalar architecture is that higher performance can be achieved by executing multiple instructions simultaneously. This can be realized in hardware by using a centralized instruction window. We present the design and implementation of a centralized instruction window capable of out-of-order issue and completion of four instructions per cycle. A compact layout (6.4mm by 2.2m...

A new multifrequency (19-55 MHz) ultrasound biomicroscope with two-dimensional imaging and integrated Doppler ultrasound was evaluated using phantoms and isoflurane-anesthetized mice. Phantoms revealed the biomicroscope's lateral resolution was between 50 and 100 microm, whereas that of a conventional 13 MHz ultrasound system was 200-500 microm. This difference was apparent in the markedly high...

INTRODUCTION Transendoscopic miniprobes (TEMPs) have nowadays precise indications, but may become a diagnostic alternative to both radial and sectorial endoscopic ultrasonography (EUS) in the near future. PATIENTS AND METHODS From November 1996 to July 2004 we carried out 620 examinations using TEMPs (124 during the last 12 months in 2003, with currently a mean of 11 examinations/month). Twen...

The technique of Harmonic Motion Imaging (HMI) utilizes the localized stimulus of the oscillatory ultrasonic radiation force as produced by two overlapping beams of distinct frequencies, and estimates the resulting harmonic displacement in the tissue in order to assess its underlying mechanical properties. In this paper, we studied the relationship between the measured displacement and the gel/...