Saline infusion contrast intrauterine sonographic assessment of the endometrium with high-frequency, real-time miniature transducer in normal menstrual cycle: a preliminary report

Fabrication and evaluation of a single-element Bi0.5Na0.5TiO3-based ultrasonic transducer

This paper discusses the fabrication and characterization of a single-element ultrasonic transducer with a lead-free piezoelectric active element. A piezoelectric ceramic with composition of 0.88Bi(0.5)Na(0.5)TiO(3)-0.08Bi(0.5)K(0.5)TiO(3)- 0.04Bi(0.5)Li(0.5)TiO(3) was chosen as the active element of the transducer. This composition exhibited a thickness coupling coefficient (kt) of 0.45, a dielectric constant of 440 (at 1 kHz), and a longitudinal piezoelectric coefficient (d(33)) of 84 pC·N(-1). To make the transducer, the ceramic was sandwiched between an epoxy-tungsten backing layer and a silver epoxy matching layer. An epoxy lens was also incorporated into the transducer's design to focus the ultrasound beam. The focused transducer with a center frequency of about 23 MHz demonstrated a -6-dB bandwidth of 55% and an insertion loss of -32 dB; the -20-dB pulsed length was measured to be 150 ns. A phantom made of copper wires (30 μm in diameter) was utilized to investigate the imaging capability of the transducer. The results indicated that the fabricated transducer, with a lateral resolution of 260 μm and a relatively high depolarization temperature, could be considered as a candidate for replacement of lead-based ultrasonic transducers.

A pilot evaluation of saline sonohysterography for postmenopausal bleeding with thickened endometrium

The aim of this study was to assess the clinical and cost implications of pilot introduction of saline sonohysterography for postmenopausal bleeding with thickened endometrium (>or= 5 mm), at the Royal Glamorgan Hospital. The investigation was attempted in 48 patients who were found to have a thickened endometrium (>or= 5 mm) on transvaginal ultrasound scanning. The attempt was successful in 45 patients (93.8%). Failures were due to (1) cervical stenosis and (2) leakage of saline from the cervix. Difficult catheterisation of the cervix causing pain was encountered in a minority of cases. Two-thirds of patients were found have focal lesions and were booked for hysteroscopic resection. These patients included 30 with polyps, which were precisely described in all of them. In view of this low complication rate and high accuracy, the technique was integrated as a standard method of investigation for postmenopausal bleeding at the hospital.