Interlaboratory comparison of ultrasonic backscatter coefficient measurements from 2 to 9 MHz.

OBJECTIVE: As are the attenuation coefficient and sound speed, the backscatter coefficient is a fundamental ultrasonic property that has been used to characterize many tissues. Unfortunately, there is currently far less standardization for the ultrasonic backscatter measurement than for the other two, as evidenced by a previous American Institute of Ultrasound in Medicine (AIUM)-sponsored interlaboratory comparison of ultrasonic backscatter, attenuation, and speed measurements (J Ultrasound Med 1999; 18:615-631). To explore reasons for these disparities, the AIUM Endowment for Education and Research recently supported this second interlaboratory comparison, which extends the upper limit of the frequency range from 7 to 9 MHz. METHODS: Eleven laboratories were provided with standard test objects designed and manufactured at the University of Wisconsin (Madison, WI). Each laboratory was asked to perform ultrasonic measurements of sound speed, attenuation coefficients, and backscatter coefficients. Each laboratory was blinded to the values of the ultrasonic properties of the test objects at the time the measurements were performed. RESULTS: Eight of the 11 laboratories submitted results. The range of variation of absolute magnitude of backscatter coefficient measurements was about 2 orders of magnitude. If the results of 1 outlier laboratory are excluded, then the range is reduced to about 1 order of magnitude. Agreement regarding frequency dependence of backscatter was better than reported in the previous interlaboratory comparison. For example, when scatterers were small compared with the ultrasonic wavelength, experimental frequency-dependent backscatter coefficient data obtained by the participating laboratories were usually consistent with the expected Rayleigh scattering behavior (proportional to frequency to the fourth power). CONCLUSIONS: Greater standardization of backscatter measurement methods is needed. Measurements of frequency dependence of backscatter are more consistent than measurements of absolute magnitude.

Comparison of Pueraria lobata with hormone replacement therapy in treating the adverse health consequences of menopause.

OBJECTIVE: Pueraria lobata (PL) is used as a traditional Chinese herbal remedy for menopausal symptoms, as well as an ingredient in preparations for conditions affecting menopausal women, such as osteoporosis, coronary heart disease, and some hormone-dependent cancers. The scientific basis for its action may be its action as a phytoestrogen. DESIGN: To examine the effects of PL in comparison with hormone replacement therapy (HRT) on lipid profile, sex hormone levels, bone turnover markers, and indices of cognitive function. For the study, 127 community-living, postmenopausal women aged 50 to 65 years were randomized to receive HRT (n = 43), PL (equivalent to 100 mg isoflavone; n = 45), or no treatment (n = 39) for 3 months. The following measurements were carried out at baseline and after 3 months for all participants: menopausal symptoms questionnaire; neuropsychological tests covering memory, attention, motor speed, and word-finding ability; quality of life (SF36); lipid profile; urinary deoxypyridinoline; dietary phytoestrogen intake and urinary phytoestrogen; estradiol; follicle-stimulating hormone; and luteinizing hormone. RESULTS: Only participants in the HRT group showed a mean reduction in cholesterol and low-density lipoprotein cholesterol that was significantly different from that of the control group. No significant changes in lipid profile or follicle-stimulating hormone and luteinizing hormone were observed in the PL group compared with the controls. However, both the HRT and PL groups showed an improvement in Mini-Mental State Examination score and attention span compared with the case of participants receiving no treatment. HRT and PL had different effects on cognitive function; HRT improved delayed recall, whereas flexible thinking seemed improved in the PL group. CONCLUSIONS: This study was unable to demonstrate a scientific basis for the use of PL for improving the health of postmenopausal women in general. However, the effect of PL on cognitive function deserves further study.