Biomedical subjects

F H Chan

Publications and source records attributed to F H Chan.

4 recordsLinked to original sources

PubMed1992

Measurement of human BAERs by the maximum length sequence technique.

The traditional brainstem auditory evoked response (BAER) measurement technique (ensemble averaging) is time-consuming and is not acceptable for some time-critical clinical applications. In the paper the application of a pseudorandom binary sequence, the maximum length sequence, to human BAER measurements is examined. This technique permits a faster click rate to stimulate the test subject, and obtains a higher signal-to-noise ratio (SNR) response through deconvolution. When compared with conventional averaging, the method can result in an improved SNR or in faster measurement of BAER. The theory of the technique and the experimental setup are presented, and theoretical analysis on the SNR improvement by this technique against averaging is also given. Actual measurements of BAER on both humans and cats indicate that this technique is effective, especially when the measurement time is not too long, or the number of trials is not too large.

Algorithms↗

PubMed1991

Visual evoked potential measurement by maximum length sequence technique.

The maximum length sequence (MLS) technique is applied to improve data collection of a clinically important long latency visual potential. Given a limited time for measuring the response and with low number of stimulus presentation, the MLS technique exceeded the conventional method of ensemble averaging in attaining a higher signal-to-noise ratio (SNR). The theoretical consideration of such improvement is developed along with the system implementation. Typical examples of the results obtained in a human subject are presented.

Algorithms↗

PubMed1979

The changing perinatal and maternal outcome in chorioamnionitis.

Chorioamnionitis is difficult to detect clinically, but its recognition in those at risk is essential. A retrospective study of 140 patients from among 26,129 deliveries was conducted over a 2-year period. The findings suggest that in modern obstetric practice, both perinatal and maternal complications associated with chorioamnionitis (particularly sepsis) are infrequent problems. Four neonatal deaths occurred but no infants died of sepsis. There were no maternal deaths, but 38 patients developed postpartum infections. Cesarean section did not appear to improve either perinatal or maternal outcome. With the use of appropriate modern antibiotics, extraperitoneal cesarean section and cesarean hysterectomy are probably no longer indicated. Not all neonates born out of a microbiologically contaminated intrauterine environment required antibiotic therapy, however, and individualization is recommended.

Amnion↗

PubMed1976

An ultrasonogram display system using a natural color scale.

The gray scale display used in B scan ultrasonography limits the perceptibility of clinically useful information. Presentation in color can increase perceptibility, but current color displays have no natural scale and may have the fault of a discrete color spectrum. The continuous heated-object color spectrum solves these problems. To produce a display using this spectrum, we have built an inexpensive system to adapt the scan converter output of a gray scale ultrasonograph to a commercial color television.

Adult↗