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Biomedical subjects

W S Andrus

Publications and source records attributed to W S Andrus.

5 recordsLinked to original sources

Interpretation of roentgenograms via interactive television.

The diagnostic quality of roentgenographic images transmitted by interactive television was evaluated. A series of 100 kidney, ureter and bladder, chest, and bone radiographs were read individually by five radiologists, both on direct viewing and on viewing a monitor image of the television signal. The latter was transmitted by microwave a distance of 28 miles, including four transmission legs. Analysis in terms of receiver operating characteristic curves and critical tables indicated that the television interpretations were of acceptable accuracy, in view of the participants' inexperience with teleradiology.

Bone and Bones

Remote interpretation of chest roentgenograms.

A series of 98 chest films was interpreted by two physicians on the basis of monitor display of the transmitted television signal representing the roentgenographic image. The transmission path was 14 miles long, and included one active repeater station. Receiver operating characteristic curves were drawn to compare interpretations rendered on television view of the image with classic, direct view interpretations of the same films. Performance in these two viewing modes was found to be quite similar. When films containing only hazy densities lacking internal structure or sharp margins, were removed from the sample, interpretation of the remaining films was essentially identical via the two modes. Since hazy densities are visible on retrospective examination, interpretation of roentgenograms at a distance via television appears to be a feasible route for delivery of radiologic services.

False Negative Reactions

Hearing and para-airport children.

Audiometric screening was carried out on 3,322 elementary and high school students living in the vicinity of Logan International Airport, Boston, in an effort to determine whether noise from aircraft had any measurable effect on their hearing. Followup examinations and additional data on children failing the screening examination made it possible to classify the hearing losses as conductive, sensorineural, or mixed. The incidence of bilateral sensorineural or mixed hearing loss in the group living directly under flight paths or immediately adjacent to runways was not significantly different from the overall average. In normal subjects, the average sensorineural gap, a newly defined measure of high-tone loss, was not found to be significantly affected by the degree or duration of exposure to aircraft noise.

Adolescent

Tympanometric pattern classification in relation to middle ear effusions.

Tympanometric evaluation using an otoadmittance meter and X-Y plotter was performed on 129 ears of 70 children with history of recurrent acute otitis media, or evidence otoscopically of persistent middle ear effusion, or both. Myringotomy, performed immediately following the tympanometric procedure, confirmed the presence or absence of effusion. Following myringotomy, tympanometric patterns, as shown by susceptance and conductance tracings at 220 and 660 Hz, were identified and middle ear pressures and otoadmittance peak values were determined. These findings were compared and criteria were developed which best determined the presence or absence of effusion. The results revealed the following: 1) High negative middle ear pressure is not necessarily a reliable indicator of middle ear effusion. 2) Tympanometry can be used reliably as an indicator of effusion. A combination of pattern classification and susceptance criteria enabled correct prediction of effusion in 93% of these children. One pattern at B660 was found to be pathognomonic of effusion. 3) In general, otoadmittance at 660 Hz appears to be a better indicator of effusion than 220 Hz.

Acute Disease