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.

Hematoporphyrin derivative, a fluorogenic substance, tends to accumulate at higher levels in most tumor tissues after intravenous injection. These properties provide a potential application for the detection of malignant tumors. We report the development and in vitro evaluation of an instrument designed to excite and detect low levels of hematoporphyrin derivative fluorescence emitted by tumor cells in the bladder after hematoporphyrin derivative administration. The light source of the instrument for specific hematoporphyrin derivative excitation is at a wavelength of 405 nanometers. Optical fibers for both the excitation and detection of fluorescence were bundled in a single 7 French ureteral catheter which can be inserted into a standard cystoscope. The fluorescence is initially detected as an electrical signal which is amplified and then converted into an audio signal. The interference of the cystoscope illuminating white light to the fluorescence signal is eliminated by a phase-sensitive electronic circuit. The instrument thus allows simultaneous viewing of the bladder and detection of hematoporphyrin derivative fluorescence produced from tumor tissues. In vitro testings using hematoporphyrin derivative solutions on filter paper indicated that the instrument detects as little as 30 nanograms per milliliter of hematoporphyrin derivative and has relatively low noise levels from normal tissues. The utility of this instrument for hematoporphyrin derivative photodetection of small tumors and carcinoma in situ in bladder is currently under clinical evaluation.

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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.