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Biomedical subjects

G M Ardran

Publications and source records attributed to G M Ardran.

At least 19 recordsLinked to original sources

Dysphagia due to cervical spondylosis.

Dysphagia from mechanical obstruction by osteophytes is rare. It is most important to investigate cases fully to rule out an alternative pathology. We describe a case of dysphagia resulting from cervical osteophytes interfering with epiglottic retrovertion. As far as we are aware, this has not been previously described.

Aged

Penetrameter cassette calibration to 400 kV and effects of extra-focal radiation when measuring tube filtration.

The penetrameter cassette, when used with suitable filters and calibrated against the same average wave form, can detect changes of less than 1 kV in the range 20-50 kV, 1 kV from 50-100 and from 1-4 Kv from 100-400 kV. Problems of calibration are discussed together with the necessity to use a suitable shutter with equipment which has a significant build-up and decay time during which the radiation quality may be varying. Extra-focal radiation does not normally present a significant problem in the measurement of kV, but when the penetrameter is used to measure inherent or total filtration extra-focal radiation can be a problem and may be similar in degree to the effects of varying target angles. When used to determine filtration, the generator used for calibration of the penetrameter and the one being measured should be adjusted to have the same target angle and similar degrees of extra-focal radiation by altering the size of the tube aperture as close to the focal spot as practicable. The results presented confirm the accuracy and convenience of the penetrameter for the measurement of kV and filtration over the extended range of energies.

Electronics, Medical

Gonad dose in cineurethrocystography.

The technical factors used for cineurethrocystography for the true lateral projection in females are given. The midline radiation dose has been measured with LiF TLD inserted into the vagina in 19 examinations. The average dose recorded was 148 mrad, the range being 50 to 306 mrad; the average number of cine frames exposed was 96. Data obtained using a Rando phantom indicated that the average ovary dose would be 30% greater than the mid-line dose since the near ovary receives a higher dose than the more distant one. The technique used for men is also given, the average gonad dose in six men being 123 mrad, range 56 to 243 mrad when simple lead foil gonad protection was used; the average number of cine frames was 107. The dose in one man without gonad protection was 1575 mrad for 112 cine frames. The results for both sexes compare favourably with those of others reported in the literature and with gonad doses recorded in typical IVP examinations.

Cineradiography

Constancy of radiation output during diagnostic x-ray expousers.

Variation in X-ray output and quality during a diagnostic exposure can be undesirable and may result in unnecessary dose to the patient. When significant build-up or decay periods are present errors will arise if factors obtained under steady-state conditions are employed to estimate the exposure. These parameters must be taken into account when calibrating X-ray generators. A variable speed spinning film device and a spectrometry system have been used to measure the variations under fluoroscopic and radiographic conditions for a number of generators. Variations in output due to filament heating, voltage supply and rectification, cable capacity and target pitting have been demonstrated. At low fluoroscopic currents, large surges and long decays have been observed; the significance of these effects is considered.

Fluoroscopy

Experimental production of forward dislocation in the human cervical spine.

Entire human cadaveric cervical spines with the basiocciput were subjected to load in a compression apparatus to simulate the clinical situation of forward dislocation. The movements were recorded by lateral cineradiography. Vertical load was measured by a potentiometric transmitter synchronised with each frame of the cineradiograph. The lower part of the spine was flexed and fixed, and the upper extended and free to move forward. Vertical compression then produced bilateral dislocation of the facets without fracture. If lateral tilt or axial rotation occurred as well, a unilateral dislocation was produced. The maximum vertical load was only 145 kilograms, and coincided with the rupture of the posterior ligament and capsule and the stripping of the anterior longitudinal ligament, but this occurred before dislocation. The low vertical load indicates a peculiar vulnerabiity of the cervical spine in this position and correlates well with the minor trauma often seen in association with forward dislocation.

Adult

A preliminary assessment of bladder distension in the treatment of enuretic children.

Urodynamic studies were performed in 22 enuretic children. Each child had previously been investigated to exclude gross psychological disturbance and organic disease and had been treated unsuccessfully in the past by conventional means. 16 of the 22 children showed evidence of bladder instability and were subjected to bladder distension. At follow-up, 4 children were in complete remission of symptoms, 6 had improved and 6 showed no change; the girls responded better than the boys. The interpretation of urodynamic studies, the significance of the results of bladder distension and the possible role of detrusor instability in the aetiology of enuresis are discussed.

Adolescent

The unstable bladder--fact or artefact?

100 patients, referred for urodynamic study, have had several cystometrograms performed at each examination, and the effect of filling at different rates and in different positions has been assessed. This has included pressure measurements carried out during "physiological" bladder filling. Bladder instability was found to be a highly consistent phenomenon, its detection being independent of filling rate or position of filling.

Adolescent

Urgency and urge incontinence of urine treated by prolonged bladder dystension: interim results.

Prolonged bladder distension has been used to treat patients with urgency and urge incontinence of urine. At follow-up varying from 14 to 24 months 17 out of 33 patients were symptom-free, 13 symptomatically improved and 3 unchanged. These results, as anticipated, are not so good as the initial early reported results, but are sufficiently encouraging for us to recommend prolonged bladder distension for the treatment of severe urgency and urge incontinence of urine.

Humans

Cinefluorography in the diagnosis of pharyngeal palsies.

(1) The aetiology of dysphagia may be difficult to diagnose when it presents without clinical signs or an associated clinical syndrome. (2) Pharyngeal palsies present in acute and chronic forms. (3) Cinefluorographic techniques are helpful in making an objective diagnosis of pharyngeal palsy. (4) Advice may be given to the patient on head and neck positions during swallowing that is based on the findings of the cinefluorographic examination, in order to alleviate symptoms. (5) Good fluoroscopy, preferably with video-tape recording facilities may be perfectly adequate provided that the diagnosis is considered at that time.

Adult

Distension therapy for the unstable bladder: later results including an assessment of repeat distensions.

51 patients with urgency and urge incontinence of urine and enuresis have been treated by prolonged bladder distension. At recent follow-up, 16 patients were symptom free, 25 substantially improved and 10 symptomatically unchanged, at a mean of 13 months after distension. 13 patients whose symptoms relapsed after a previous distension or who failed to obtain a satisfactory improvement have had a further distension for a more prolonged period. The early results in this group are not as good as for patients having first distensions, although 2 patients have become symptom free, and 6 have shown a substantial symptomatic improvement.

Adolescent