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Biomedical subjects

B Condon

Publications and source records attributed to B Condon.

47 records · Page 3Linked to original sources
PubMed1986

Use of magnetic resonance imaging to measure intracranial cerebrospinal fluid volume.

Magnetic resonance imaging was used to measure intracranial extraventricular and ventricular cerebrospinal fluid (CSF) volume. In 10 normal subjects lateral ventricular and extraventricular intracranial CSF volumes were 25.3 +/- 4.6 ml (mean +/- SD) and 97.6 +/- 6.6 ml, respectively (total 122.8 +/- 38.7). These volumes were measured in 4 patients and the results were: 11.0 ml ventricular volume, 68.7 ml total cranial CSF in the patient with benign intracranial hypertension; 606.6 ml ventricular, 174.1 ml total in the patient with hydrocephalus due to a blocked ventriculo-peritoneal (V-P) shunt; 83.4 ml ventricular, 108.5 ml total in the patient with normal pressure hydrocephalus; and 52.7 ml ventricular, 181.0 ml total in the patient with cerebral atrophy due to Alzheimer's disease. The technique gave highly reproducible results (SD less than 5.7% of mean value). It may be useful in differential diagnosis and as an objective means of monitoring therapy or progress in conditions such as cerebral atrophy, hydrocephalus, and benign intracranial hypertension.

Adolescent↗
PubMed1983

A physical comparison of two fixed-angle emission tomographic cardiac imaging systems.

Two 7-pinhole tomographic imaging systems for large and small field-of-view gamma cameras were compared with a standard rotating slant-hole system in terms of planar resolution and resolution with depth. Other measurements include the determination of the depths of the reconstructed planes, image miniaturization and scintislice area variation with depth, the effect of scatter on resolution and the variation in resolution across the reconstructed plane. The pinhole sensitivities and the relative reconstructed sensitivities with depth were also measured. The rotating slant-hole system is found to have better depth resolution, a better scatter correction, has more uniform reconstructed sensitivities, is easier to position over the patient but requires significantly longer data acquisition times than the 7-pinhole system.

Heart↗
PubMed1982

Myocardial imaging with dipyridamole: comparison of the sensitivity and specificity of 201Tl versus MUGA.

Myocardial imaging was performed at rest and after dipyridamole infusion using 201Tl and 99Tcm - gated blood pool studies (MUGA). Of 38 patients studied, 21 had coronary artery disease (CAD) and 17 were normal. With 201Tl imaging, 19 of 21 patients with CAD (sensitivity 88%) showed perfusion defects during dipyridamole. Of 17 normals 6 (specificity 65%) showed clear perfusion defects during dipyridamole. With MUGA, 2 of 15 patients with CAD (sensitivity 13%) developed abnormal wall motion during dipyridamole; both patients developed ST depression greater than 1 mm. Of 10 normals none developed abnormal wall motion. Twenty six of 38 patients developed angina during dipyridamole, which was reversed by aminophylline in 24 of 26. We suggest that dipyridamole infusion is effective for 201Tl-perfusion imaging, and easily performed, but is not suitable for MUGA studies where ischaemia is the required endpoint.

Aminophylline↗
PubMed1982

Radionuclide evaluation of valvular regurgitation.

A non-invasive nuclear medicine technique for the assessment of aortic and mitral regurgitation may be of importance in the management of patients with valvular disease. Rigo et al (1979) introduced a method based on measuring the ratio of the left ventricular stroke volume to the right ventricular stroke volume from radionuclide equilibrium gated blood-pool images of the heart. In this paper we report our results using this technique. They indicate that caution should be exercised, and in particular that methods used to define the ventricular regions of interest must be carefully examined.

Aortic Valve Insufficiency↗
PubMed1977

Ataralgesia in outpatient urology. Clinical evaluation.

The combination of fentanyl citrate (Sublimaze) and diazepam (Valium) was evaluated for efficacy of analgesia, sedation, and safety in 1,008 predominately outpatient urologic procedures. These procedures included prostate biopsies, basket extractions of ureteral calculi, internal urethrotomies, and cystourethroscopies. Ninety-two per cent were judged to be successful with regard to adequate tranquilization and relief of pain. No detrimental effects were seen with the recommmended method and dosage. This drug combination provides the clinician with an effective and safe alternative to local, general, or spinal anesthesia for many routine urologic procedures and allows them to becom true office procedures.

Adolescent↗
PubMedDate not supplied

Digital mapping of multi-parameter contrast functions in magnetic resonance (MR) imaging using a standard MR computer system and digital display.

A technique is described which utilises the full analysis and display capabilities of a commercial MRI system to produce digital maps of multi-parameter functions produced by MR contrast theory. The technique is utilised to determine the effects of nominating specific overall scan times on the optimum solutions as produced by the theory and it is shown that different solutions are obtained when the theory is applied using typical clinical constraints. The digital mapping approach is potentially of great value in prospectively determining pulse timing parameters to produce optimum contrast images, in producing contrast maps to aid retrospective image interpretation, and as a training aid for clinicians inexperienced in the interpretation MR images.

Computer Graphics↗
PubMedDate not supplied

MR relaxation times of cerebrospinal fluid.

A review of 15 recent publications purporting to provide the relaxation times of CSF reveals a considerable disparity in the quoted results, by a factor of five in terms of T1 (range 1,000 to 5,500 ms) and by a factor of 16 for T2 (range 166 to 2,640 ms). In this article measurements are performed independently on both a spectrometer and an imager. The results indicate that for CSF T1 is greater than 3,000 ms and T2 is approximately 2,000 ms at 6 MHz. The vast differences in relaxation behaviour between CSF and other body tissues have considerable clinical implications and present profound diagnostic opportunities. The application of this knowledge to ventriculography, myelography, and image contrast methodology is discussed.

Cerebrospinal Fluid↗
PubMedDate not supplied

Is cranial CSF volume under hormonal influence? An MR study.

We used magnetic resonance to investigate the hypothesis that premenstrual neurological symptoms are due to cerebral oedema and brain swelling. Total cranial and lateral ventricular CSF volumes were measured midcycle and premenstrually in 20 women with a normal menstrual cycle, and similar measurements were made 2 weeks apart in 10 postmenopausal women and 10 men. Total cranial CSF volume increased premenstrually in 19 women. The mean premenstrual increase was by 11.5 ml. There was not a significant difference between those women who were taking an oral contraceptive and those who were not. The CSF volume did not change significantly on repeat measurement in men and postmenopausal women. The CSF changes observed reflect a reduction in brain volume and do not support cerebral swelling as the cause of premenstrual neurological symptoms.

Adult↗