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Biomedical subjects

C G Harrison

Publications and source records attributed to C G Harrison.

6 recordsLinked to original sources
PubMed1996

A medical audit and patient survey of hysterectomies performed for menstrual disorders.

The aim of the study was to carry out an audit of 283 hysterectomies performed for menstrual disorders over a one year period, and to determine the satisfaction of the women concerned towards their treatment. The medical records of these patients were examined, and they were each sent a questionnaire, 69% of which were completed and returned. The most common presenting symptoms were menorrhagia and dysmenorrhoea. In 53% of cases no clinical abnormality was postulated and in 31% of cases no pathological abnormality was found. The preoperative clinical and pathological diagnoses were in agreement for 59% of patients. Over 90% of women were satisfied with the management of their case by their GP and the gynaecology outpatient clinic. The use of patient-controlled analgesia systems was associated with better post-operative pain relief than intramuscular injections. Thirteen percent of patients required blood transfusion; 21% suffered some form of postoperative complication, most of which were minor. Ninety-four percent of the women were pleased that they had undergone hysterectomy, and 76% wished that they had had the operation sooner. It was concluded that hysterectomy is perceived positively by patients and should not necessarily be considered as a last resort treatment for menstrual disorders.

Adult↗
PubMedDate not supplied

Magnetic field dependence of 1/T1 of protons in tissue.

It is well established that the spin-lattice magnetic relaxation rate 1/T1 of solvent protons in homogeneous protein solutions increases dramatically as the magnetic field is reduced well below the traditional NMR range. For a 5% solution of protein of 10(5) Daltons, for example, 1/T1 increases from about 50% above the pure solvent rate at 20 MHz to five times the solvent rate at 0.01 MHz. At higher fields, the effect of protein on the relaxation rate decreases progressively toward zero. 1/T1 of solvent in erythrocyte suspension behaves similarly, indicating that extracellular water has ready access to intracellular protein. We now report analogous data for samples of various mammalian tissues: we find that the data can be accommodated within the conceptual framework developed earlier for analyzing homogeneous protein solutions. It appears that tissue water probes the macromolecular composition and structure in a tissue-specific fashion. The variation of 1/T1 with field differs for each tissue, and its magnitude at low fields varies by more than a factor of three, far more than does the water content of the tissues. The relevance to contrast in NMR imaging is discussed.

Adipose Tissue↗
PubMedDate not supplied

In vivo 19F NMR imaging of liver, tumor, and abscess in rats. Preliminary results.

In vivo magnetic resonance imaging (MRI) has employed almost exclusively the proton because of its high gyromagnetic ratio and natural abundance relative to other nuclei. Recent research has focused on imaging using nuclei other than 1H, but has been limited by the decreased sensitivity and/or low biologic concentrations of the nuclei. Fluorine (19F), with a gyromagnetic ratio second only to that of hydrogen, is a theoretically attractive nucleus for MRI, but fluorine is present in only minute amounts in most tissues. Perfluorochemical emulsions (PFC), developed as blood replacement agents, appear to be safe vehicles for fluorine administration. We report our initial results of in vivo 19F magnetic resonance imaging of liver, tumor, and abscess in rats given exogenous fluorine.

Abscess↗
PubMedDate not supplied

Imaging of complex NMR spectra.

The Point Spread Function (PSF) in NMR imaging is the result of both the line broadening due to magnet field inhomogeneity and the intrinsic spectrum of the nucleus at resonance. In the case of proton imaging, the line broadening dominates the small chemical shifts and the spectral lines are not resolved. This is not generally the case with other nuclei having strong chemical shifts and the PSF then has a complex structure. During imaging, the complex PSF is convolved with the spatial distribution of the nucleus at resonance and this leads to halo artifacts which are dependent on the imaging technique employed. The images due to the ensemble of spectral lines can be separated in principle by deconvolution of the data with the PSF before reconstruction. In the special case where the complex PSF is spatially independent, it can be obtained from the Free Induction Decay (FID) data produced in the absence of a spatially encoding gradient field. This technique has been successfully applied to in-vivo imaging of exogenous perfluorocarbon material.

Animals↗