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Biomedical subjects

G Glover

Publications and source records attributed to G Glover.

At least 19 recordsLinked to original sources
PubMed1992

Seasonality of admissions in the psychoses: effect of diagnosis, sex, and age at onset.

A summer peak was found in first admissions to hospitals in England and Wales between 1976 and 1986 for both affective psychoses and schizophrenia, but not for neurotic conditions or personality disorders. There was no significant relationship between age at first admission and season of admission. The summer peak was most prominent for mania, where it was present in both sexes; for schizophrenia, it was present only in females. These findings suggest that schizophrenia in females, and mania in both sexes, have some aetiological or precipitating factor in common.

Adult↗
PubMed1991

Schizophrenia after prenatal exposure to 1957 A2 influenza epidemic.

The birth dates of schizophrenic inpatients in eight health regions in England and Wales were reviewed for any effect of the 1957 A2 influenza epidemic. 5 months after the peak infection prevalence, the number of births of individuals who later developed schizophrenia was 88% higher than the average number of such births in the corresponding periods of the 2 previous and the next 2 years. This finding is in accordance with a study from Helsinki and with clinical and neuropathological evidence of aberrant fetal brain development in the pathogenesis of schizophrenia.

Adult↗
PubMed1991

A reduced power selective adiabatic spin-echo pulse sequence.

We introduce a selective adiabatic pulse sequence suitable for generating selective spin-echoes for both MR imaging and spectroscopy. The technique is simple; one uses the echo generated by any pair of identical selective adiabatic inversion pulses. The nonlinear phase across the slice is compensated perfectly by the second pi pulse. This compensation is immune to RF inhomogeneity and nonlinearity. For imaging applications, we concentrate on a reduced-power version of the pulse sequence in which time is traded off variably for RF amplitude in the presence of a time-varying gradient. This technique, known as variable-rate excitation, mildly degrades the off-resonant slice profile when applied to amplitude-modulated pulses. We present theoretical explanations and experimental results that show that the variable-rate adiabatic pulses are immune to off-resonant degradation of the magnitude normally encountered in MR imaging.

Brain↗
PubMed1991

Rapid in vivo proton shimming.

A rapid and completely automated method of adjusting the magnetic field (B0) homogeneity for in vivo proton spectroscopy and imaging is described. B0 inhomogeneity maps are generated by a gradient-recalled echo pulse sequence in which the frequency dispersion is chosen to eliminate the effects of the fat/water chemical shift. Low-order shim values are derived by magnitude-weighted least-squares fits to the B0 maps and automatically applied as DC offsets to the X, Y, and Z gradient amplifiers. Imaging with chemical shift selective saturation is used as a measure of the efficacy of the technique. Results indicate that AUTOSHIM improves the overall homogeneity: however, local high-order field distortions which cannot be corrected by linear gradients are generated by certain air/tissue and bone/tissue morphology. In such cases a "Zoom SHIM" may be applied over a limited region of interest for local homogeneity improvement at the expense of other regions. It is suggested that such scans are a necessity for recording the homogeneity during clinical MR spectroscopy.

Algorithms↗
PubMed1991

The morbidity of salvage surgery following conventional radiotherapy and continuous, hyperfractionated accelerated radiotherapy (CHART).

A comparison was made of the morbidity of surgery for loco-regional recurrence in patients with advanced cancer of the head and neck region following continuous hyperfractionated accelerated radiotherapy (CHART), after conventional radiotherapy, and also in a group following surgery only as the primary treatment. Post-surgical morbidity occurred in 14 (77%) of the 18 patients treated with CHART, of whom 11 (78%) required a further surgical procedure. In the conventional group, morbidity occurred in 14 (58%) of the 24 patients, of whom 9 (64%) required further surgery. Finally, in the surgical group morbidity occurred in 13 (48%) of the 27 patients, of whom 7 (54%) required further surgery. Because of the many factors that may influence the chance of morbidity and of the small number of cases, considered statistical analysis is not meaningful and there must be caution in the interpretation of results. When allowance is made for the greater frequency of more advanced tumors and for sites in the oropharynx and oral cavity, where procedures associated with greater risk of complication were performed, the morbidity seen after surgery was performed upon CHART patients appeared to be no greater than when conventional radiotherapy had been given. As expected, the surgery only group showed less morbidity than either of the radiotherapy groups.

Adult↗
PubMed1988

Valvular regurgitation: dynamic MR imaging.

Cine magnetic resonance (MR) imaging is a new technique that combines short repetition times, limited flip angles, gradient refocused echoes, and cardiac gating. This technique has a temporal resolution of up to 32 time frames per cardiac cycle and accentuates signal from flowing blood. Cine MR images of 56 valves in 27 patients were evaluated and compared with either Doppler echocardiograms or cardiac catheterization images. An area of decreased signal that correlated spatially and temporally with regurgitant blood flow was seen in all instances in which valvular incompetence was demonstrated on either Doppler echocardiograms or cardiac catheterization images (20 valves). This abnormality was seen in nine of 36 cases without valvular incompetence. Cine MR imaging may be sensitive to turbulence and thus sensitive to valvular regurgitation.

Aortic Valve Insufficiency↗
PubMed1987

Two-second MR images: comparison with spin-echo images in 29 patients.

MR images can be obtained with a 2-sec scan time when an extremely short repetition rate (22 msec), limited flip angle (30 degrees), and gradient refocused echoes are used. Comparison of 415 such images obtained in 29 patients with routine T1-weighted (TR 500, TE 25) and T2-weighted (TR 2000, TE 80) images showed that images free of respiratory artifacts could be obtained in all patients. Although abdominal organs were well seen with 2-sec scan time, overall evaluation of these organs was better on routine T1-weighted images. Vascular structures, however, were seen as well or better on the 2-sec images in 60% of cases. The images were extremely sensitive to field nonhomogeneity, and metallic artifact was exaggerated in five patients with surgical clips. Two-sec MR images provide a rapid method of localizing abdominal organs for further evaluation. The sensitivity to blood flow may assist in the assessment of vascular patency.

Adrenal Glands↗