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B Hutton

Publications and source records attributed to B Hutton.

10 recordsLinked to original sources
PubMed2000

Validation of fully automatic brain SPET to MR co-registration.

Fully automatic co-registration of functional to anatomical brain images using information intrinsic to the scans has been validated in a clinical setting for positron emission tomography (PET), but not for single-photon emission tomography (SPET). In this paper we evaluate technetium-99m hexamethylpropylene amine oxime to magnetic resonance (MR) co-registration for five fully automatic methods. We attached six small fiducial markers, visible in both SPET and MR, to the skin of 13 subjects. No increase in the radius of SPET acquisition was necessary. Distortion of the fiducial marker distribution observed in the SPET and MR studies was characterised by a measure independent of registration and three subjects were excluded on the basis of excessive distortion. The location of each fiducial marker was determined in each modality to sub-pixel precision and the inter-modality distance was averaged over all markers to give a fiducial registration error (FRE). The component of FRE excluding the variability inherent in the validation method was estimated by computing the error transformation between the arrays of MR marker locations and registered SPET marker locations. When applied to the fiducial marker locations this yielded the surface registration error (SRE), and when applied to a representative set of locations within the brain it yielded the intrinsic registration error (IRE). For the best method, mean IRE was 1.2 mm, SRE 1.5 mm and FRE 2.4 mm (with corresponding maxima of 3.3, 4.3 and 5.0 mm). All methods yielded a mean IRE <3 mm. The accuracy of the most accurate fully automatic SPET to MR co-registration was comparable with that published for PET to MR. With high standards of calibration and instrumentation, intra-subject cerebral SPET to MR registration accuracy of <2 mm is attainable.

Algorithms↗
PubMed1995

Mercaptoacetate-induced feeding is impaired by central nucleus of the amygdala lesions.

Systemic administration of mercaptoacetate (MA) blocks beta oxidation of fatty acids and stimulates food intake. The present experiment examined MA-induced feeding in rats with bilateral lesions of the central nucleus of the amygdala (CNA) and sham-operated controls. Food intake was measured for 6 h immediately following i.p. injection of 400, 600, or 800 mumol/kg of MA or saline. Feeding was also measured in these rats in response to 2-deoxy-D-glucose (2DG) (100, 200, and 300 mg/kg, SC), a glucose analogue that competitively inhibits glucose utilization. We found that CNA lesions blocked feeding in response to all three doses of MA. Feeding in response to 2DG was significantly reduced, but not abolished, by the lesion. These findings suggest that the CNA is a crucial component of the neural pathway for feeding in response to MA and may also participate in 2DG-induced feeding.

Amygdala↗
PubMed1991

Effects of tracer blood measurement noise on glucose metabolic rate estimation.

Tracer kinetic modeling with Positron Emission Tomography (PET) requires measurements of the time-activity curves in both plasma (PTAC) and tissue (TTAC) to estimate physiological parameters. However, the estimation usually ignores the measurement noise in plasma tracer activity curves. The accuracy and reliability of the physiological parameters estimated by ignoring such noise are not well understood. In this paper, computer simulations were performed to investigate the influence of input measurement noise on the accuracy of estimates. The results show that input measurement noise causes considerable variability in the parameter estimates.

Blood Glucose↗
PubMed1988

Infant apnoea: a home monitoring programme.

A home monitoring programme for infants, thought to be at high risk of cot death, has been conducted in Auckland for the past five years. It has included infants who have experienced an apnoea thought to have been a life-threatening event, infants of very low birth weight, and siblings of infants who died of cot death. The supervision of the 84 infants referred to the programme in 1985 are discussed. The 77 referrals for presumed apnoea resembled the population of cot deaths in Auckland, being predominantly Maori--of low birth weight--between one and four months of age and being identified in the winter months. The mean age of occurrence of the last apnoea was 4 months. There were no deaths, but in 60% of the infants further apnoea was considered to occur and half of these infants required stimulation to recommence breathing. In 11 infants an underlying pathology was later identified as the cause of the initial apnoeic events. Hospital facilities for the investigation and supervision of these infants are inadequate in Auckland at present. The establishment of a fully integrated service for the care of infants at high risk of dying from a cot death is an urgent priority.

Apnea↗
PubMed1987

Endometrial blood flow measured by xenon 133 clearance in women with normal menstrual cycles and dysfunctional uterine bleeding.

Endometrial blood flow was measured through the menstrual cycle in nonpregnant women (28 studies of 17 women with normal menstrual cycles and 32 studies of 20 women with dysfunctional uterine bleeding) with use of a clearance technique in which 100 to 400 microCi of the gamma-emitting isotope, xenon 133 in saline solution was instilled into the uterine cavity. The mean (+/- SEM) endometrial blood flow in normal cycles was 27.7 +/- 2.6 ml/100 gm/min, with a significant elevation in the middle to late follicular phase, followed by a substantial fall and a secondary slow luteal phase rise that was maintained until the onset of menstruation. There was a significant correlation between plasma estradiol levels and endometrial blood flow in the follicular but not the luteal phase. Blood flow patterns in women with ovulatory dysfunctional bleeding were similar to normal, except for a significantly lower middle follicular rate. Women with anovulatory dysfunctional bleeding exhibited exceedingly variable flow rates.

Adult↗
PubMed1987

An evaluation of two inert gas clearance techniques for measurement of endometrial blood flow in women.

Two methods utilizing inert gas clearance for the measurement of endometrial blood flow in non-pregnant women have been assessed and compared. A Krypton-85 rebreathing technique allowed measurement of superficial flow by means of an intrauterine semiconductor beta-detector probe. Intrauterine instillation of high specific activity Xenon-133 in small volumes of saline allowed endometrial flow measurement by gamma camera recording of the rate of clearance. Both these methods permitted calculation of absolute rates of flow and comparison of cyclical changes. Direct comparison of the techniques in the same women, and repeatability studies have shown good agreement, with calculated rates of absolute endometrial blood flow varying within the range 14-60 ml per 100 g tissue per minute. Vaginal blood flow measured simultaneously was always significantly lower (36-64%) than endometrial flow.

Adult↗