PubMed Health⌕ Search

Biomedical subjects

L Barnden

Publications and source records attributed to L Barnden.

4 recordsLinked to original sources
PubMed2000

Regional cerebral blood flow in fibromyalgia: single-photon-emission computed tomography evidence of reduction in the pontine tegmentum and thalami.

OBJECTIVE: To determine whether regional cerebral blood flow (rCBF) is abnormal in any cerebral structure of women with fibromyalgia (FM), following a report that rCBF is reduced in the thalami and heads of caudate nuclei in FM. METHODS: Seventeen women with FM and 22 healthy women had a resting single-photon-emission computed tomography (SPECT) brain scan to assess rCBF and a T1-weighted magnetic resonance imaging (MRI) scan to enable precise anatomic localization. Additionally, all participants underwent 2 manual tender point examinations and completed a set of questionnaires evaluating clinical features. SPECT scans were analyzed for differences in rCBF between groups using statistical parametric mapping (SPM) and regions of interest (ROIs) manually drawn on coregistered MRI. RESULTS: Compared with control subjects, the rCBF in FM patients was significantly reduced in the right thalamus (P = 0.006), but not in the left thalamus or head of either caudate nucleus. SPM analysis indicated a statistically significant reduction in rCBF in the inferior pontine tegmentum (corrected P = 0.006 at the cluster level and corrected P = 0.023 for voxel of maximal significance), with consistent findings from ROI analysis (P = 0.003). SPM also detected a reduction in rCBF on the perimeter of the right lentiform nucleus. No correlations were found with clinical features or indices of pain threshold. CONCLUSION: Our finding of a reduction in thalamic rCBF is consistent with findings of functional brain imaging studies of other chronic clinical pain syndromes, while our finding of reduced pontine tegmental rCBF is new. The pathophysiologic significance of these changes in FM remains to be elucidated.

Analysis of Variance↗
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↗
PubMed1982

Effect of renal transplantation on left ventricular function in hemodialysis patients.

The effect of renal transplantation on left ventricular function was evaluated in 14 patients with end-stage renal disease requiring maintenance hemodialysis. They had no apparent clinical evidence of heart disease. Ischemic heart disease was excluded by history, electrocardiography and radionuclide ventriculography. Echocardiography and radionuclide ventriculography were recorded in the interdialytic periods. Sixty-four per cent of the patients had abnormal left ventricular function despite adequate hemodialysis. Left ventricular function was reassessed within the first two months after successful renal transplantation. All parameters improved shortly after the transplantation. Cardiac index increased by an average of 0.76 +/- 0.11/min/m2 (P less than 0.001), stroke volume by 23.9 +/- 0.5 ml (P less than 0.001), ejection fraction by 9.7 +/- 1.9% (P less than 0.001), mean normalized posterior wall velocity by 0.17 +/- 0.06 second-1 (P less than 0.01), mean velocity of circumferential fiber shortening by 0.28 +/- 0.02 circle/second (P less than 0.001), and mitral valve diastolic closure rate by 17.2 +/- 2.3 mm/second (P less than 0.01). Our findings support the existence of a specific uremic cardiomyopathy which is a functional defect probably related to poorly dialyzed uremic toxins.

Adult↗