Biomedical subjects

A C Bergh

Publications and source records attributed to A C Bergh.

6 recordsLinked to original sources

PubMed1997

A new set of fiducial markers for MRI, CT and SPET alignment.

A set of fiducial markers for use in the alignment of MR, CT and SPET images is presented. The marker system consists of individually produced imprints of the external auditory meatus, a pair of plastic spectacle frames and three fiducial markers. The markers are filled with a suitable contrast agent, fixed into the imprints and screwed onto the spectacle frame just before examination. The reproducibility in positioning the marker system on the patient was evaluated by repeated MRI examinations of a volunteer. The fiducial markers could be repositioned with an accuracy of less than +/- 1.6 mm in the left-right and anterio-posterior directions and +/- 1.9 mm in the cranio-caudal direction (95% confidence interval). The marker system is inexpensive and easy to produce, taking less than 20 min to produce on the ward. Only a few minutes are required to fix the system prior to examination. It is comfortable for the patient, even during long examinations. In cases lacking visible intrinsic structures and external contours, fiducial markers provide a good means of alignment for image fusion. The marker system described here for the alignment of SPET, CT and MR images can be used on a routine basis without the invasive fixation of fiducial markers.

Brain↗

PubMed1994

Regional cerebral blood flow in normal pressure hydrocephalus: diagnostic and prognostic aspects.

Relative regional cerebral blood flow (rrCBF) was measured by single-photon emission tomography (SPET), using technetium-99m-d,l-hexamethylpropylene amine oxime (HMPAO) as flow tracer, in 23 patients with normal pressure hydrocephalus (NPH). 1000 MBq 99mTc-HMPAO was given intravenously and the rrCBF calculated as regional/cerebellar count level ratios. The patients were examined before and 3-12 months after ventriculoperitoneal shunt surgery. rrCBF was also determined in ten healthy aged matched volunteers who served as controls. The NPH patients had decreased rrCBF in the hippocampal regions and in the frontal and parietal white matter as compared to the controls. The frontal/parietal rrCBF ratio correlated with both psychiatric disability and the preoperative degree of incontinence. Decreased flow in frontal white matter, frontoparietal and hippocampal grey matter and a low frontalparietal grey matter flow ratio preoperatively correlated with improvement in both Mini Mental State score and psychiatric disability after shunt surgery. After shunt surgery the rrCBF increased in the mesencephalon, frontal grey and white matter, parietal white matter and hippocampus. The flow increase in hippocampal regions and frontal white matter correlated with improvement in psychiatric symptomatology. The results of this study regarding the frontal and hippocampal rrCBF patterns, and the clinical correlation, support the hypothesis that CBF changes in these regions are of pathophysiological and prognostic importance in NPH.

Adult↗

PubMed1994

A new method for the relative quantification of rCBF examined by 99Tcm-HMPAO SPECT.

A new method for the analysis of regional cerebral blood flow (rCBF) studies, the 'Min-Max' method, was compared with the conventional method, the 'Average' method. Regional CBF was examined by single photon emission computed tomography (SPECT) using 99Tcm-hexamethylpropyleneamine oxime (99Tcm-HMPAO). The two methods were used to quantify the rCBF in a population of patients with various dementia disorders, and in healthy controls. Results from a phantom were also used. In the Average method the average counts per pixel (cp-1) within irregular manually drawn regions of interest (ROIs) was registered. In the Min-Max method the minimum cp-1 and maximum cp-1 within rectangular ROIs were registered for white and grey matter, respectively. The relative rCBF (rrCBF) was calculated as the ratio between the regional and cerebellar values. The Min-Max method gave systematically lower values for rrCBF in the white matter, in both clinical studies, and in the phantom, compared to the Average method. No difference was found in the grey matter results. The variability in rrCBF in the phantom study was greater with the Min-Max method than with the Average method, but this effect was counteracted in the clinical studies by a smaller interobserver error. The average regional differences between patients and controls appeared greater with the Min-Max method than with the Average method. The Min-Max method proved to be more simple to execute, involved a smaller observer error, and with respect to ability to distinguish patients with dementia disorders from controls, it appears to function at least as well as the accepted Average method.

Adult↗

PubMed1994

Quantitative SPECT cisternography in normal pressure hydrocephalus.

Twenty-one patients with normal pressure hydrocephalus (NPH), 8 patients with various brain diseases with an element of hydrocephalus, and 7 patients with miscellaneous dementia disorders were investigated with quantitative radionuclide cisternography (RC) using single photon emission computerized tomography (SPECT). The total intracranial counts as well as the counts in the lateral and third ventricles were measured. All 15 NPH patients accessible for postoperative examination were improved after shunt surgery. In all groups the ventricular and total intracranial counts level increased during the measurement period but remained constant in distribution in each group. The NPH patients had a higher relative count value in the lateral and third ventricles compared to the patients with miscellaneous dementia disorders. The relative values in the third and lateral ventricles were predictive for the outcome of shunt surgery. Quantitative SPECT RC appears to be a useful diagnostic procedure in NPH investigations.

Adult↗

PubMed1993

Regional cerebral blood flow in multiple sclerosis measured by single photon emission tomography with technetium-99m hexamethylpropyleneamine oxime.

The regional cerebral blood flow (rCBF) in 19 patients with multiple sclerosis (MS), 10 with a relapsing remitting course and 9 with a progressive course, was examined by single photon emission computed tomography (SPECT) using technetium-99m hexamethylpropyleneamine oxime ([99mTc]-d,l-HM-PAO) as flow tracer. Nine age-matched volunteers served as controls. Low rCBF in the frontal grey matter correlated with neurological disability (p < 0.01), low frontal grey and white matter perfusion correlated with impaired cognitive functions (p < 0.02), and low rCBF in the occipital regions correlated with impaired visual functions (p < 0.03) in the MS population. A relationship was also found between reduced parietal white matter perfusion and the duration of the disease (p < 0.005). Patients with progressive MS had significantly reduced rCBF in the frontal grey matter compared with relapsing remitting MS patients and controls (p < 0.05). No other rCBF differences were found. As a diagnostic tool in MS, SPECT-[99mTc]-d,l-HM-PAO was found to be insensitive.

Adult↗

PubMed1990

Predictive value of quantitative cisternography in normal pressure hydrocephalus.

Twenty-five patients with normal pressure hydrocephalus (NPH) and 16 patients with cerebral atrophy were investigated by quantitative cisternography using anterior images of the head 3, 6 and 24 h after a lumbar injection of 200 MBq 99mTc DTPA (diethylene-triamine-penta-acetic acid). The activity in the lateral ventricles, basal cisterns, hemispheric convexities and total intracranial region was measured. Ratios between these regions/quantities were calculated. Fifteen of the NPH patients improved while 10 were unchanged after ventriculo-peritoneal shunt surgery. The ratio between ventricular and total intracranial activity (V/T) correlated positively with the degree of improvement after shunt surgery. All NPH patients with a V/T ratio higher than 32% improved after the operation but a V/T ratio less than 32% did not exclude the possibility of improvement. With regard to quantitative measurements, the radionuclide cisternography procedure can be reduced to imaging at 24 h.

Aged↗