Novel image processing and computer graphics techniques were developed to create three-dimensional (3D) models of vasculature from magnetic resonance (MR) angiographic images of the head or neck. Region growing was used to produce a mask that isolated the vascular signal in the MR angiographic data. The masked images were subjected to gradient-shaded volume rendering to create 3D views of the vasculature. The computer-derived model of intracranial vasculature was then merged with a 3D model of brain parenchyma derived from a set of MR images. The combined display of vascular and gyral anatomy may be useful for neurosurgical planning.

Brain↗

PubMedDate not supplied

Retrospective fusion of radiographic and MR data for localization of subdural electrodes.

Prior to epilepsy surgery, subdural electrodes are often implanted and monitored for a few days to identify the focus of abnormal electrical activity. During the implantation and subsequent brain resection, there may be uncertainty about the exact location of the electrodes with respect to features of brain anatomy such as specific gyral convolutions or lesions. In experiments with a phantom and patients, implanted electrodes were imaged with multiplanar skull radiographs (or CT scans). After retrospective registration with preimplantation MR data, the electrodes were mapped from these studies onto an MR-derived three-dimensional brain model. The resulting multimodality displays showed the relationship of the electrodes to brain anatomy. In one patient the position of each electrode with respect to a metabolic lesion was also displayed by mapping preimplantation PET data onto the same brain model. This new display of electrode positions may strengthen the interpretation of subdural electrical recordings and thereby reduce uncertainty in planning the resection of epileptic tissue.

Adult↗

PubMedDate not supplied

Lichen amyloidosus in Singapore.

Explore the source record for details and available documents.

Adolescent↗

PubMedDate not supplied

Three decades of tuberculosis in Singapore.

Tuberculosis (TB) mortality for the period 1955-1959 to 1985-1989 declined 87% from 72 to 9 per 100,000 in males, and 90% from 31 to 3 per 100,000 in females. The mean annual rate of decline of mortality was 6.8%. Older persons had a lower 4.2-5.2% decline annually compared to 14.1-16.0% in the 0-4 year age group. The incidence of TB declined 80% from 438 to 88 per 100,000 in males, and 71% from 152 to 43 per 100,000 in females over the period 1960-64 to 1985-89. The mean annual rate of decline in incidence was 5.9%. The lowest decline was observed in the children below 15 years (2.8-3.2%) and elderly persons 65 years and above (2.3-5.5%). Birth cohorts of 1945-49 and earlier had progressively higher mortality risks, but declining morbidity risks as they advanced with age. Singapore has overcome the early phase of the TB epidemic as evidenced by its relatively low rates among children and females and the low rates of extra-pulmonary TB and meningitis. The high incidence rates in old people are the residue of even higher rates experienced by this cohort of persons who experienced higher risks of infection in their early lives. At the prevailing rates of decline under the present conditions and control measures, TB will not be eliminated in Singapore over the next 50 years.

Adolescent↗