Three-dimensional computed tomographic angiography in the preoperative evaluation of cerebrovascular lesions.

Although three-dimensional computed tomographic angiography was developed as a screening tool for use in patients with suspected cerebrovascular disease, this imaging modality has also proven to be of value in surgical planning for patients with large or unusual vascular lesions of the brain. The three-dimensional images generated by this technique yield valuable information regarding the size and configuration of intracranial aneurysms and vascular malformations, the presence and extent of intra-aneurysmal thrombus, the relationship of the vascular lesion to other cerebrovascular or skeletal structures, aneurysm wall thickness, and the presence and orientation of an aneurysm neck. The use of three-dimensional computed tomographic angiography in representative cases of patients with large or unusual cerebrovascular lesions is presented. It has been our experience that this imaging modality displays anatomical information that is not readily available from standard, intra-arterial angiography, provides better detail for surgical planning than magnetic resonance angiography, and is less expensive than either of these other imaging modalities.

Three-dimensional computerized tomography angiography in the diagnosis of cerebrovascular disease.

Computer-generated three-dimensional reconstruction of the intracranial vascular system obtained by contrast-enhanced computerized tomography (CT) has been used in the diagnosis of 20 patients with known or suspected intracranial cerebrovascular disease. This technique allows visualization of the intracranial vasculature without exposing patients to the risks associated with intra-arterial angiography. The color prints and videotape images generated have been used to diagnose the presence of intracranial aneurysms, arteriovenous malformations, and venous angiomas. They have also been used to rule out structural abnormalities in patients with suspected intracranial vascular pathology and to screen patients with a strong family history of intracranial aneurysm. In 11 patients who underwent both three-dimensional CT angiography and intra-arterial angiography, the diagnostic correlation was 100%. No complications from the procedures or from incorrect diagnosis have been encountered. Although this technique requires further development and clinical evaluation, the authors' early experience with three-dimensional CT angiography suggests that this may become a valuable tool in the diagnosis of patients with cerebrovascular disease.

Computer-assisted three-dimensional reconstructions of [14C]-2-deoxy-D-glucose metabolism in cat lumbosacral spinal cord following cutaneous stimulation of the hindfoot.

We report on computer-assisted three-dimensional reconstruction of spinal cord activity associated with stimulation of the plantar cushion (PC) as revealed by [14C]-2-deoxy-D-glucose (2-DG) serial autoradiographs. Moderate PC stimulation in cats elicits a reflex phasic plantar flexion of the toes. Four cats were chronically spinalized at about T6 under barbiturate anesthesia. Four to 11 days later, the cats were injected (i.v.) with 2-DG (100 microCi/kg) and the PC was electrically stimulated with needle electrodes at 2-5 times threshold for eliciting a reflex. Following stimulation, the spinal cord was processed for autoradiography. Subsequently, autoradiographs, representing approximately 8-18 mm from spinal segments L6-S1, were digitized for computer analysis and 3-D reconstruction. Several strategies of analysis were employed: 1) Three-dimensional volume images were color-coded to represent different levels of functional activity. 2) On the reconstructed volumes, "virtual" sections were made in the horizontal, sagittal, and transverse planes to view regions of 2-DG activity. 3) In addition, we were able to sample different regions within the grey and white matter semi-quantitatively (i.e., pixel intensity) from section to section to reveal differences between ipsi- and contralateral activity, as well as possible variation between sections. These analyses revealed 2-DG activity associated with moderate PC stimulation, not only in the ipsilateral dorsal horn as we had previously demonstrated, but also in both the ipsilateral and contralateral ventral horns, as well as in the intermediate grey matter. The use of novel computer analysis techniques--combined with an unanesthetized preparation--enabled us to demonstrate that the increased metabolic activity in the lumbosacral spinal cord associated with PC stimulation was much more extensive than had heretofore been observed.

Use of computed tomography for a three-dimensional treatment planning system.

Computed tomography (CT) can generate a set of serial contiguous slices which form a volume of medical image data. We have developed new techniques for creating computer synthesized 3-D images directly from a volume encoded as a three-dimensional array. The operator can place the eye anywhere in object space to selectively view a portion of the volume from any angle. A set of volume processing tools have been recently developed to allow interactive manipulation of image data within the volume. These tools allow the system to be used for surgical planning, and craniofacial implant design.

Pediatric AIDS. Neuroradiologic and neurodevelopmental findings.

A group of 23 pediatric patients seropositive for HIV antibody were studied by computed tomography and evaluated neurodevelopmentally. Significant neurodevelopmental delays were found in over 95% of the patients studied. CT findings in six patients were normal and thirteen of 23 (57%) had prominence of the CSF spaces. Less frequent findings included calcifications in the basal ganglia and white matter. Cerebral mass lesions included one case of lymphoma and one case of hemorrhage. The CT findings in the pediatric age group differs from the adult population in that contrast enhancing inflammatory mass lesions are uncommon.

Mucosal nerves and smooth muscle relationships with gastric glands of the opossum: an ultrastructural and three-dimensional reconstruction study.

The precise anatomical relation by which autonomic nerve endings contact gastric epithelial cells to enhance the rate of gastric secretions is not fully understood. The aim of the present study was to clarify this issue by using the technique of serial section reconstruction of areas of the gastric mucosa. The work also explored the possibility of a functional role for a system of smooth muscle strands in the gastric mucosa that emanate from the muscularis mucosa, run in the lamina propria, and are associated in a unique manner with the gastric glands. Electron microscopic serial sections of the gastric mucosa were performed to visualize the entire limiting membrane of gastric epithelial cells to determine any nerve associations (especially varicose endings) with these cells. Evaluation of serial sections of five separate parietal cells showed that their basal membrane did not come in close contact (nearest distance 500 nm) with any nerve axon or varicosity. Moreover, the axons passing in the area of these cells ultimately showed varicose endings associated with smooth muscle cells in the adjacent connective tissue (often separated by only 20 nm), with mast cells or with vascular elements. Additionally, the lateral membrane of these five parietal cells did not contact any endocrine cell in the epithelium, although other parietal cells in the area were adjacent to endocrine cells. Chief cells in the immediate area also did not form any close associations with nerve varicosities. Random analysis of 5,000 additional epithelial cells in these sections showed no close associations to nerve elements with significant accumulations of neurosecretory vesicles (varicosities). Because of the observed existence of innervation to the smooth muscle strands in the area of the gastric glands, serial 1-micron epoxy sections of the gastric mucosa were prepared, and profiles of smooth muscle and gastric glands were entered into a computer-assisted reconstruction system. Three-dimensional reconstruction techniques were employed to reveal the existence of a unique association between the mucosal smooth muscle strands and the gastric glands. The muscle strands arose from the muscularis mucosa at regular intervals and became branched to form an intricate wrap around a series of gastric glands that empty into one gastric pit.(ABSTRACT TRUNCATED AT 400 WORDS)

A renal countercurrent system in marine elasmobranch fish: a computer-assisted reconstruction.

Computer-aided techniques were used to reconstruct the complex renal tubular system in the dorsal kidney region of a marine elasmobranch fish, the little skate (Raja erinacea), from a series of light micrographs of serial sections. It was established that five individual segments of one nephron, consisting of two loops and a distal tubule, are arranged in parallel within an elongated closed tissue sac. Capillaries, which form a network around these nephron segments, enter and exit this sac at the same end. This anatomical arrangement suggests that a complex renal countercurrent multiplier system may be important in fluid regulation in these fish.

Three-dimensional computer reconstruction of midbrain dopaminergic neuronal populations: from mouse to man.

A technique is described which has been used to quantitate the 3-dimensional configuration of the midbrain dopamine (DA) nuclei (cell groups A8, A9, and A10). This technique provides cell counting information, for example, the BALB/c mouse has approximately 25,000 midbrain DA neurons, the albino rat has about 40,000 neurons, and man (33 year old) has approximately 450,000 neurons. Furthermore, cell density topography maps were constructed which enable quantitation of the 3-dimensional cellular distribution. These topography maps revealed both similarities and differences across the three species examined. The number of midbrain DA neurons is known to be genetically determined and to decrease with aging. DA cell number is also related to motoric behavior and neurologic and perhaps psychiatric disease. The ability to quantitate DA regional cell densities represents a new technique which can be used to study the neurobiology of DA neurons and relate DA cell number to both normal and abnormal behaviors.