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Biomedical subjects

P Burger

Publications and source records attributed to P Burger.

64 records · Page 4Linked to original sources
PubMedDate not supplied

Dynamic range extension of cine velocity measurements using motion-registered spatiotemporal phase unwrapping.

A motion-registered spatiotemporal phase-unwrapping method for extending the dynamic range of cine magnetic resonance phase velocity measurements is presented. The interframe cardiac movement is estimated from the magnitude image derived from the velocity encoded raw data, which ensures that the phase signal is unwrapped in the temporal direction with reference to pixels belonging to the same anatomic flow region. An extra step of spatial phase correction is then used to further eliminate any residual errors. The combination of spatial and temporal information for phase unwrapping provides a robust way of extending the dynamic range of cine velocity data in the presence of large phase aliasing errors.

Algorithms↗
PubMedDate not supplied

Automatic enhancement, animation, and segmentation of flow in peripheral arteries from MR phase-shift velocity mapping.

The authors describe a technique for automatic enhancement, segmentation, and analysis of flow from MR phase shift velocity mapping. This method uses a specific flow related enhancement process to extract and localize the flow field within the image, followed by global flow analysis. By animation on low cost equipment (personal computers), this method can provide various ways of visualizing flow in vivo and its variation in different structures and lesions. Our preliminary results using this method for analyzing flow data in the aortic bifurcation of healthy volunteers are encouraging.

Aorta, Abdominal↗
PubMedDate not supplied

Examination of the extracranial carotid bifurcation by thin-section dynamic CT: direct visualization of intimal atheroma in man (Part 1).

Because carotid angiography has been shown to have limitations in the detection of intimal disease at the bifurcation, a new method of examination of the extracranial carotid artery has been developed using thin-section dynamic computed tomographic (CT) scanning. Carotid atheroma and thrombi can be imaged directly on these sections. The intimal lesions are uniformly hypodense with respect to the carotid arterial wall. Radiologic-pathologic correlation studies using human carotid arteries in a neck phantom confirm that these hypodense lesions are atheromas or thrombi. There is good correlation between CT cross-sectional images and cross-sectional postmortem artery sections. While a number of new computer-based methods of reformation of the carotid artery have been developed, consecutive thin slices through the carotid bifurcation display the pathologic lesions satisfactorily.

Carotid Arteries↗
PubMedDate not supplied

Opacification of epidural venous plexus and dura in evaluation of cervical nerve roots: CT technique.

Thin-section computed tomography (CT) after bolus high-volume, intravenous contrast enhancement of the cervical epidural and intervertebral foraminal venous plexus was undertaken in eight patients. Visualization of exiting cervical nerve root by opacification of the surrounding intervertebral plexus was evaluated in 38 foramina. Visualization was judged as excellent in 77% and good in 21%. Thus the nerves were seen satisfactorily in all but one foramen. As the CT scan parallels the long axis of the cervical roots as they pass through the intervertebral foramen, anatomic delineation of the root out to the level of the vertebral artery is excellent. A local widening of the root, which was thought to represent the dorsal root ganglion, was seen in most foramina examined. Excellent filling of the epidural plexus was seen in seven of eight subjects; good opacification was seen in the other subject. In no instance did the study fail to satisfactorily fill the epidural plexus in the cervical vertebral canal. This technique appears to be an excellent method for evaluating the cervical nerve roots and the epidural space.

Cervical Plexus↗
PubMedDate not supplied

Primary intracranial meningeal and spinal hemangiopericytoma: radiologic manifestations.

Meningeal hemangiopericytomas are rare but aggressive tumors. All eight patients in this series developed recurrences, three with distant metastases. In six patients a lytic destructive lesion of bone was evident. CT scans in three patients demonstrated diffusely enhancing lesions. No tumor calcification was present. In five of six patients angiography was characterized by multiple irregular tumor vessels, an intense prolonged blush, and the absence of early draining veins. Differentiation of these tumors from meningiomas is discussed.

Adult↗
PubMedDate not supplied

CT-guided stereotaxis using a modified conventional stereotaxic frame.

Computed tomographic (CT)-guided stereotaxic procedure have become established in a few major centers but a single optimal system has not yet emerged. At Duke University Medical Center, availability of a stereotaxic frame with design features that lend themselves to CT adaptation made modification of this unit, rather than construction of a new dedicated frame, cost-effective. As other centers may seek to modify available stereotaxic equipment in a similar way, this report documents the modifications ans the early clinical experience in four patients in whom CT-guided stereotaxic biopsy procedures were performed.

Adolescent↗