Biomedical subjects
D Pang
Publications and source records attributed to D Pang.
Some biochemical actions of carnitylcholine, a neuromuscular blocking agent.
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Acute cerebellitis: case report and review.
We report a case of acute cerebellitis in a 7-year-old male presenting with headache, vomiting, ataxia and life-threatening hydrocephalus requiring emergent placement of an external ventricular drain. Unlike earlier reported cases which did not provide radiographic correlation of this disease, this report documents changes in the cerebellum with serial magnetic resonance and computer tomography scans. The signs, symptoms and differential diagnosis of this rare, self-limiting condition are briefly discussed.
Multiple epidural hematomas following ventriculoperitoneal shunt.
Although extra-axial hematomas are a well-known complication of ventricular shunting, epidural hematomas are uncommon in this setting. We report an unusual case of multiple epidural hematomas in a patient with hydrocephalus treated by ventriculoperitoneal shunt. The patient became symptomatic 5 days after shunting and required craniotomy for evacuation of one of the hematomas. The literature is reviewed and treatment discussed.
Temperature field estimation using electrical impedance profiling methods. II. Experimental system description and phantom results.
An electrical impedance tomography system has been developed and tested for the purpose of thermal imaging. Since impedance changes with temperature, images of impedance subtracted from normothermic baselines will provide a map of temperature data. A system was designed to be operational at 10-50 kHz and to utilize 16 external electrodes around the periphery of a tissue-equivalent phantom encompassing the region of interest. These electrodes serve as current sources for the 5 mA constant-current inputs and are also used for reading differential voltages. Hyperthermia treatments for cancer require that internal thermometry probes be inserted into the tumour volume. Linear arrays of electrodes with thermometry tracks for micro-dimension thermometry serve this function, as well as providing localized voltage measurements in the region of interest. The embedded temperature sensors provide a quality assurance and calibration standard for the linear arrays in reconstruction of impedance profiles. Results of transient heating experiments with conductive and ultrasound heating are shown where image reconstruction is performed using a finite element model. Temperature predictions in these studies were accurate to better than 1 degree C on average when using information from surface electrodes combined with internal linear arrays. Maximum temperature errors, however, was found to be > 5 degrees C which suggests that further noise reduction during data acquisition and improvements in the reconstructions algorithms are needed.
Embolization of intramedullary arteriovenous malformations of the spinal cord.
Intramedullary spinal cord arteriovenous malformation (AVM) can be a devastating disease. It is not usually amenable to surgery without producing severe neurologic deficit. Previously, the risk of cord ischemia was considered a contraindication to therapeutic embolization. Three patients with intramedullary spinal cord AVMs were examined and treated using polyvinyl alcohol foam, mixed with Gelfoam in two cases. In all three cases there was marked improvement, in two to complete normalcy and in the other to near-normalcy. Successful therapy involves the appropriate angiographic mapping, choice of embolus size and composition, and challenge of function by either test occlusion or long perfusion with contrast material.
Intrasellar and suprasellar paraganglioma: CT and MR findings.
We present the CT and MR findings of an intrasellar and suprasellar paraganglioma in a 17-year-old girl. Paragangliomas in this location are rare. The lesion had several imaging features characteristic of paragangliomas including marked enhancement after contrast and multiple vascular flow voids.