Biomedical subjects
A A Chambers
Publications and source records attributed to A A Chambers.
Persistent trigeminal artery: unusual associated abnormalities.
Multiple cases of vascular abnormalities associated with the persistent trigeminal artery or a variant thereof are presented. A persistent otic artery variant is the only known such case in the literature.
Cranial and intracranial tuberculosis.
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Intracranial blood clot volume and geometric parameters determined from CT images.
A method of determining intracranial blood vlot volumes from CT images data is presented. This technique avoids dependence on regular geometric volume approximations. Studies are presented on phantoms of known volume (ranging from 3.5 to 108 cm3) but with varying size, shape, and density relative to the surrounding medium. For a wide range of differential densities across the boundary, these phantom results indicate that volumes may be calculated to an accuracy generally better than +/- 2 cm3. A series of clinical cases, principally hypertensive intracranial hemorrhages, have been studied to demonstrate the technique. Three-dimensional axes, which allow clot localization relative to cerebral anatomy, are defined using the anterior/posterior falx attachment points and the dorsum sellae. Clot volume, center of mass, vector of clot expansion, and shift of anatomical structures are determined. Correlation of these data with clinical outcome and surgery is discussed.
Iatrogenic carotid-cavernous fistula following Fogarty catheter thromboendarterectomy. Case report.
A case of iatrogenic carotid-cavernous fistula secondary to a Fogarty catheter thrombectomy is presented. The literature and seven previously reported cases are reviewed.
Pericollicular syndromes.
Five cases of pericollicular focal hemorrhages are presented with a description of their effect on vision and consciousness. Loss of vision, loss of consciousness, extraocular muscle dysfunction, mutism, and dyslexia may result from expansive lesions near the collicular plate.
Cerebral vascular lesions: infarction, hemorrhage, aneurysm, and arteriovenous malformation.
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Neuroradiology of sellar and parasellar lesions with emphasis on computerized tomography (CT).
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Neurofibromatosis and intracranial arterial occlusive disease.
Two cases of neurofibromatosis and intracranial arterial occlusive disease are reported. The radiographic and clinical features of these and twelve previously reported cases are reivewed.
Calcification in a chromophobe adenoma. Case report.
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Thrombosed giant middle cerebral aneurysms.
Two giant thrombosed aneurysms of the middle cerebral artery are reported with a review of the pertinent literature. A tortuous channel through the thrombus results in an unusual and characteristic angiogram. Mechanisms involved in the formation of this lesion are discussed.
Outlet obstruction of the fourth ventricle in sarcoidosis.
Central nervous system sarcoidosis and its varied neuroradiological manifestations are reviewed. Two cases of mechanical obstruction secondary to sarcoid granulomata at the outlet of the fourth ventricle are described.
Trigeminal artery connection to the posterior inferior cerebellar arteries.
An example of the internal carotid artery supplying the posterior inferior cerebellar artery directly is reported. The direct PICA supply comes from a trigeminal trunk. There was no basilar artery opacification. An embryological explanation is given.
Midline anterior atlas clefts: CT findings.
Anterior atlas clefts (AACs) are rare developmental variants that may mimic fractures. Due to the potential severe implications of craniocervical junction trauma, expeditious differentiation between a Jefferson burst fracture and a congenital cleft is essential in trauma patients. Three cases of AAC are presented. Two cases demonstrated incidental AACs; the third case was associated with a Jefferson burst injury. Computed tomography is most helpful in evaluating the integrity of the atlas; however, plain radiography or pluridirectional tomography are best for evaluating displacement of the lateral masses of C1 in relation to C2.
An evaluation of the performance characteristics of different types of collimators used with the EMI brain scanner (MKI) and their significance in specific clinical applications.
The characteristics of various types of collimators have been studied systematically for the EMI Mark I brain scanner. The degree of collimation ranged from the 13-mm adjacent A and B slices to 3-mm separated slices. Multiple phantom studies (including variable density immiscible liquid interfaces) have been performed to evaluate the effect of collimation on (a) the line-spread function, (b) the change in effective absorption number, and (c) volume averaging. Effects associated with the technique settings involving the kVp, the mA, and the scan time were also investigated. The results of TLD dose measurements as a function of collimation are presented. The significance of collimation in specific clinical studies involving small, fairly well-circumscribed lesions is discussed.
Why not the eighth nerve? Neurovascular compression--probable cause for pulsatile tinnitus.
Carotid arteriograms on three patients with unilateral pulsatile tinnitus demonstrated an ipsilateral atypical trigeminal artery extending from the cavernous portion of the internal carotid artery to form the posterior inferior cerebellar artery. Illustrations and a dissection of a human fetus with a similar finding show this artery crossing the cochlear nerve near its insertion in the pons. Evidence is presented suggesting that neurovascular compression of the eighth nerve is the source of pulsatile tinnitus in these patients.
Cranial epidermoid tumors: diagnosis by computed tomography.
Using seven illustrative cases, the authors discuss the computerized tomographic (CT) appearance of cranial epidermoid tumors. These tumors are of low density (-2 to +10 EMI units), seldom show calcification, and do not enhance with contrast medium. Their differentiation from dermoid tumors and craniopharyngiomas is also discussed.