Biomedical subjects
Publications and source records attributed to G H Roberson.
A full radiological evaluation of patients who sustained traumatic injuries to the spine may be difficult to obtain due to the danger associated with manipulation. Computed tomography offers a new modality for simple and accurate evaluation; valuable information may be gained without the use of invasive methods.
The authors report a technique to precisely localize a fistulous opening in the carotid artery. The patient is heparinized and a Prolo catheter is introduced into the internal carotid artery and inflated distal to the approximate site of the fistula. Heparinization allows the balloon to be inflated long enough to obtain and analyze high-quality angiography film without fear of thromboembolism generated by the temporary balloon occlusion. Contrast material injected through the Prolo catheter proximal to the balloon reveals a small segment of cavernous carotid artery between the inflated balloon distally and the fistula proximally. The venous structures are now only faintly opacified and cannot obscure the morbid anatomy of the exact fistulous tear in the carotid artery. If the balloon is placed exactly opposite to the site of the fistula, a standing, stagnant column of dye forms a cast of the cavernous, petrous, and cervical carotid artery. Once the fistula is localized with this method, it may be obliterated by any therapeutic means preferred. If the Prolo catheter is used for intraluminal occlusion, then a transfemoral contralateral carotid angiogram is done before the heparin is reversed to confirm that the balloon has not been placed proxial to the fistula.
Sixteen cases of spontaneous dissection of the cervical internal carotid artery (6 verified) are described. The mean age was 45 years. The clinical picture varied from simply headache and a bruit to hemiplegia and aphasia. Eleven patients had transient ischemic attacks. Headache, facial pain, a subjective bruit, oculo-sympathetic palsy and transient monocular blindness were present in various combinations in two-thirds of cases and their presence suggested the correct diagnosis. Examples of suspected dissection of the intracranial internal carotid, middle cerebral, posterior cerebral and extracranial vertebral arteries are also presented. Spontaneous dissection is more common than the literature indicates.
The clinical recognition of dural arteriovenous malformations (AVM) is a challenge to the ophthalmologist. Unilateral dural AVMs produce monocular signs which may simulate orbit disease. A patient with bilateral dural AVMs presenting with bilateral congestive exophthalmos resembling dysthyroid ophthalmopathy is reported. Spontaneous resolution of the ocular manifestations occurred.
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Eight pathologically proven cases of pineal region tumors examined by computed tomography (CT) were found upon reviewing 11,000 consecutive CT studies at the Massachusetts General Hospital. The CT scan findings of the eight cases are described and related to a pathological classification of pineal tumors.
Computed tomographic scans were performed in 34 patients following lumbar introduction of metrizamide. Imaging of the cranial spaces was obtained with horizontal and inclined (25 degrees) as well as coronal planes. Mass lesions within and encroaching upon the cisternal spaces were demonstrated, and the ventricular system was shown with varying degrees of opacification. Coronal and semicoronal views facilitated the localization of parasellar and incisural mass lesions.
Review of computed tomographic (CT) scans of 49 consecutive patients with surgically excised acoustic neuromas revealed positive scans in 80% following contrast enhancement, with 20% false negative scans. All tumors over 2 cm in diameter were shown by optimal scans with contrast enhancement. The positive scans were evaluated to determine the accuracy of the size of the lesions as predicted by the scan. A radiological approach to the evaluation of suspected acoustic neuromas is suggested.
Enhancement of CT attenuation values of the CSF cisterns by the lumbar injection of metrizamide has been shown to be of value in demonstrating the anatomy of the cisterns. Tumors involving the cisterns, such as acoustic neurinomas and pituitary adenomas, are clearly defined. Coronal scanning was superior to horizontal views in many cases.
Cisternography with metrizamide (Amipaque) and hypocycloidal tomography was found to depict cisternal anatomy with detail and precision not obtainable with any other technique. Clinical tolerance is comparable to that of encephalography if suitable precautions are followed. All side effects observed had disappeared 36 hours after injection, and no delayed noxious effects were recorded. This method offers a simple, rapid and precise technique for depicting cisternal anatomy and requires no equipment other than a tilting multidirectional tomographic unit.
CT scanning has proven efficacy for the demonstration of normal and altered anatomy of the soft tissues of the head, providing information not available with any other modality. The introduction of total body CT has enabled us to study the entire spine and its contents. This new modality is extremely useful in diagnosing a variety of abnormalities of the spine, including diastematomyelia. A case is presented and the application of CT scanning to the spine is discussed.
Although a probable initial diagnosis may be suggested by computed cranial tomography, the diagnostic accuracy is often increased by the complementary use of other neuroradiologic studies. The use of CT scanning is conjunction with other more invasive neuroradiological studies results in improved diagnosis and patient management in almost the entire spectrum of neurosurgical diseases-- subarachnoid hemorrhage due to aneurysm, stroke, trauma, normal pressure hydrocephalus, and especially neoplasms.
The diagnostic contribution of contrast enhancement by intravenous injection of meglumine diatrizoate was assessed in 121 patients who received both plain and contrast enhanced cranial CT scans. The use of contrast enhancement was found to provide both an increased sensitivity in detection of lesions and some improvement in pathological differentiation of lesions. The use of contrast enhancement in addition to plain CT scans increases the reliability of CT scans in excluding such conditions as neoplasms, abscesses, and vascular malformations. Because the use of contrast medium is associated with morbidity (and significantly extends the length of the total study), the decision to employ contrast enhancement must be based upon a careful evaluation of the clinical, other radiological, and plain CT findings in the individual patient.
Infusion of intravenous contrast medium with computed cranial tomography must be utilized judiciously. It is indicated to improve the detectability of lesions and to assist in differntial diagnosis.
Two cases of extradural epidermoid cyst and one case of xanthoma are reported in order to describe the computed tomographic and other radiographic findings. Contrast enhancement of the margin was seen in all of the cases. Absorption values almost as low as those found with cerebrospinal fluid were present in the central region of the lesions.
In cases with radiation necrosis of the brain, conventional neuroradiological examinations usually demonstrate only an avascular mass lesion impossible to differentiate from intracerebral tumor or hemorrhage. Computed tomography, performed in addition to angiography in three cases, consistently demonstrated the radiation necrosis as a low density area exhibiting enhancement following infusion of contrast medium. The importance of recognizing radiation necrosis as a differential diagnosis to brain neoplasm is emphasized.
Eighty-five cases of hemangioblastoma of the spinal cord are reviewed, including five new ones. While current views of the incidence, histology, and cytogenesis are presented, the main purpose of this article is to call attention to the identifying clinical and radiological characteristics of these spinal tumors. Median age at onset of symptoms was 30 years. The ratio of men to women was 1.1:1. Presenting symptoms were usually radicular pain or posterior column sensory loss or both. The lesions were most often single (79%), intramedullary (60%), and located in the cervical or thoracic spinal cord. There was associated syringomyelia in 67% of intramedullary cases and meningeal varicosities in 48% of all cases. Lindau disease and hemangioblastomas in other central nervous system locations were present in 33% of cases. The characteristic roentgenographic picture is a densely vascular tumor in association with a larger avascular syrinx and meningeal varicosities. Surgery is the only definitive treatment.
Primary intracranial intradural extraventricular epidermoid tumor may be suggested by the findings on computed tomography (CT), which is also useful during the follow-up period. Epidermoid tumors may exhibit minimal symptoms and have usually spread far beyond their original site by the time they are found. Early detection, delineation, and characterization are possible with CT.