Norman E. Chase

Evaluation of Sellar and Parasellar Masses by Computed Tomography

Computed tomography is the method of choice for initial evaluation of patients with potential suprasellar masses. In our experience, CT has proved completely reliable for detecting or ruling out the presence of a suprasellar mass, the direction and degree of parasellar extension, and the presence of any calcific or cystic component of the lesion. When multiple cut CT has been negative, further diagnostic studies have proved unrewarding. When CT has been positive, additional studies have been required in some cases to rule out aneurysm prior to craniotomy.

Computed tomography in the diagnosis of extra-axial posterior fossa masses

Extra-axial posterior fossa masses can be diagnosed reliably by computed tomography (CT) in most cases. Acoustic and trigeminal neurinomas, meningiomas, cholesteatomas, and other extra-axial masses can usually be distinguished from intra-axial masses by asymmetric widening of the basal subarachnoid spaces, bone destruction, continuity of the tumor mass with the tentorium or bone, and more sharply defined margins. Multiple-cut study of the posterior fossa improved visualization of the fourth ventricle and basal cisterns. Interpretation of cisternal changes in association with changes in the fourth ventricle and abnormal attenuation coefficients permits accurate diagnosis of posterior fossa masses.

Dense Intracranial Epidermoid Tumors

Three extra-axial posterior fossa epidermoid tumors manifested nearly identical CT appearance of large size, sharp margination, apparently homogeneously increased attenuation in the range of 80-120 Hounsfield units, and absence of contrast-agent enhancement. This constellation of findings is distinctly different from that reported previously, and appears to be characteristic for some epidermoid tumors.

Computed tomography of spinal tuberculosis.

The computed tomographic (CT) features of nine documented cases of spinal tuberculosis are analyzed. The mechanisms of vertebral involvement are reviewed. The ability of CT to facilitate the diagnosis as well as to delineate the extent of soft tissue involvement is emphasized. The need for increased alertness to the diagnosis of tuberculosis is stressed.

Value of Cerebral Angiography in the Embolization Treatment of Cerebral Arteriovenous Malformations

Cerebral angiography is an integral part of the embolization treatment of cerebral arteriovenous malformations. Its value is evident in the preoperative evaluation of the case, for proper selection and planning of treatment, in the operative control of the procedure, and in the postoperative and followup assessments.

Stereotactic surgical system controlled by computed tomography.

The three-dimensional data obtained by computed tomographic (CT) scanning offer an advantage in using this imaging technique for stereotactic surgical procedures. This requires interfacing of CT image data with a stereotactic guide. In the performance of functional procedures where the surgical target must be identified from brain landmarks, such as the anterior and posterior commissures, an image reconstruction technique that presents in an image high spatial resolution structural information must be used. The description of a fully hardware- and software-interfaced CT-directed stereotactic surgical system is presented. The logic of operation and examples of images reconstructed with a high spatial resolution algorithm are illustrated. The experimentally determined measurement of an electrode tip localization with this system is within 1 pixel or +/- 0.5 mm in any direction.

Blood Pressure Changes During Retrograde Brachial Angiography

Investigation of the vascular system by angiographic technics requires the rapid injection of varying amounts of foreign material. This produces numerous chemical and physiological changes in the patient (3, 6, 7, 11, 14). Many of these parameters have been studied previously; however, we have been unable to find any serious investigation of intra-arterial pressure changes during the actual performance of angiography in man. The purpose of this study was to investigate the pressure changes that might occur during and shortly after retrograde brachial angiography, as measured in the brachial artery proximal to the injection site, the carotid arteries, and the systemic circulation as represented by the femoral artery. Material and Methods Our technic of retrograde brachial angiography consists of percutaneous puncture of the brachial artery in the mid-forearm with a 15- or 16-gauge Cournand needle and the injection of 30 c.c. of 50 per cent sodium diatrizoate (50 per cent Hypaque, Squibb) with 15 c.c. of sa...

VISUALIZATION OF TENTORIAL BRANCHES OF THE INTERNAL CAROTID ARTERY IN INTRACRANIAL LESIONS OTHER THAN MENINGIOMAS.

The purpose of this report is to demonstrate that the tentorial branches of the internal carotid artery may be visualized in intracranial lesions other than tentorial meningiomas. Bernasconi and Cassinari in 1956 showed a tentorial artery in 5 of 7 patients with tentorial meningiomas and postulated its specificity in the angiographic diagnosis of these tumors. They were uncertain as to the origin of the vessel since common carotid punctures had been performed in all cases, but considered it to be a branch of the external carotid artery. In 1957 Krayenbuhl and Yasargil demonstrated this artery in a patient with a subtentorial arteriovenous malformation, but thought it represented a primitive trigeminal artery. Wickbom and Stattin (1958) observed the tentorial artery in 2 tentorial meningiomas. They were the first to state that the tentorial artery arose from the internal carotid artery, but thought that it did so before the carotid penetration of the outer dura. Frugoni et al. (1960) observed the tentorial...

Carotid stenosis and intracranial emboli.

Middle cerebral branch occlusions were evaluated relative to lesions in the extracranial carotid arteries, showing increased incidence in patients with irregular and ulcerated plaques compared to those with normal or smoothly stenosed arteries. Limitations in the diagnosis of ulcerative plaques and embolic middle cerebral branch occlusion by angiography are pointed out.

CEREBRAL ULTRASONIC TOMOGRAPHY.

Ultrasonic acoustic waves have been used in recent years to delineate the structure of biological tissues. The principles are similar to those of marine sonar equipment for ocean depth determination and the location of submarines (3, 17, 18). In 1950 French and his co-workers (6, 7) attempted to delineate cerebral structures by ultrasound technics. Wild and Reid in 1952 then devised methods for differentiating mass lesions in other parts of the body (17, 18), which required immersion of the body part in a liquid. Modifications of this immersion technic have subsequently been employed by others (4, 10). The pulse echo method to locate the position of the midline structures of the brain in living patients was described by Leksell (14) in 1956, and later by others (2, 5, 8, 12, 15, 16). Kikuchi and Tanaka employing the method first described by French, Wild, and Neil in 1951, went a step further and tried to identify the structures observed with an ultrasonic pulse (13). This attempt was made on the living h...