Irvin I. Kricheff

Computed Tomography and Positron Emission Transaxial Tomography Evaluations of Normal Aging and Alzheimer's Disease

Young normal subjects, old normal subjects, and patients with senile dementia of the Alzheimers type (SDAT) were studied with both computed tomography (CT) and positron emission transaxial tomography (PETT). Increases in ventricular size with both aging and disease were measured. Regional glucose metabolic rate was not affected by age, but was markedly reduced in SDAT patients. These data indicate that in normal aging, structural brain changes may be more salient than biochemical changes. Although both structural and biochemical changes occur in SDAT, the biochemical changes are more marked. The results suggest that PETT is potentially more useful than CT in the in vivo diagnosis of SDAT.

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.

Evaluation of Pediatric Hydrocephalus by Computed Tomography

Computed tomography (CT) is a safe and reliable technique for the study of children with increased head circumference. Hydrocephalic children requiring drainage of cerebrospinal fluid may be shunted on the basis of the CT scan alone and their postsurgical course followed by serial CT scans thereafter. Any additional pneumographic studies required may be performed via the existing shunt tube, eliminating transcerebral catheterization and its attendant complications.

Computed tomography evaluations of brain-behavior relationships in senile d dementia of the Alzheimer's type☆

Neuropathological investigations have demonstrated brain-behavior relationships in senile dementia of the Alzheimers type (SDAT), but CT studies have not produced consistent findings. We hypothesized that these discouraging results were in part due to limitations in the methods of CT scan evaluations, and to non-homogeneity of patient populations. The present study examined 43 out-patients with the presumptive diagnosis of SDAT using 37 cognitive test measures and 3 independent CT evaluation strategies. The CT methods included a new rank ordering procedure and two previously used techniques, physical measurement and 4-point rating. Highly significant (p less than or equal to 0.01) brain-behavior correlations were attained using the ranking and rating procedures for evaluation of ventricular and cortical pathology. It was found that rank ordering has high interrater reliability and is superior to the other methods for the evaluation of the ventricular system. The physical measurement of the third ventricle is the single most powerful linear correlate of cognitive impairment. Measurement of cortical sulci are of no correlational significance. Multiple regression analyses indicated that global assessments are the best cognitive predictors of both ventricular and cortical pathology. Thus the present study has demonstrated brain-behavior relationships in vivo in SDAT.

Angiographically undetected ulceration of the carotid bifurcation as a cause of embolic stroke.

The accuracy of angiographic diagnosis of carotid artery ulceration was evaluated. Of those carotid bifurcations showing ulceration at surgery, 60% were diagnosed as having ulcers at angiography. Half of the remaining ulcers occurred in smooth, benign-appearing plaques and were too small to be seen at angiography. An incorrect angiographic diagnosis of ulceration was made in 17 of 50 carotid arteries; in most cases this was due to the presence of a subintimal hematoma in the wall of the artery.

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.

Computed Tomography of Arachnoid Cysts

The typical CT appearance of intracranial arachnoid cysts may obviate additional neuroradiological procedures. Ventriculography using water-soluble contrast media may differentiate a suprasellar arachnoid cyst from a dilated third ventricle. Twelve cases are presented.

Catheter and material selection for transarterial embolization: technical considerations. II. Materials.

In this second part of the report, the authors discuss the advantages and disadvantages of several embolization agents. These include Gelfoam, silicone spheres, polyvinyl alcohol foam (PVA), isobutyl-2-cyanoacrylate (IBCA), silicone fluid mixtures, and tantalum powder. The techniques employed and conditions under which these materials should be used are discussed.

Transfemoral Catheter Embolization of Cerebral and Posterior Fossa Arteriovenous Malformations

Abstract The transfemoral percutaneous catheterization technique for embolization of intracranial arteriovenous malformations is described, and its advantages over arteriotomy discussed. The use of preoperative and postoperative radionuclide flow studies as well as of angiography is suggested. The first report is given of embolization of the intra-axial blood supply of a posterior fossa arteriovenous malformation.

Brain death: II. Neuropathological correlation with the radioisotopic bolus technique for evaluation of critical deficit of cerebral blood flow

An innocuous intravenous portable radioisotopic test using technetium 99m pertechnetate was employed to demonstrate the deficit of cerebral blood flow associated with brain death. The results are compared to those of bilateral carotid and vertebral angiography in 20 patients. Absence of a bolus tracing from the head in the presence of a control tracing of a bolus from the femoral artery in two successive studies one hour apart reliably correlated with the clinical and electroencephalographic findings signifying cerebal death in comatose, apneic patients. Angiography indicated absence of intracranial circulation in 10 patients. Stasis filling or retrograde emptying of arterial vessels (or both) occurred in 7 patients. There was no evidence of venous filling in any of these 17 patients; all of them had either an absent head bolus or an “intermediate tracing.” Results indicate that either form of tracing represents a critical decrease of cerebral blood flow. Two other patients had evidence of severely impaired abnormal posterior fossa circulation without angiographic evidence of cerebral circulation; both of these patients had an absent head bolus. An additional patient had an unusually small head bolus, and angiography revealed extravasation of radiopaque material but no evidence of intracranial circulation. We conclude that the bolus technique is a helpful adjunct in diagnosing brain death.