Joseph P. Lin

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 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.

Primary tumors and other masses of the cerebellum and fourth ventricle: Differential diagnosis by computed tomography

SummarySeventy-three tumors of the cerebellum and fourth ventricle were analyzed by computed tomography to establish criteria for identifying the location and histology of the tumor. Brain stem tumors and metastases were excluded from the study. Tumors within the fourth ventricle are usually central in location, have a lucent halo and show no evidence of a separate, displaced fourth ventricle. Tumors within the cerebellar hemispheres are usually eccentric in location, lack a halo and displace the fourth ventricle. Ependymomas may be distinguished from classical medulloblastomas because they calcify more frequently, have small lucent zones, and extend into the cisterns of the cerebellopontine angles. Hemangioblastomas may be distinguished from cerebellar astrocytomas because they are usually not calcified, are smaller than astrocytomas and often exhibit central necrosis of smaller tumors than astrocytomas. In many cases, cerebellar sarcomas (desmoplastic medulloblastomas) may be distinguished from astrocytomas by their homogeneously increased attenuation homogeneous contrast enhancement and lack of calcification. In this series, all intraventricular lesions with ring blushes after contrast enhancement, and all but one intraventricular lesion with well defined lucencies, were ependymomas. All calcified extraventricular lesions were astrocytomas. No medulloblastoma, ependymoma or cerebellar sarcoma demonstrated homogeneously decreased attenuation and none was a predominantly cystic mass. The criteria presented tend to localize and identify accurately the vast majority of intraventricular and hemispheric masses, in the posterior fossa.

The normal anterior inferior cerebellar artery. Anatomic-radiographic correlation with emphasis on the lateral projection.

Previous descriptions of the course and anatomic relationships of the anterior inferior cerebellar artery (AICA), as visualized in the lateral projection, have not been found by the authors. Dissection and radiography of 32 injected human cerebella show that AICA and its major branches define the position of the pontomedullary sulcus; supra-olivary fossette; 5th-11th cranial nerves; brachium pontis; flocculus; great horizontal fissure; posterolateral fissure; superior semilunar lobule; inferior semilunar lobule; biventral lobule; foramen of Luschka; and the choroid plexus of the lateral recess of the 4th ventricle. With magnification and high-quality subtraction, AICA and its associated structures may be identified in the lateral projection in the large majority of patients.

The Value of Routine Cranial Computed Tomography in Neurologically Intact Patients with Primary Carcinoma of the Lung

The most common cerebral metastatic lesion is from carcinoma of the lung. Preoperative cranial computed tomography (CCT) with contrast enhancement was performed in 55 neurologically intact patients with a diagnosis of bronchogenic carcinoma; 3 patients (5%) demonstrated cerebral metastasis. CCT could spare a significant number of such patients from unnecessary surgery, with a net saving substantially greater than its cost.

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...

The Usefulness of Computed Tomography During and After Radiation Therapy in Patients with Brain Tumors

Two years of experience with 100 patients in the serial study of brain tumors during and after radiation therapy has shown that computed tomography is useful in (a) depiction of regression or growth of primary and metastatic intracranial tumors, (b) recognition of untoward sequelae of radiation therapy, such as necrosis and edema, and (c) appreciation of changes in tumor density and ventricular size. Representation cases are discussed and illustrated.

Radioiodinated Serum Albumin (RISA) Cisternography in the Diagnosis of Incisural Block and Occult Hydrocephalus

Symptomatic occult hydrocephalus with normal cerebrospinal fluid pressure has recently received considerable attention in the neurological literature. Clinically this syndrome may be manifested by progressive dementia, psychomotor retardation, memory impairment, spasticity, and gait disturbance (1, 9–11). Messert and Baker (11) suggested that its cause may be either “idiopathic or nonobstructive” white matter degeneration or obstruction of cerebrospinal fluid pathways by a variety of lesions. Treatment usually consists of shunting cerebrospinal fluid from the ventricular system to the heart or the pleural cavity. Dramatic improvement of symptoms following shunting procedures has been reported, thus adding impetus to the need for accurate diagnosis (1, 10, 11, 13). The diagnosis of occult hydrocephalus is best made by pneumoencephalography. This study deals with the diagnosis of cerebrospinal fluid obstruction at the level of the tentorial incisura (incisural block). The obstruction of the cerebrospinal fl...

Computed tomography in the postoperative care of neurosurgical patients.

SummaryBy its ability to differentiate the densities of various intracranial tissues, computed tomography is an ideal tool to investigate the postoperative course and complications of neurosurgical patients. The most important immediate postoperative complications are intracerebral edema and epidural, subdural or intracerebral hematomas. The extent of surgical resection of neoplasms can also be studied easily by CT. The method of investigation and representative cases are described.