Computed tomography in the postoperative care of neurosurgical patients

By 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.

Chordoma: radiologic evaluation of 20 cases

Experience with 20 cases of chordoma is summarized. Three of four intracranial tumors presented as sellar tumors. The clivus remained intact for 2, 3 1/2, and 4 years, respectively, in three patients despite extensive destructive lesions of the sellar region. Our data and those of others indicate that approximately half the patients with chordomas have erosion of the clivus at the time of initial medical evaluation. The other half mainly have sellar destructive lesions with or without associated clival erosion. Calcification occurs in 50%-70% of intracranial chordomas. A nasopharyngeal mass is present in one-third. Vertebral chordomas often involve two or more vertebrae, producing destructive lesions which often have a sclerotic rim. The intervertebral discs are commonly affected. A paraspinal soft tissue mass, half the time containing calcification, is often present. Sacral lesions are characterized by a midline destructive lesion, occasionally associated with expansion, with or without osteosclerosis. A firm, fixed, extrarectal, presacral mass which may contain calcification or fragments of bone is almost always present.

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.

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.

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.

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.

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.

The anterior inferior cerebellar artery in mass lesions. Preliminary findings with emphasis on the lateral projection

Analysis of abnormalities of the configuration of the anterior inferior cerebellar artery in lateral projection facilitates diagnosis of posterior fossa masses. Cerebellopontomedullary angle lesions frequently cause arcuate posterior-inferior displacements of the rostrolateral artery or reversal of curvature of the ascending segment of the meatal loop. Vermian, hemispheric, intra-fourth ventricular, and suitably situated extra-axial masses alter the plane of the lateral loop of the caudomedial artery. Tonsillar herniation may be detected in patients with hypoplastic or absent posterior inferior cerebellar arteries by analyzing the relationship of the biventral segment of the descending or caudomedial artery to the foramen magnum.

Role of computerized axial tomography in diagnosis and treatment of common neurosurgical problems of infancy and childhood

Computerized axial tomography (CAT) is a new, highly accurate technique for studying the skull and intracranial contents. It is rapid enough to be utilized in acute emergencies and safe enough to be utilized for routine serial followups and evaluation of outpatients with equivocal findings. Because CAT can delineate the ventricular system without need for contrast agent, can distinguish clearly between hematoma and edema and can differentiate cystic from solid tumors, it finds wide application in the evaluation of neurological disease.

The osseous and angiographic features of vertebral chordomas

Eight cases of vertebral chordoma, exclusive of the sacrococcygeus, are presented. The conventional radiographic signs in descending order of importance in differential diagnosis are: destruction of multiple adjacent vertebral bodies; a paravertebral or precervical soft tissue mass; osteosclerosis, seen mainly at the periphery of the destructive lesion; and involvement of the intervening intervertebral disc space. All eight patients had a demonstrable intraspinal extension of chordoma on myelography. Four patients had complete blocks, two epidural in configuration, and two intradural in appearance - indicative of dural invasion by the neoplasm. Four patients had angiographic evaluation. Two demonstrated angiographic features usually associated with soft tissue malignant tumors. Angiography in all four cases was helpful in determining the full extent of the lesion, more so than either conventional radiography or myelography.

Videodensitometry of cerebrospinal fluid pulsations

Roentgen videodensitometry (RVD) during myelography is described in 13 patients with a variety of intraspinal lesions. Abnormalities in the RVD tracing are discussed and correlated with the type of spinal canal obstruction. Intramedullary, intradural and extradural processes may be differentiated by RVD.

Myelographic cervical nerve root deformities

Myelograms of nerve roots and adjacent subarachnoid space were reviewed to characterize 231 cervical root deformities from both symptomatic and asymptomatic patients. Good correlation between specific features of root deformities and clinical significance could not be demonstrated. Some features were slightly suggestive of clinical significance but occurred in a sufficient number of asymptomatic patients to make them unreliable. The most accurate determinants of root deformity significance are clincal and electromyographic findings.

Effects of temperature on diphosphopyridine nucleotide-linked isocitrate dehydrogenase from bovine heart. Aspects of the kinetics, stability, and quarternary structure of the enzyme

A temperature-dependent conformational change of the active DPN-linked isocitrate dehydrogenase was observed. When initial reaction kinetic data were examined between 35 and 5 degrees, the Hill number (n) varied from 2 at higher to n approaching unity at lower temperatures, with an inflection point at 17 degrees. The presence of manganous isocitrate in the incubation media shifted the transition temperature for enzyme inactivation by 5,5'-dithiobis(2-nitrobenzoate) from 8-16 degrees. These temperature-dependent transitions were paralleled by progressive changes in sedimentation velocities from s20, w of 10.4 at 25 degrees to 7.3 at 10 degrees as measured by active band centrifugation. The linear Arrhenius plot for apparent V max and the constancy of S0.5 for the substrate manganous isocitrate between 35 and 5 degrees suggest that this temperature-dependent conformational change may not be solely related to manganous isocitrate. Further indications of equilibria between different species of enzyme in solution and effects of substrates and cofactors on conformation came from studies of specific activity of enzyme diluted into buffers at 3 and 25 degrees. Dilution to concentrations between 10 and 25 mum enzyme resulted in relatively rapid protein concentration-dependent inactivation which could be prevented and fully reversed by manganous isocitrate. No further substantial inactivation was found subsequent to this phase at 25 degrees. Lowering the temperature of the dilution buffer to 3 degrees favored formation of enzyme species exhibiting a further time and pH-dependent loss of activity which became independent of protein concentration below 7 mum enzyme. The rate of cold inactivation was reduced by raising the ionic strength of the buffer and its progress could be arrested by manganous isocitrate; however, the substrate did not restore the original activity.

Carotid artery occlusion following ingestion of LSD

A 20-year-old white woman developed a left hemiplegia following the ingestion of LSD. Initial angiography revealed marked constriction of the internal carotid artery at the level of the siphon which, in a few days, was converted to occlusion of the carotid artery at that level. It is suggested that LSD, an amine derivative of the ergot alkaloids, was responsible for the initial vasoconstriction and subsequent occlusion.

Relation of preoperative angiographic characteristics of the posterior communicating artery to the results of common carotid ligation

✓ Twenty patients with posterior communicating artery aneurysms were treated with common carotid ligation. Postligation visualization was accomplished in 16 cases by ipsilateral brachial angiography. Two other aneurysms were visualized by contralateral brachial and contralaterial carotid angiography. The size of the aneurysm was measured before and after ligation. The relationship of postoperative reduction in size to preoperative angiographic characteristics was studied. Reduction in the size of the aneurysm occurred most often when preoperative angiography showed that the sac was long and its neck narrow, and when there was stasis of contrast material in the aneurysm.

Intracranial aneurysm on a persistent primitive trigeminal artery. Case report

✓ The angiographic demonstration of a rare case of persistent trigeminal artery aneurysm is reported. The incidence of persistent trigeminal artery in the authors' series is 0.6%. Approximately 14% of patients with a persistent trigeminal artery also have an intracranial aneurysm. The embryology involved and related cases are reviewed.