The base view in vertebral angiography. An aid in the diagnosis of extraaxial cerebellopontine angle tumors

Though the advent of computed tomography has improved the detection of posterior fossa lesions, there are times when it can not be used to differentiate between an intra- and extraaxial lesion, particularly when the mass is anteriorly located. Base view angiography can be used to make this distinction, accurately localize the lesion, and demonstrate involvement or compression of vital adjoining structures.

Role of computerized tomography in the diagnosis of acoustic neuromas

Computerized tomography has manifest usefulness in the roentgenologic identification of intracranial masses, and acoustic neuromas are no exception. Nonetheless, traditional roentgenographic examinations for the workup of acoustic neuromas should not yet be completely discarded in favor of this new modality. Computerized tomography scanning is an insensitive and unreliable technique for delineating the size and configuration of the internal acoustic canals. With current technology, it will not reliably show neuromas less than 1.5 cm in cross-sectional dimension. Technical artifacts may also contribute to false-negative and though rare to false-positive findings. The false-negative rate will be unacceptably high in the presence of small lesions if this technique is treated as a definitive examination rather than a screening one. Though uncommon, it may also be negative in the presence of relatively large lesions.

Computed tomography in pediatric diagnosis

The use of computed tomography has revolutionized the evaluation of the neurologically ill child. This safe and noninvasive procedure may be done on an outpatient basis, eliminating for many the complications that may occur from invasive neuroradiologic procedures. Computed tomography is of particular value in the assessment of intracranial neoplasms, hydrocephalus, and vascular disease. Further advancements are expected in the technology of computed scanning and in its diagnostic use in the rest of the body.

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.

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.

Neuroradiology of basal anterior fossa (transethmoidal) encephaloceles

Encephaloceles of the basal anterior fossa, though primarily congenital in origin, may be insidious in presentation and remain undetected until adulthood. Conventional plain films and hypocycloidal tomograms show a basal osseous defect with its margins bevelled toward the nasopharynx. Magnification angiography is the diagnostic study of choice and reveals herniation of the anterior inferior frontal artery through the osseous defect. Pneumoencephalography, the classical technique of investigation, was found to be unrewarding in demonstrating the herniated sac or in determining the presence or absence of brain tissue within the sac; however, it is of value in demonstrating a ventricular communication with the encephalocele and evaluating ventricular dilatation.

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.

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.

Radiologic features of benign pleomorphic adenoma of the hard palate

The clinical and radiographic features of two cases of pleomorphic adenoma are discussed. With the use of hypocycloidal tomography, definitive radiographic signs of benignity are demonstrated. They include (1) a radiolucent defect with well-defined cortical margins; (2) beveled margins which describe an intraoral origin of the neoplasm; (3) confinement of the neoplasm within the actual osseous defect, or within the projected circumferential diameter of the defect, if complete erosion has occurred; and (4) lack of periosteal reaction or osseous involvement of the hard palate adjacent to the radiolucent defect.