Paul M. Duchesneau

Comparison of cisternal and lumbar CSF examination in leptomeningeal metastasis

We compared cisternal and lumbar CSF examination in 14 patients suspected of having leptomeningeal metastasis from cancer. Malignant cells were present in 12 patients—in both cisternal and lumbar CSF in nine patients and only in cisternal CSF in three. Cisternal CSF cytologie examination should be considered in patients suspected of having leptomeningeal metastasis if lumbar CSF is nondiagnostic.

Computed Tomography in the Detection of Juxtasellar Lesions

One thousand consecutive computed tomograms were reviewed to determine the accuracy of the procedure in the detection of juxtasellar lesions. The detection rate was compared to those of plain skull films, radionuclide studies, angiography, and pneumoencephalography. Computed tomography was slightly superior to angiography and was surpassed only by pneumoencephalography, both of which are invasive procedures which carry a definite risk. The data indicate that computed tomography is the screening method of choice in the detection of juxtasellar masses.

Basilar Artery Ectasia Demonstrated by Computed Tomography

Basilar artery eclasia was demonstrated by computed tomography (CT) in 4 cases. The course and diameter of the basilar artery as seen by CT closely approximated those aspects of the artery visualized by angiography. The clinical manifestations of basilar ectasia correlated with what brain stem structures were impinged upon by the ectatic artery.

Cervical myelopathy: a comparison of magnetic resonance and myelography

Fifty-seven patients with a strong clinical suspicion of cervical myelopathy were studied with body coil magnetic resonance (MR) and conventional myelography or CT myelography. Eight patients were believed to have normal studies with both modalities. There were six patients with syringomyelia; four with an intramedullary tumor; one with an arteriovenous malformation; 19 with cervical spondylosis at multiple levels; eight with cervical spondylosis at a single level; four with extensive rheumatoid arthritis; four with extradural neoplasm; two with trauma; and one patient with an epidural abscess. In this study, body coil MR was the superior examination for the evaluation of an intramedullary process. It was as diagnostic as myelography in one case of an extramedullary intradural lesion. In patients with extradural disease, body coil MR was the superior study in 45%, equivalent to myelography in 37%, and, although still diagnostic, inferior to myelography in 17%. In 8% of the cases, body coil MR was at best equivocal, whereas myelography was diagnostic. It appears that in technically adequate studies, MR is at least equivalent to myelography in its ability to delineate disease. A superior MR study provides a better appraisal of the size and character of the spinal cord as well as the degree of both anterior and posterior defects on the subarachnoid space and neural structures. In addition, MR is as good as conventional myelography for the identification of extrinsic cervical cord lesions producing cervical myelopathy. Finally, an additional small group of 30 patients were studied with a prototype surface coil to determine its advantages relative to body coil imaging. Each patient had correlative myelography. As with body coil MR, imaging with the surface coil was believed to be more informative than conventional myelography in four patients with intramedullary lesions. The remaining 26 patients suffered from cervical spondylosis. Surface coil MR was believed to be more informative than myelography in six cases (23%), equivalent to myelography in 19 (73%), and less diagnostic than myelography in one (4%). The improved spatial resolution with the use of the surface coil was believed to increase the accuracy of MR.

Interval Computed Tomography in Multiple Sclerosis

Computed tomography demonstrated areas of abnormal attenuation in the white matter in 14 patients with multiple sclerosis (MS). Nine were studied two or more times. Acute MS lesions exhibit decreased or normal attenuation without contrast enhancement and increased attenuation with it. On later scans these lesions show decreased attenuation with or without contrast material. Some lesions remain decreased in attenuation and some become normal both with and without contrast material.

Computed Tomography in Diastematomyelia

The diagnosis of diastematomyelia was confirmed in 2 patients by computed tomography (CT). Abnormalities of the vertebral bodies, pedicles, lamina, and spinous processes were defined and the diastematomyelic spurs were visualized.

White and Gray Matter of the Brain Differentiated by Computed Tomography

The white and gray matter of the brain can be clearly differentiated by computed tomography (CT). The differentiation is enhanced by the administration of contrast material. Without contrast material, the mean attenuation number of the white matter was 29 units, of the gray matter, 35 units. The effective low contrast resolving power of CT scanners can be clinically evaluated by comparing their ability to differentiate the white and gray matter of the brain.

Nuclear Magnetic Resonance of the Spine: Clinical Potential and Limitation

&NA; Magnetic resonance can visualize the vertebral bodies, discs, neural structures, cerebrospinal fluid (CSF), neural foramina, and extradural structures in the sagittal, axial, and coronal planes. The normal nucleus pulposus can be differentiated from the anulus and changes associated with degeneration. Infection, trauma, and neoplastic conditions can be identified. The signal intensity of the CSF relative to extradural and neural structures can be increased to provide evaluation of the size and configuration of the contents of the thecal sac without the use of an intrathecal contrast medium. Impingement by disc, tumors, fracture segments, and expansile masses can then be accurately evaluted, It is the most accurate modality for the evaluation of the foramen magnum, Chiari malformation, syringomyelia, infection, and degeneration of intervertebral discs. It can identify paravertebral soft tissue and bony changes when plain films and computed tomographic (CT) studies are negative or equivocal. Not only can lesions be localized, but significant information regarding the nature of the process can be obtained. Using variations of the spin‐echo technique with appropriate T1 and T2‐weighted images, magnetic resonance can produce tissue contrast distinctions not possible with CT scans or conventional angiography. (Neurosurgery 15:583‐592, 1984)

Diagnosis of Juvenile Angiofibroma by Computed Tomography

Computed tomography (CT) accurately localized juvenile angiofibromata in 3 patients. The expanded pterygopalatine fossa and canal were visualized by CT in all three cases. Because of the hemorrhagic tendency of these tumors, a noninvasive modality such as CT is especially valuable in planning therapy.

Magnetic resonance of intracranial epidermoids

The magnetic resonance images of seven patients with biopsy-proven epidermoids were evaluated. The epidermoids were hypointense on T1-weighted images. Intermediate density images revealed the tumors to be heterogeneous in signal intensity consisting of areas of hypo- and isointensity. Signal intensity on T2-weighted images was hyperintense and inhomogeneous in all but one case. CT performed in five patients demonstrated the tumors to be well-defined hypodense lesions without contrast enhancement.