Dubois Pj

CT-Guided Fine Needle Aspiration Biopsy of Orbital Optic Nerve, Tumors

Biopsies were done for seven patients who had blinding optic nerve tumors or inflammations, using the fine needle aspiration technique guided by the CT scan. Cytologic material was recovered in this manner in all cases, which allowed the rendering of diagnoses. This allowed for therapeutic planning with minimal therapeutic invasion.

Dynamic Computed-Tomography Study of the Brain

The dynamic computed tomography (CT) study of the brain consists of the rapid intravenous injection of 49 ml of radiographic contrast material in 7 sec followed by serial 5 sec CT scans with interscan times of only I see. The data from these scans can be reprocessed to create 12 segmented images in 35 see. When small samples of four to six pixels of cortex are examined by the cursor, sharp rises of 20 to 25 CT units (500 scale) are seen on the time–density curves. Samples of while matter are usually no more than 2 CT units. When larger cursor samples of 220 to 255 pixels including cortex and white matter are examined, the time – density curves represent a combination of these two patterns. Comparison between symmetrical areas in the two hemispheres generally shows parallel curves in controls. The studies provide high resolution cerebral perfusion images. In ischemia secondary to ipsilateral carotid stenosis, there is depression of the up-slope and a depressed and late peak. Infarctions show a flat perfusion curve. Several patterns in brain tumors are illustrated. The study, simple to perform, adds significant perfusion information to the previously static CT examination of the brain.

Distinction Between Obstructive and Atrophic Dilatation of Ventricles in Children

Abstract The computed tomography (CT) scans of 92 Infants and children were reviewed. Thirty-three had proven atrophy, and 44 had proven obstructive hydrocephalus. Twelve CT measurements were made, and the results were subjected to computer analysis. The pathologic patients were divided into three groups by ventricular size index: mild (33–39%), moderate (40–46%), and severe (greater than 46%) enlargement. Obstructive patients showed much greater measurements for the temporal horn diameter and the frontal horn radius. The angle of the frontal horn was narrower in the obstructed group than in the atrophic patients. As expected, there were significantly more sulci visualized in the atrophic group than in the obstructed group. Three of these four parameters were directly related to concentric expansion of the ventricles in the presence of obstructive hydrocephalus. This is contrasted with passive dilatation of the ventricular system with preservation of the normal ventricular configuration in atrophy. The temporal horn diameter, frontal horn radius, the angle of the frontal horn, and the number of sulci all distinguish between obstruction and atrophy with individual probabilities of <0.05. When used together, they assure a high probability of separating obstruction from atrophy. Preliminary data suggest that these findings may have application in adults, but the number of confirmed observations has been too small for statistical analysis.

A preliminary investigation of the role of dynamic computed tomography in renovascular hypertension.

This preliminary report describes the application of dynamic computed tomography (CT) to the study of the kidney. The study is a simple, rapid, noninterventional test that gives time–density perfusion curves for the renal cortices as compared with aortic perfusion. In normal subjects, renal cortical time–density curves almost parallel the aortic time–density curve. In theory, decreases in perfusion in the kidney should show a renal cortical perfusion curve that is flattened and no longer parallel to the aortic curve. An experimental model for renal infarction was developed in the dog. Time–density curves taken from the infarcted area do show a depressed renal perfusion curve, with a lower peak than the curve for the contralateral kidney. Dynamic CT may be useful in screening human subjects for possible renovascular hypertension.

Atypical Findings in Adrenoleukodystrophy

: Computed tomography (CT) in a child with typical clinical and biochemical features of adrenoleukodystrophy (ALD) revealed striking pathologic enhancement in the centra semiovalia, posterior corpus callosum, and corticospinal tracts within the internal capsules, cerebral peduncles, and basis pontis. Central calcifications were detected within otherwise typical symmetrical low attenuation lesions in the periatrial white matter. These findings further expand the spectrum of CT abnormalities in ALD and may represent a link between the recently described Type 1 and Type 11 CT patterns.

Rapid Development of Cerebral Atrophy Due to Perinatal Herpes-Simplex Encephalitis

: A case of neonatal herpes simplex virus (HSV) encephalitis is reported in which diffuse cerebral hemorrhagic lesions were seen in the neonatal period. Severe progressive cortical atrophy with parenchymal calcification developed over the subsequent 9 months, resulting in a striking computed tomography (CT) appearance. The range of CT findings in neonatal HSV encephalitis is reviewed, and differential diagnostic considerations in the present case are discussed.

Assessment of Craniocervical Junction and Atlantoaxial Relation Using Metrizamide-Enhanced CT in Flexion and Extension

Metrizamide-enhanced computed tomographic (CT) myelography has made it easier to define the relation of the spinal cord to the vertebral canal. A flexion-extension metrizamide-enhanced CT technique has been developed to study the craniocervical junction that refines evaluation of the relation between the spinal cord and the foramen magnum, atlas, and axis. This technique was used to study 15 adults who had had a structurally normal examination of the upper cervical cord and foramen magnum. The average movement of the upper cervical cord was shown to be 1 mm. The advantages of the flexion-extension metrizamide-enhanced CT examination were evident in 10 other patients who had a variety of craniocervical junction pathologies.

Error sensitivity of computerized tomography guided stereotaxis.

Abstract The accuracy of target localization by computerized-tomography (CT)-guided stereotaxis is analyzed with the aid of computer simulation experiments. Factors such as size and shape of the localizing structure are considered. The results support the conclusion that localization errors in CT stereotaxis can be held below 1 mm.