Titanium clips in neurosurgery for elimination of artefacts in computer tomography (ct) a technical note.

To eliminate the occurrence of artefacts produced by clips on the CT images, the use of titranium clips is suggested. Tests in vitro and in vivo indicate that clips manufactured from 0.2 mm thick 99.

Variation with time of the attenuation values of intracranial hematomas.

Fourteen cases of subdural, epidural, and intracerebral hematoma, in which the time of the trauma or bleeding was known, were selected. Attenuation of samples taken at surgery showed good correlation with attenuation values determined by computed tomography (CT). The decrease in the attenuation of the hematoma from the time of trauma or bleeding was studied.

Diagnosis of intrasellar cisternal herniation (empty sella) by computer assisted tomography.

Twenty-six cases of empty sella were studied using computer assisted tomography (CAT). Emphasis was placed on the technical factors controlling the pictures. The diagnosis seems to be feasible in a large number of cases provided movement artifacts are reduced and the angulation, thickness, and level of the cut are carefully chosen.

Picture processing in computed tomography.

Using the EMI scanner system computer, picture processing of various kinds can be performed. Computer programs enabling analysis of regions of interest, subtraction, smoothing, and reconstruction in three dimensions have been designed; they are easy enough to be handled by the regular staff. The potential of the methods is illustrated.

Stereotaxic computed tomography.

A method for stereotaxic computed tomography is described. A head fixation system has been devised enabling the exact transfer of information fromthe diagnostic coordinate system of the scanner to other therapeutic or diagnostic coordinate systems.

Airway closure during mechanical ventilation.

A nitrogen-dilution technique for measurement of airway closing volumes (CV) and functional residual capacity (FRC) not requiring subject cooperation was tested in five healthy, awake, spontaneously breathing subjects and subsequently used in 20 patients during anesthesia with mechanical ventilation. Incomplete exhalation before inhalation of oxygen did not significantly alter CV. Inspiration of a volume of oxygen equal to 75 per cent of vital capacity (VC) did not affect CV, whereas inspiration to 50 percent VC resulted in a 20 per cent decrease in CV.

The limitations of definition of blood vessels with computer intravenous angiography.

Using a polystyrene phantom and various concentrations of iodine contrast material, the discrimination of blood vessels by the EMI scanner was studied. Although a 2 mm tube can be delineated using high concentrations of iodine, smaller tubes are not seen due to noise inherent in the system.

Computer intravenous angiography.

Computer tomography could be useful in demonstrating lesions of intracranial vascular structures. Experimental methods aimed at achieving this are presented and clinical examples using intravenous angiography are given. The factors involved by the demonstration of intracranial vessels are discussed.