[Computerized axial tomography of the skull - diagnostic possibilities and clinical results (author's transl)]

Computerized axial tomography is a new method of tissue examination with x-rays whereby a picture can be produced which is a representation of a slice of the skull. This is done by irradiating the skull from 180 or 225 incremental angles and measuring the absorption at each of these angles. Then with the aid of a computer a tomogram is produced which can be displayed on a screen. These tomograms are representations of a cross-section of the skull composed of 160 X 160 points showing the various intracranial structures with great detail. The present study demonstrates the diagnostic possibilities of the high definition matrix with reference to brain disorders in a large sample of patients for the first time. Some tumours are shown as areas of decreased absorption compared with normal brain tissue. Others, however, have been found to have higher absorption values. With glioblastomas very contrasting pictures are produced with coexistng areas of decreased, increased and similar values to brain tissue. The most important finding is the visualization of brain oedema which appears as a low density area. A grading system of brain oedemas is proposed. The brain oedema associated with tumours has been found to propagate mainly in the white matter producing finger-like shapes. Out of 209 intracranial tumours 203 were recognized in the plain scan, a further five after contrast enhancement. In patients who have suffered from a stroke the differentiation between haemorrhage and infarction is made simple due to the contrasting appearance between the two types of lesion. Location, size and propagation direction of a haematoma as well as rupture of a haemorrhage into the ventricular system can be defined exactly. With brain infarction the hypoxically damaged tissue is well delineated and readily attributable to a given vascular area. In head injuries, for the first time it is possible to differentiate brain contusion with oedema from intracerebral haematoma. Coup and contre-coup are demonstrated. All types of acute intracranial haematomas may be diagnosed easily. With chronic subdural haematomas the new method fails if the contents of the haematoma shows the same absorption values as brain tissue. Late sequelae of head trauma such as contusion defects and necrosis of tissue after oedema can be seen in the tomogram. With infantile hydrocephalus, subdural effusions and malformations of the brain, computerized axial tomography offers a complete diagnosis so that other invasive, neuroradiological investigations may be avoided. Orbital tumors are picked out with great clarity. The high definition matrix allows the demonstration of the optic nerve, the lense and the suspension of the eyeball. Without doubt in the coming years computerized axial tomography will play a dominant role in the diagnosis of brain disorders.