Biomedical subjects
Publications and source records attributed to H Hacker.
Computed tomography (CT) of 22 patients with histologically verified oligodendroglioma showed calcifications in 20 cases and contrast enhancement in 14. All of the enhancing cases proved to have malignant histological features. In 2 of the 14 malignant tumors, definite CT evidence (fluid-fluid level) of a cystic component was present.
Objective digital determination of CSF spaces is discussed, with ventricular and subarachnoid spaces handled separately. This method avoids the difficulty of visual definition of ventricular borders in planimetric measurements. The principle is to count automatically all pixels corresponding to CSF in a given region with a Hounsfield unit and to multiply this number by the pixel size. This will give the total surface area of CSF spaces in square millimeters. The calculation of pixel values for CSF spaces and brain tissue is experimentally formulated taking the intersection of the Gaussian curves for ventricular content and brain tissue. In practice, the determination of CSF spaces is done by first calculating a histogram of the total brain in a given slice defining all CSF spaces. Next a histogram of a region including ventricles with adjoining tissue is calculated and the ventricular size is calculated. By subtraction of the ventricle value from the total CSF space value, the subarachnoid space size is obtained. The advantages of this method will be discussed.
After studying the histograms of 87 supratentorial brain tumors and 4 abscesses before and after contrast medium injection and analyzing the results, we attempt to determine characteristic signs of the various kinds of tumors in order to improve their pathologic definition. The meningiomas, astrocytomas, and abscesses seem to show the most standard signs. The metastases are the most variable kind of tumors.
The diagnostic information obtained from 35 examinations of the skull base by computed tomography (CT) was compared with the findings furnished by conventional or blurring tomography (BT). Computed tomography yielded diagnostically valuable information not only on the soft tissues but also on the bony structures. Compared with BT, CT was superior in 40%, equivalent in 40%, and inferior in 20% of the cases in assessing pathological findings involving the bony structures of the skull base. Obviously, CT's additional capability of accurate display of soft tissue changes represents a fundamental diagnostic advantage.
Computed tomographic examinations of parkinsonian patients revealed a high incidence of cerebral atrophy, in most cases a combination of cortical atrophy and ventricular enlargement. The present study considered the relationship between cerebral atrophy and physical signs indicating or promoting arteriosclerosis such as overweight, electrocardiographic changes, hypertension, calcification of the internal carotid artery and aorta as well as elongation of the aorta. The study is based on 173 treated and untreated parkinsonian patients (89 men, 84 women) aged from 37--84 years (mean 64.6), on whom CT was performed about 5.4 years after the onset of the first symptoms of the illness. The results demonstrate an increase of pathological CT findings as well as of calcification in the carotid siphon with advanced age. No correlation was found between the other items and increasing age. Further analysis of the relationship between cerebral atrophy and signs of arteriosclerosis revealed only a statistically relevant correlation with calcification of the carotid siphon, especially with calcification of the media. Since pathological CT findings and calcification of the internal carotid artery are both related to advanced age, whereas all the other items which may be considered to be indications of arteriosclerosis do not have any clear relationship, it is concluded that the cerebral atrophy in Parkinson's disease is not caused by arteriosclerosis.
In the exact diagnosis of space-occupying processes of the lumbosacral spine myelography with water-soluble contrast media is unsurpassed. Neurotoxicity of the water-soluble contrast media is known and feared in many centres. However, after 2500 exclusively in-patient lumbosacral myelographies and after a prospective study of 100 patients we were able to demonstrate that this investigation is only slightly dangerous.
It is possible to demonstrate extremely fine calcification by computer tomography which cannot be shown by skull radiographs. A value of + 70 CT units was found to be the limit below which calcification visible on the CT could no longer be demonstrated radiographically. The incidence of calcification of the falx and of the choroid plexus is considerably greater on the CT than on radiographs, although no difference was found for calcification of the pineal body. Since it is possible to demonstrate cerebral substance and CSF pathways simultaneously, it is possible to obtain an exact anatomical localisation of any calcification. CT is the method of choice for the demonstration and investigation of intracranial calcification.
In addition to showing the structures of the brain, it is possible with computed tomography to demonstrate the bone of the skull. For this the window width has to be increased, or one has to use additive photographic manipulation (integral photography). The clinical value of views of the skull base is illustrated. The advantages of computed tomography compared with conventional radiographic technique are stressed.
A technique is described which, by exact timing of injection and computed tomography (CT) scans, allows a high contrast medium concentration in blood (14 mg iodine/ml blood) to be reached for a brief period, sufficient for a fast scan of 5 to 10 sec duration. This scan demonstrates the early perfusion of the vascular bed of the various organs. With serial, fast CT scans of the same section with 30 sec intervals for 3 min, a dynamic investigation of contrast medium distribution in vessels, tissue, and excretory pathways may be obtained. Preliminary experiments indicate the promising usefulness of this type of examination for brain, kidney, pancreas, spleen, liver, and small bowel.
Explore the source record for details and available documents.
A consecutive series of 821 lumbar myelograms in patients operated on for prolapsed disks were analysed. 47 or 5-7% had to be listed false-negative in spite of excellent technical quality. To find out, whether anatomical variations or a special functional state of the subarachnoid space could have prevented a correct diagnosis, clinical symptoms and some special radiological parameters were examined and statistically evaluated: 1. Distances between peduncles of L4, L5, S1 2. Width of subarachnoid space in a coronal section of L4, L5, S1 3. Width of subarachnoid space in a sagittal section of L5 4. Distance between the posterior limit of the body of L5 and the anterior limit of the subarachnoid space. Measurement and statistical correlations did not reveal any correlation between false-negative myelograms and any of the anatomical variants measured. We still cannot rule out false-negative myelograms.
Two typical cases of nasoethmoidal encephaloceles with liquorrhoea, which were operated on by neurosurgeons, are demonstrated. In one case, polyposis of the nose had been operated on twice in childhood, due to the ignorance of the cause with the result of a liquorrhoea. The second patient showed recurrent meningitis with nasal liquorrhoea and turricephaly. The tentative diagnosis of a nasoethmoidal enceplaocele which was suspected by x-ray-tomography and radio-isotopetest could be certified by the aid of detail-angiography. The neurosurgical technique of intracranial, intradural resection of the encephalocele and closure of the liquor fistual with an acrylic flap is shown.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.