Biomedical subjects
Publications and source records attributed to E Kazner.
41 patients with brain stem gliomas are presented and analyzed. Optimal therapy as well as outcome depend on the histological identity of the tumours. Histological examination cannot be replaced by CT, angiography and NMR. Therefore stereotactic biopsies are recommended in all cases with brain stem gliomas.
An attempt is made to utilise so-called absorption analyses in cranial CT for further differentiation of the diagnosis of the various types of space-occupying growths. Characteristic distributions are shown for specific "regions of interest" in meningiomas, glioblastomas and cerebral abscesses before and after contrast medium injections. Clear criteria can be formulated for the differentiation of glioblastoma and cerebral abscess using multivariate discriminance analyses.
13 cases of bilateral necrosis of the putamina in children and adults are reported. CT shows similar parenchymal defects, though clinical data reveal different histories, causes and circumstances of the damage. The relationship between CT findings and clinical symptoms is investigated, and the neurological dysfunctions resulting from symmetrical areas of necrosis in each putamen are discussed.
Sixty-five patients with recurrent radicular complaints after operation for lumbar disc herniation underwent CT examination before and after intravenous contrast application (volume: 1.5-2.0 ml/kg body weight; flow rate: 0.35 ml/s). Postsurgical hypertrophic scar tissue showed definite contrast enhancement, whereas disc herniation remained unenhanced. Intravenous contrast application is recommended in patients previously operated upon for disc herniation.
With the help of a personal computer we have subjected 1684 tumours of the central and peripheral nervous systems to a discriminant analysis to test whether the different brain tumours can be classified. By ascribing a coefficient value which belongs to a linear function to the objective criteria for each tumour these can be ordered in groups, and a classification is then possible. This has been termed discriminant analysis. Fifty histological characteristics were the criteria taken into consideration for each tumour. By using Bayes' formula with a correction for binomial distribution we obtained a correct diagnosis in 98% of the cases studied. The differential diagnosis with its percentage of probabilities is given by the computer. The mathematical fundaments are given. The valuability and precision of this method are discussed.
The current paper is a review of our experience of 1200 examinations of the brain, using magnetic resonance tomography (MRT), derived from a mixed neurological and neuro-surgical clinic. MRT has advantages in localisation and tissue characterisation. Localisation is improved by the ability to obtain coronal and sagittal images and by the absence of artifacts due to bone in lesions in the middle and posterior fossa. Some tissues and structures (blood, fat, vessels) produce relatively characteristic signals on MRT, which may be important in clinical diagnosis (eg. chronic subdural haematoma). A significant advantage of MRT is its excellent contrast resolution of soft tissues; this results in better demonstration of normal brain anatomy (eg. corticomedullary contrast), areas of demyelinisation (eg. multiple sclerosis) and certain cerebral tumours (eg. astrocytomas). On the basis of our experience, certain indications are defined, depending on the physical characteristics of the method; these are illustrated by clinical examples.
Nuclear magnetic resonance tomography was performed on 38 patients with intracranial tumours, before and after the administration of contrast, using a 0.35 T Magnetom. The MR examinations included various plain spin-echo sequences (SE 400/35, 800/35, 1600/35, 1600/70, 1600/105, 1600/120) as well as examinations after the iv-administration of gadolinium-DTPA (SE 800/35). On all occasions, the abnormalities were visible without contrast. Differentiation of tumour and its surroundings was possible in 19 out of 38 cases without contrast. Delineation of expansively growing tumours (eg. meningiomas) was possible in twelve out of 14 cases, but in only seven out of 24 cases with infiltrating tumours (eg. glioblastomas). On the other hand, clear differentiation between tumour and adjacent edema and normal brain, respectively, was possible in 35 out of 38 cases after Gadolinium-DTPA.
MR images were obtained in 15 patients with cystic lesions in the posterior fossa and the results compared with computed tomography (CT). The abnormalities imaged included 5 epidermoids, 3 haemangioblastomas, 4 arachnoid cysts, 1 postoperative cyst, and 4 large cisterns. One advantage of MR is the ability to demonstrate lesions in three planes and without artifacts. Liquor-related intensity measurements of cyst contents provided important information, thereby improving diagnostic specificity and patient management. T2-weighted images were found to be more sensitive in characterising cystic lesions of the posterior fossa than were T1-weighted images. Large cisterns, arachnoid and postoperative cysts had an intensity pattern identical or almost identical to cerebral spinal fluid. More proteinaceous cysts, including epidermoids and to a higher degree haemangioblastomas, had clearly higher intensity than cerebral spinal fluid on the T2-weighted images.
Applying Escudero's formula to Bayes' theorem of conditional probabilities, we have developed a mathematical model to diagnose type-specific brain tumours with great accuracy. We have transformed a multidimensional system of n characteristics on computed tomography into a linear system, making this model very easy to use and, thus, accessible to the clinician and radiologist. We tested this model in 177 brain tumours. In 86% of the cases we obtained a type-specific correct diagnosis, achieving better results than those previously reported. Suggestions are given as to how to improve this method further.
The authors compared the clinical courses and the CT courses recorded at the same time in patients with primary or secondary cerebral tumors. 69 patients improved their neurologic state under external radiotherapy, 35 patients remained unchanged, and 8 patients had a deteriorated condition. The changes in computed tomography and the modifications of the clinical state of patients corresponded only in 55% of all cases. The reasons are discussed. Some patients suffered from fatigue and weak concentration about three months after the end of radiotherapy, in some cases even the neurologic state was deteriorated. These manifestations known as "early delayed reaction" were reversible.
We analyzed the incidence, timing and appearance of reversible CT findings in 55 patients undergoing radiation therapy (dose 60 Gy) for brain tumors. Three patients had "early delayed reactions" within three months of irradiation. CT studies showed increased size of the central zone of necrosis with contrast enhancement in the form of rings or garlands. Differentiation between these findings and recurrence of tumor was possible only through follow-up studies.
The case history over five years of a finally completely tetraplegic patient is described, in whose plegic muscles massive occurrence of positive sharp waves and fibrillation potentials could be found together with normal neurographic parameters. The mediosagittal MRT of the brainstem gave evidence of a tumor in the craniocervical region. The patient could be discharged in healthy condition ten weeks after removal of a foramen magnum meningioma. Evidence of so-called denervation activity was no longer present. For the clinical neurologist as well as for the electromyographer it is equally important to know that positive sharp waves and fibrillation potentials can also occur in central lesions.
Explore the source record for details and available documents.
We report on a series of 21 infants and children with tumors of the supratentorial ventricular system, all of whom were assessed by computed tomography and underwent operation using microsurgical techniques. In 7 cases the tumor was found in the 3rd ventricle, whereas the lateral ventricles were involved in the others. Surgical access to the lateral ventricles and the anterior portion of the 3rd ventricle was gained by standard intergyral cortical incision in the precentral or postcentral regions and via the foramen of Monro. The posterior portions of the lateral ventricle of the dominant hemisphere as well as the posterior part of the 3rd ventricle were exposed with minimal risk, using the occipital midsagittal supratentorial route. Following this technique, total removal of the tumors was possible in all cases without substantial postoperative morbidity. After a follow-up period of 6 months to 9 years all patients are in good or excellent neurological condition. Tumor recurrences were not encountered, although a definitive statement cannot be made in some patients with malignant lesions.
21 patients with clinical and CT diagnoses of intracranial tumor were studied by MRI (NMR) prior to and after administration of intravenous Gadolinium-DTPA. Resultant MRI images were compared with corresponding CT sections with respect to lesion detection, contrast enhancement, tumor delineation and visualization of perifocal edema. All intracranial lesions shown on CT were identified on MRI. Contrast enhancement in MRI images was achieved in 19 out of 21 patients, as it was also with CT. In these cases improved differentiation between tumor, perifocal edema and adjacent brain structures were obtained. In most cases sufficient visualization of perifocal edema in MRI required T2 weighted images (SE 1600/70) in addition to spin echo scans routinely performed prior to and after contrast medium (SE 400/30 or 800/30). No side effects were encountered following administration of Gadolinium-DTPA. The good tolerance and the efficacy justifies the use of Gadolinium-DTPA for contrast enhanced MRI imaging.
The efficacy and tolerability of the dihydropyridine calcium antagonist nimodipine (BAY e 9736) in the prophylaxis of ischemic neurological deficits after subarachnoid hemorrhage were investigated in 171 patients in an open, prospective, multicenter study. 68 of the patients had to be excluded from the efficacy assessment as they had failed to satisfy important inclusion criteria. The efficacy assessment was based on 104 patients of Hunt and Hess grades I-III. In 86 patients the ruptured aneurysm was clipped before or during the nimodipine therapy, while 18 patients did not undergo surgery owing to failure to detect an aneurysm, continuous deterioration of the clinical condition, or for other reasons. At the end of the nimodipine treatment 74 of the patients (71%) were completely free from symptoms or had only very slight neurological deficits. There were 10 patients (10%) with moderate and 10 with a severe disablement, 4 patients were apallic, and 6 (6%) died during the nimodipine treatment. In 4 patients (3.8%) cerebral vasospasm was the sole cause of severe neurological deficits or death, while in a further 3 patients (2.7%) vasospasm and other serious complications were responsible for poor outcome. 22 of the 171 patients (12.9%) died during or shortly after nimodipine therapy. Rebleeding occurred during nimodipine therapy in 7 of the 143 preoperatively treated cases (4.9%).
The present study provides an introduction to the clinical diagnosis of intracranial lesions by means of magnetic resonance tomography (MRT). The demonstration of different tissue qualities (bone and bone marrow, cerebral cortex and medulla, ventricular system (CSF), blood, tumour and perifocal oedema) in the MR tomogram is explained. The principles of specific MRT contrast media and their clinical application in brain tumours are discussed in detail.
In an initial clinical trial we examined the tolerance and the influence exercised on signals in nuclear magnetic resonance tomography by gadolinium-DTPA. In an open study, 4 dosages between 0.005 and 0.25 mmol Gd-DTPA/kg body-weight were tested on 5 healthy volunteers each. To ensure renal elimination of Gd-DTPA, NMR images were produced (0.35 T Magnetom) visualising the kidneys and urinary bladder before and more than 60 minutes after application of the contrast medium. The article shows in what manner the image is influenced by the dosage of the contrast medium and also by the time interval elapsing between injection of the contrast medium and production of the NMR tomogram. - Finally, first clinical results of NMR tomography contrast medium application are demonstrated in the case of 5 patients with cerebral tumours.