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K Kitz

Publications and source records attributed to K Kitz.

At least 37 records · Page 2Linked to original sources
PubMed1998

Radio-opaque markers for stereotactic imaging of uveal melanoma.

In in vitro and in vivo studies, episclerally sutured radio-opaque markers were evaluated as localizers for better determination of the clinical tumour volume prior to stereotactic radio-therapy of uveal melanoma. Four different types of markers were studied in vitro: tantalum marker, 2.5 mm in diameter; ring-shaped markers custom-designed in polymethyl methacrylate (PMMA), 2.6 mm and 3.0 mm in diameter; and barium-impregnated silicone rubber spheres, 2 mm in diameter. In vivo PMMA markers 3.0 mm in diameter and barium-impregnated silicone rubber spheres 2 mm in diameter were used. The best results were obtained with the barium-impregnated silicone rubber spheres both in vitro and in vivo. For the CT-delineation of selected uveal melanomas with either a flat discoid shape or flat tumour extensions or when adjacent serous retinal detachment is present, small episclerally sutured barium-impregnated silicone rubber spheres are useful as localizers for determining the clinical tumour volume.

Humans↗
PubMed1996

TLD array for precise dose measurements in stereotactic radiation techniques.

We developed a new TLD array for precise dose measurement and verification of the spatial dose distribution in small radiation targets. It consists of a hemicylindrical, tissue-equivalent rod made of polystyrene with 17 parallel moulds for an exact positioning of each TLD. The spatial resolution of the TLD array was evaluated using the Leskell spherical phantom. Dose planning was performed with KULA 4.4 under stereotactic conditions on axial CT images. In the Leksell gamma unit the TLD array was irradiated with a maximal dose of 10 Gy with an unplugged 14 mm collimator. The doses delivered to the TLDs were rechecked by diode detector and film dosimetry and compared to the computer-generated dose profile. We found excellent agreement of our measured values, even at the critical penumbra decline. For the 14 mm and 18 mm collimator and for the 11 mm collimator combination we compared the measured and calculated data at full width at half maximum. This TLD array may be useful for phantom or tissue model studies on the spatial dose distribution in confined radiation targets as used in stereotactic radiotherapy.

Humans↗
PubMed1996

Acoustic neurinomas with macrocysts treated with Gamma Knife radiosurgery.

Six cases of acoustic neurinomas with macrocystic components are presented. In three cases the cystic portion was within the tumor, while in the other three, the cyst was peritumoral, in the form of a cul-de-sac within the arachnoid, in other words it was not a true tumor cyst. The six tumors are from a series of 74 acoustic neurinomas treated by radiosurgery with a minimum follow-up of 18 months. In all cases, enlargement of the associated cyst was observed as early as 4 months after radiosurgery. Clinical signs and symptoms such as facial weakness, trigeminal symptoms, vertigo and dizziness and coordination disorders developed between 4 and 8 months. In three cases (two intramural cysts and one combined peri- and intramural cyst), subacute microsurgery was performed to treat the progression of neurological symptoms. One case had spontaneous rupture of an intramural cyst, one case of a peritumoral cyst, after progression showed a slow spontaneous size decrease after 2 years, and one case is still under observation. In the reported series, the dose at the tumor margin ranged between 11 and 17 Gy (mean 13.8 +/- 2.5 [SD] Gy) and the maximal dose between 24 and 40 Gy (mean 30.6 +/- 6.2 Gy). In view of the findings in this study, one should perhaps be cautious in advising radiosurgery for this subgroup of acoustic tumors.

Aged↗
PubMed1995

Neuroanatomical details under endoscopical view--relevant for radiosurgery?

Both, neuroendoscopy and radiosurgery, are upcoming techniques in neurosurgery and become nowadays more and more important. In planning radiosurgical interventions it is very important to have both, the information about the morphology of the pathology itself, and also a clear understanding from the surrounding structures. Neuroendoscopic techniques gives the possibility to demonstrate well known structures without prior dissection. This paper focuses on these anatomical informations which might be relevant in planning further radiosurgical interventions especially in cases of the vascularization of the cranial nerves and the arachnoid membranes, these structures appears much more complex than described in "common" neuroanatomical textbooks. Endoscopic techniques also better demonstrate the real in vivo relationships and gives so a better understanding for interpreting "planning" MRI and CT scans. We therefore consider that neuroanatomical studies under a neuroendoscopical view are very important and could be very helpful in planning radiosurgical intervensitons.

Arachnoid↗
PubMed1995

Radiosurgery in the treatment of cerebral AVMs.

Radiosurgery of AVM's is gaining in popularity and is advocated by many for the treatment of lesions less than 3 cm in diameter. During a 17 month period 33 patients with cerebral AVM's were treated with radiosurgery. All regions of the brain were represented in the series including brain stem. A mean follow-up of 10.8 months revealed a 6% rebleed rate and a 9% total complication rate. Multimodality therapy including embolization and surgery is recommended for the treatment of AVM's and radiosurgery is seen as an important adjunctive treatment option.

Adolescent↗
PubMed1995

Microsurgery versus radiosurgery in the treatment of small acoustic neurinomas.

Microsurgical preservation of the facial nerve during removal of acoustic neurinomas can hardly be compared with microsurgery of the eighth cranial nerve. Many more anatomical and pathogenetic factors are involved that need careful consideration. In small neurinomas, of grades I and II, total extirpation of the tumour with preservation of both the facial nerve and segments of the vestibulocochlear nerve not directly involved by the tumour has become a safe and practical technique. In small acoustic neurinomas immediate facial nerve function could be preserved in 88% and "useful hearing" could be preserved in 78%. A number of different types of tumour-cranial nerve relationships could be established in small acoustic neurinomas, showing also the effects of adjusted surgical techniques on the preservation of hearing. Optimal selective separation of cranial nerves from the tumour is only possible through open surgical intervention, while radiosurgery requires the irradiation of the entire tumour/nerve complex.

Adult↗
PubMed1995

The need for adjunctive focused radiation therapy in pituitary adenomas.

In pituitary adenomas radiation therapy regardless of the technique should be limited to surgical failures. The delayed onset of beneficial effects and the high rate of pituitary insufficiency have to be weighed against the good surgical and/or medical results in the treatment of these tumours. Unfortunately surgical outcome is almost invariably correlated with invasive growth. Invasiveness is statistically significantly correlated with tumour size, as well as with high proliferation rates, which can be measured by immunohistological methods such as mAB KI-67. Owing to the good results of medical treatment, radiation therapy is usually unnecessary in prolactinomas. Patients with persistent hypersecretion of growth hormone after unsuccessful surgery may represent the ideal candidates for radiation therapy, whereas patients with persistent Cushing's disease need cure for hypercortisolism without delay. In patients with residual tumour due to non functioning adenomas, radiation therapy should only be given if the proliferation rate is high.

Adenoma↗
PubMed1995

Intra-operative marking of neuroanatomical details--helpful for radiosurgery?

This report is a list of simple but effective techniques for marking important structures intra-operatively. During the last 2 years in 52 patients intra-operative marking techniques have been used. In 37 cases a small piece of fat has been taken. In 10 patients it was done by a radiopaque Barium impregnated silicon sphere and in 5 patients with a piece of a monofilament suture. Postoperative checks were done by conventional X-ray, computer tomography and Magnetic Resonance Imaging. The indication in all cases was to offer landmarks helpful for planning postoperative radiosurgery. In case of fat and radiopaque Barium impregnated silicone spheres the markings were always well defined and clear in contrast. In those cases where a piece of monofilament suture was used it was impossible to get clear postoperative information. In general there were no intra- or post-operative complications. All markers were well tolerated and no side effects have been observed so far. The advantages and disadvantages of each of these possibilities are described and discussed.

Adenoma↗
PubMed1995

Suction fixation system for stereotactic radiosurgery of intraocular malignancies.

We designed a suction fixation system for the radiosurgical treatment of intraocular malignancies with the Leksell gamma unit (gamma knife). OUr device consists of a circular suction chamber and an adjustable unit to be fixed to the Leksell stereotactic head frame. All components are made of plastic materials in order to avoid artifacts in CT or MRT imaging. A permanent suction of 600 to 800 millibars is provided by a standard vacuum pump, powered by a portable battery. Suction times up to 40 minutes were well tolerated in all cases. In the gamma knife of the Neurosurgical Department at the University of Vienna, we successfully used this device. Up to January 1994 we have performed 19 radiosurgical treatments in 9 patients with large or extra-large uveal melanomas and in one patient suffering from a choroidal metastasis.

Aged↗
PubMed1995

Experience with a suction fixation system for stereotactic radiosurgery of intraocular malignancies.

We designed a suction fixation system for the radiosurgical treatment of intraocular malignancies with the Leksell Gamma Knife. Our device consists of a circular suction chamber and an adjustable unit which is fixed to the Leksell stereotactic head frame. All components are made of plastic in order to avoid artifacts in CT or MRI. A permanent suction of 600-800 mbar is provided by a standard vacuum pump, powered by a portable battery. In the Gamma Knife Unit of the Neurosurgical Department at the University of Vienna, we successfully used this device. Up to April 1994 we successfully performed 25 radiosurgical treatments in 12 patients with large or extra-large uveal melanomas and in 1 patient suffering from a choroidal metastasis.

Aged↗
PubMed1995

Detection of tumor necrosis factor-alpha protein and messenger RNA in human glial brain tumors: comparison of immunohistochemistry with in situ hybridization using molecular probes.

Tumor necrosis factor-alpha (TNF alpha) protein and messenger (m)RNA distribution was studied in biopsy samples of glial brain tumors, using immunohistochemistry and in situ hybridization with molecular probes, to investigate the role of this cytokine in tumor proliferation and immunological host defense. Focal expression of TNF alpha was detected in four of four glioblastomas, one of two anaplastic astrocytomas, and four of five low-grade astrocytomas, regardless of their subtype or grade of malignancy, but in none of the normal peritumoral brain tissues used as controls. The TNF alpha protein and mRNA were present in reactive astrocytes and protoplasmic tumor cells, confined to areas of leukocyte or T-lymphocyte infiltrating, and less pronounced in tumor cells at the edge of necrosis. Additionally, TNF alpha reactivity was found in infiltrating macrophages and perivascular microglia. Immunohistochemistry and in situ hybridization for TNF alpha showed comparable reaction patterns and numbers of TNF alpha-positive cells, even though the sensitivity of in situ hybridization was significantly higher. Quantitative evaluation of TNF alpha protein, TNF alpha mRNA, and leukocyte infiltration revealed a significant positive correlation between the TNF alpha-positive reactive astrocytes and the number of lymphocytes present in corresponding areas. Together, these data lead to the conclusion that TNF alpha in reactive astrocytes and monocytic cells within tumor areas of high leukocyte infiltration and in tumor cells at the border of necrosis may represent one defense pathway of the immune system against tumor proliferation.

Adolescent↗
PubMed1994

Results of 200 intracranial stereotactic biopsies.

200 stereotactic biopsies were evaluated. The validity of the intraoperative histopathological results were compared with the final diagnosis using conventional embedding and staining techniques. Further comparison between the histology of the biopsy and the post mortem or open operative findings were possible in 41 cases. Discrepancy was found in one case regarding the tumor detection, and in three cases regarding the tumor grading. The mortality in our patients was 1% and the morbidity 3%. Stereotactical biopsy had a low risk even in deep brain regions such as basal ganglia, mesencephalon, and pons. At the same time the high histologic validity makes the CT-guided stereotactical biopsy recommendable in all lesions not operated by an open resection before any conservative or palliative therapy is started.

Adolescent↗
PubMed1994

Suction attachment for stereotactic radiosurgery of intraocular malignancies.

We designed a suction attachment for the radiosurgical treatment of intraocular malignancies with the Leksell gamma unit (Gamma Knife). Our device consists of a circular suction chamber and an adjustable unit to be fixed to the Leksell stereotactic head frame. All components are made of plastic materials in order to avoid artifacts in CT or MRT imaging. A permanent suction of 600-800 mbar is provided by a standard vacuum pump, powered by a portable battery. Suction times up to 40 min were well tolerated in all cases. We successfully used this device, performing 17 radiosurgical treatments in 8 patients with large or extra-large uveal melanomas and one patient suffering from a choroidal metastasis.

Aged↗
PubMed1993

Immunostaining for proliferating cell nuclear antigen: its role in determination of proliferation in routinely processed human brain tumor specimens.

Alcohol- and formalin-fixed, paraffin-embedded samples of 71 brain tumors (35 gliomas, 22 metastatic carcinomas, 8 meningiomas and 6 other tumors) were investigated by immunocytochemistry with three different monoclonal antibodies against proliferating cell nuclear antigen (PCNA)/cyclin (19A2; 19F4; PC10). PC10 was found to work best; it is applicable to both alcohol- and formalin-fixed tumor samples. PCNA labeling indices (LIs) were compared in the same tumors with LIs obtained by Ki-67 immunostaining of frozen sections and by in vitro incubation with bromodeoxyuridine (BrdUrd); in the latter preparations, BrdUrd LIs could be compared with PCNA LIs in the very same areas of serial sections. In gliomas, PCNA LIs were 0.7-80.2% (mean 31.7%), in metastases 0-76.0% (mean 47.8%), and in meningiomas 0-53.0% (mean 19.3%). In general, PCNA LIs were highly significantly correlated with Ki-67 LIs (P = 0.0002) and BrdUrd LIs (P = 0.0001). However, when tumor subgroups are considered, only gliomas show a significant correlation with Ki-67 and BrdUrd LIs. Despite this statistical correlation, PCNA expression was out of proportion to proliferation indices as determined by both other methods in almost one third of all brain tumors. Immunocytochemistry for PCNA produces a broad spectrum of staining intensity of labeled nuclei, whose number is dependent upon the sensitivity of the immunocytochemical technique used. Thus, inter-observer and inter-laboratory variabilities in PCNA LI determination may occur. Overlapping of PCNA LIs between tumor subgroups of varying malignancy further limits the informational value for the individual case.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Pituitary adenomas with invasion of the cavernous sinus space: a magnetic resonance imaging classification compared with surgical findings.

We present 25 pituitary adenomas that were confirmed surgically to have invaded the cavernous sinus space. The surgical results are compared with the preoperative magnetic resonance imaging findings. For comparable radiological criteria, we classified parasellar growth into five grades. This proposed classification is based on coronal sections of unenhanced and gadolinium diethylene-triamine-pentaacetic acid enhanced magnetic resonance imaging scans, with the readily detectable internal carotid artery serving as the radiological landmark. The anatomical, radiological, and surgical conditions of each grade are considered. Grades 0, 1, 2, and 3 are distinguished from each other by a medial tangent, the intercarotid line--through the cross-sectional centers--and a lateral tangent on the intra- and supracavernous internal carotid arteries. Grade 0 represents the normal condition, and Grade 4 corresponds to the total encasement of the intracavernous carotid artery. According to this classification, surgically proven invasion of the cavernous sinus space was present in all Grade 4 and Grade 3 cases and in all but one of the Grade 2 cases; no invasion was present in Grade 0 and Grade 1 cases. Therefore, the critical area where invasion of the cavernous sinus space becomes very likely and can be proven surgically is located between the intercarotid line and the lateral tangent, which is represented by our Grade 2. We also measured tumor growth rates, using the monoclonal antibody KI-67, which shows a statistically higher proliferation rate (P < 0.001) in adenomas with surgically observed invasion into the cavernous sinus space, as compared with noninvasive adenomas.

Adenoma↗
PubMed1992

Expression of leucocyte adhesion molecules at the human blood-brain barrier (BBB).

The expression of leucocyte adhesion molecules was studied on cerebral endothelia by immunocytochemistry. In peritumoral "normal" brain tissue we found low endothelial expression of ICAM1, LFA3, CD44, and CD9, whereas VLA1 was present on vessels in high incidence and density. LFA1, CD2, and CR3 were found on intraluminal and parenchymal leucocytes, but were absent on brain vessels. In brain tumors and inflammatory brain lesions, we observed an up-regulation of endothelial ICAM1 and LFA3 expression, whereas other adhesion molecules on endothelial cells remained unchanged. Within the brain parenchyma, ICAM1 and LFA3 were found on astrocytes and tumor cells; on the contrary, LFA1 was expressed on microglial cells similar to CR3. CD44 and CD9 showed a diffuse neuropil expression in normal and tumoral tissue, whereas VLA1 was not expressed on any parenchymal cells. Our data show that multiple different adhesion molecules are present on blood-brain barrier endothelium (BBB) under normal conditions and some adhesion molecules are up-regulated in brain tumors and under inflammatory conditions. The presence of adhesion molecules in the vessel walls as well as on parenchymal cells like astrocytes and microglia may guide inflammatory cells into and through the brain in the course of immune surveillance and inflammation.

Antibodies, Monoclonal↗
PubMed1992

Classic, atypical, and anaplastic meningioma: three histopathological subtypes of clinical relevance.

This study correlates the histopathological classification of meningiomas with clinicopathological features of biological activity. A retrospective evaluation of 1799 surgical specimens of meningiomas from 1582 patients was made. The classic histopathological type, atypical meningiomas defined by increased cellularity and at least five mitotic figures in 10 high-power fields, anaplastic (malignant) meningiomas, and hemangiopericytic or papillary meningiomas were seen in 87.6%, 7.2%, 2.4%, and 2.8% of operations, respectively. The rates of recurrence in surgically treated patients with classic, atypical, anaplastic, and hemangiopericytic or papillary meningiomas were 6.96%, 34.6%, 72.7%, and 68.2%, respectively. The extent of surgery and the tumor size and site were studied in detail in 252 tumors of all histopathological types. Recurrences were rare in classic meningiomas after complete resection, whereas atypical and anaplastic tumors recurred after complete resection much more frequently. Classic meningiomas, hemangiopericytomas, and papillary meningiomas were smaller at surgery than atypical and malignant meningiomas. Atypical and malignant tumors were operated on more often in falcine and lateral convexity regions than were classic meningiomas. To support the authors' subjective categorization by a quantitative parameter related to proliferation, 112 meningiomas comprising all histopathological subtypes were investigated for staining of argyrophilic nucleolar organizer region proteins (Ag-NOR's). The Ag-NOR counts showed significant differences between classic, atypical, and anaplastic tumors but no significant differences between primary and recurrent tumors. Hemangiopericytomas and papillary meningiomas had lower Ag-NOR values than anaplastic meningiomas. A correlation of Ag-NOR numbers with the authors' histopathological scale of malignancy supports the introduction of atypical meningiomas with intermediate biological behavior on the classification scale between classic and anaplastic meningiomas. Overlapping of Ag-NOR numbers among all groups of malignancy may restrict the prognostic value of Ag-NOR counting in the individual case.

Aged↗