Biomedical subjects

F K Albert

Publications and source records attributed to F K Albert.

At least 19 recordsLinked to original sources

PubMed2001

Increased chromosomal imbalances in recurrent pituitary adenomas.

Eight pituitary adenomas (four gonadotroph cell adenomas, three prolactin cell adenomas, one null cell adenoma) and their respective recurrences in the same patients were studied by comparative genomic hybridization. Chromosomal imbalances were found in seven of eight patients affecting two of eight primary and seven of eight recurrent tumors. Overall, pituitary adenomas showed an average of 1.6 chromosomal imbalances per primary and 3.4 per recurrent tumor (P < 0.01). Prolactin cell adenomas showed an average of 4.3 chromosomal changes per primary and 6.3 per recurrent tumor, which were significantly more common than in gonadotroph cell adenomas (0 vs 1.7 changes; P < 0.05) and the null cell adenoma (0 vs 1.0 changes; P < 0.05). The most common changes were gains of 4q (in three of eight recurrences), 5q, and 13q (in two of eight recurrences each) as well as losses of chromosome 2 (in both primary and recurring tumors of two patients), 1p, 8q, 10, and 12q (in two of eight recurrences). Minimal common regions associated with recurrent adenomas were gains of 4q31.2-34 (three recurrences), 5q14-23 and 13q21-31 and losses of 12q24.3-qter (two recurrences each). The average MIB-1 proliferation indices were 1.2% for primary and 1.9% for recurrent adenomas (P < 0.005). Our findings suggest that acquisition of certain chromosomal imbalances is related to and may underlie adenoma recurrence.

Adult↗

PubMed2000

The benefit of neuronavigation for neurosurgery analyzed by its impact on glioblastoma surgery.

Neuronavigation, today a routine method in neurosurgery, has not yet been systematically assessed in direct comparison with conventional microsurgical techniques. The aim of the present study was the direct comparison of the impact of neuronavigation on glioblastoma surgery regarding time consumption, extent of tumor removal and survival. For each of 52 patients operated for primary glioblastoma with neuronavigation, a patient operated on without navigation was matched. Completeness of tumor resection, including volumetric analysis, was examined by early post-operative MRI. Operating and survival times were obtained for all patients. At a rate of 86.5%, surgeons' opinions about neuronavigation were positive. Operating times were identical in the two groups, while preparation times were 30.4 min longer with navigation. Radiological radicality was achieved in 31% of navigation cases vs. 19% in conventional operations. The absolute and relative residual tumor volumes were significantly lower with neuronavigation. Radical tumor resection was associated with a highly significant prolongation in survival (median 18.3 vs. 10.3 months, p < 0.0001). Survival was longer in patients operated on using neuronavigation (median 13.4 vs. 11.1 months). Neuronavigation increases radicality in glioblastoma resection without prolonging operating time. Regarding the problem of brain shift, neuronavigation should be optimized by intraoperative real-time imaging.

Adult↗

PubMed2000

Laser-induced fluorescence detection of malignant gliomas using fluorescein-labeled serum albumin: experimental and preliminary clinical results.

To delineate the tumor margins of malignant gliomas laser-induced fluorescence detection technique was applied using 5-aminofluorescein-albumin as the fluorescent dye. The 5-aminofluorescein was linked to serum albumin (= AFlc-SA) as a cumulative protein label using residualizing markers. In a C6-glioma model the biodistribution and pharmacokinetics of the injected dye were investigated by labeling the protein conjugate with 111In-DTPA. Twenty-four hours after intravenous injection of the dye, fluorescence was activated by an argon laser and inspected in the C6-gliomas. Histological examinations were performed to compare the microscopic margins of the fluorescence-stained tumors with hematoxylin/eosin. The tumor uptake 24 h after dye injection was 23-fold higher than in the surrounding brain. Fluorescence inspection under laser activation demonstrated clearly stained and sharply demarcated tumors. The microscopic borders of the tumors corresponded exactly with the fluorescence, also demonstrating intracellular tumor uptake of the dye. In a preliminary study, three patients with malignant gliomas were operated using laser-induced fluorescence detection technique after injection of AFlc-SA. In all patients, the borders of the malignant gliomas were clearly stained by AFlc-SA during surgery. Laser-induced fluorescence imaging using the albumin conjugate AFlc-SA may be a promising method for delineating tumor margins which are hard to detect under the operating microscope alone.

Animals↗

PubMed1999

Pericallosal artery aneurysm originating from a "supreme anterior communicating artery".

Report on the rare case of a ruptured pericallosal aneurysm originating from an atypic communicating segment between both distal A2 arteries, called the 'supreme anterior communicating artery'. The neurosurgeon should be aware of this rare vascular anomaly that might be angiographically occult and raise unexpected intraoperative difficulties.

Adolescent↗

PubMed1998

[Modifications of fronto-orbital osteotomy as an approach to the anterior and middle skull base].

Various extracranial, intracranial and combined extra-intracranial approaches have been described for the surgical therapy of tumours of the anterior and medial cranial base. A combined extra-intracranial approach is indicated in cases in which the cranial base tumour spreads out intracranially and at the same time into the main nasal cavity, the paranasal space and/or the orbits. These tumours of the skull base can be surgically removed by two standardised modifications of the fronto-orbital osteotomy--the fronto-orbito-nasal and the fronto-orbito-zygomatic osteotomy. The advantage of these surgical techniques in comparison with other methods is that they permit a good extracranial and intracranial view with only minimal brain trauma. Generally, additional transfacial incisions are unnecessary. The operative techniques are described and the results of 108 cases of tumours of the skull base shown.

Craniotomy↗

PubMed1998

[Effect of brain edema on the recurrence pattern of malignant gliomas].

PURPOSE: To assess the influence of initial preoperative brain edema in malignant gliomas on regrowth patterns. SUBJECTS AND METHODS: 79 patients with histologically verified supratentorial malignant glioma were prospectively studied by magnetic resonance imaging (MRI) before and every 2-3 months after surgery. The median follow-up time was 11 months. We correlated the configuration of the initial vasogenic edema on T2-weighted images with tumor regrowth patterns on contrast-enhanced T1-weighted images. RESULTS: 35/47 tumor regrowths (75%) imitated the initial edema configuration, while 11/47 occurred within the initial tumor bed; in one case tumor recurrence was multilocal. CONCLUSION: In glioblastoma, tumor regrowth patterns correlate positively with the configuration of the initial vasogenic brain edema. The initial, "presurgical" peritumoral edema should thus be considered when planning further treatment.

Adult↗

PubMed1998

Preoperative planning and intraoperative navigation in skull base surgery.

Experience with the commercially available, 3-D navigation systems Viewing Wand (ISG, Mississauga, Ontario, Canada) and SPOCS (Aesculap, Germany) in skull base surgery is presented. Having meanwhile been tested in over 60 clinical trials, the systems achieved an accuracy of < or = 2.7 mm which, at the moment, we deem sufficiently acceptable to proceed with their clinical evaluation. There was no difference in intraoperative accuracy between the mechanical and the optical navigation systems. The systems proved to be very helpful in identifying the extent of the tumours and in visualizing the proximity of vital structures. 3-D-planning, simulation and intraoperative navigation especially facilitates surgery in anatomically complicated situations, without risk of damaging neighbouring structures. The SPOCS (Surgical Planning and Orientation Computer System) revealed a considerably improved flexibility in handling and a better integration into the surgical procedure in comparison with the relatively inflexible and space-demanding Viewing Wand arm. Especially, the 'offset' function of the SPOCS offers the possibility of a virtual elongation of the instrument and thus, in combination with the on-line visualization of the corresponding images, of a 'look ahead' operation. By using computer-assisted simulation and navigation systems, we can expect quality improvement and risk reduction. More extensive and radical interventions seem possible.

Computer Simulation↗

PubMed1998

Modified Headholder and operating table for intra-operative MRI in neurosurgery.

In order to facilitate intra-operative use of magnetic resonance imaging (MRI) in neurosurgery an MRI-compatible headholder was developed and adapted to a modified MR-couch simultaneously serving as tabletop for the operating table. To allow shock-free transport into the scanner the wheels of the operating table were replaced by an air cushion mechanism. In 75 procedures the system proved to be reliable and safe. Image quality was not impaired by the fixation device. With growing routine the transfer became straightforward, requiring approximately 10 min. Intra-operative MRI is thus made possible with minimal changes to the standard surgical environment. Its benefit however, still remains to be critically investigated.

Equipment Design↗

PubMed1998

Neuronavigation--first experiences with three different commercially available systems.

Growing interest in neuronavigation also referred to as frameless stereotaxy has led to the development of various navigational devices employing different localization methods. In 152 procedures the authors have used neuronavigation. Cases included 89 intracranial- and 26 skull base tumours, 9 biopsies, 21 vascular and 7 functional procedures on 144 patients since July 1993. In 75 cases the lesions were located in eloquent areas. In 82% (124) MRI, 13% (18) CT and 5% (8) both imaging methods were employed. Three neuronavigational devices with different localization methods were used for the procedures. The Viewing Wand (VW, ISG, Canada), a multijointed arm was used in 101 procedures. In 15 cases the SPOCS (Aesculap, Germany) consisting of cameras detecting infrared light from LED's mounted on instruments and in 51 cases the microscope-integrated MKM (ZEISS, Germany) was investigated, 15 times two systems were used simultaneously. Mean time necessary for preoperative registration was 23 +/- 13 min (VW), 21 +/- 16 min (SPOCS) and 27 +/- 22 min (MKM) respectively. The mean accuracy of registration measured as RMS was 2.9 +/- 1.2 mm (VW), 3.3 +/- 0.9 mm (SPOCS) and 3.1 +/- 1.0 (MKM) respectively. Regarding intraoperative handling the VW was found to be a robust but sometimes bulky and hindering device whereas the SPOCS was more flexible but with the need of unobstructed visibility between cameras and pointers. The MKM without these restrictions required training to get used to handling.

Adolescent↗

PubMed1997

Image guided excision of a ruptured feeding artery "pedicle aneurysm" associated with an arteriovenous malformation in a child: case report.

Excision of a ruptured aneurysm located at a lenticulostriate feeding artery associated with an arteriovenous malformation was performed using image guided neuronavigation in an 8-year-old child. The management of this lesion, which is rare in childhood, demonstrates the potential of combining frameless stereotaxy for precise target approach with conventional open microneurosurgery to minimize morbidity. Because of the unavoidable shifting of the brain that occurs during surgery, a catheter pointing towards the dome of the aneurysm was placed using image guidance prior to insertion of spatulae.

Aneurysm, Ruptured↗

PubMed1997

Intraoperative diagnostic and interventional magnetic resonance imaging in neurosurgery.

OBJECTIVE: The benefits of intraoperative magnetic resonance (MR) imaging for diagnostic and therapeutic measures are as follows: 1) intraoperative update of data sets for navigational systems, 2) intraoperative resection control of brain tumors, and 3) frameless and frame-based on-line MR-guided interventions. The concept of an intraoperative MR scanner in the sterile environment of operating theater is presented, and its advantages, disadvantages, and limitations are discussed. METHODS: A 0.2-tesla magnet (Magnetom Open; Siemens AG, Erlangen, Germany) inside a radiofrequency cabin with a radiofrequency-shielded sliding door was installed adjacent to one of the operating theaters. A specially designed patient transport system carried the patient in a fixed position on an air cushion to the scanner and back to the surgeon. RESULTS: In a series of 27 patients, intraoperative resection control was performed in 13 cases, with intraoperative reregistration in 4 cases. Biopsies, cyst aspirations, and catheter placements (mainly frameless) were performed under direct MR visualization with fast image sequences. The MR-compatible equipment and the patient transport system are safe and reliable. CONCLUSION: Intraoperative MR imaging is a safe and successful tool for surgical resection control and is clearly superior to computed tomography. Intraoperative acquisition of data sets eliminates the problem of brain shift in conventional navigational systems. Finally, on-line MR-guided interventional procedures can be performed easily with this setting. As with all MR systems, individual testing with phantoms, application of correction programs, and determination of the optimal amount of contrast media are absolute prerequisites to guarantee patient safety and surgical success.

Adult↗

PubMed1997

Image-guided neurosurgery with intraoperative MRI: update of frameless stereotaxy and radicality control.

Intraoperative shifts and resulting inaccuracies have been a concern in frame based and frameless stereotactically guided interventions, particularly in open microsurgical procedures. Trying to solve this problem, we developed a method to perform intraoperative MRI (0.2 tesla, Magnetom Open) and use intraoperatively acquired data sets to update neuronavigation. In 21 patients, intraoperative images could be used to reference navigation (mean accuracy of 0.83 +/- 0.31 mm). The operation was continued in 10 cases to resect detected tumor remnants using navigation, leaving 4 patients (19%) with residual tumor postoperatively. We showed that update of frameless stereotaxy to compensate for brain shift is feasible and might increase the number of cases where radiologically complete resection can be achieved.

Equipment Design↗

PubMed1997

Intraoperative magnetic resonance imaging to update interactive navigation in neurosurgery: method and preliminary experience.

We report on the first successful intraoperative update of interactive image guidance based on an intraoperatively acquired magnetic resonance imaging (MRI) date set. To date, intraoperative imaging methods such as ultrasound, computerized tomography (CT), or MRI have not been successfully used to update interactive navigation. We developed a method of imaging patients intraoperatively with the surgical field exposed in an MRI scanner (Magnetom Open; Siemens Corp., Erlangen, Germany). In 12 patients, intraoperatively acquired 3D data sets were used for successful recalibration of neuronavigation, accounting for any anatomical changes caused by surgical manipulations. The MKM Microscope (Zeiss Corp., Oberkochen, Germany) was used as navigational system. With implantable fiducial markers, an accuracy of 0.84 +/- 0.4 mm for intraoperative reregistration was achieved. Residual tumor detected on MRI was consequently resected using navigation with the intraoperative data. No adverse effects were observed from intraoperative imaging or the use of navigation with intraoperative images, demonstrating the feasibility of recalibrating navigation with intraoperative MRI.

Adult↗

PubMed1996

[Does the administration of a high dose of a paramagnetic contrast medium (Gadovist) improve the diagnostic value of magnetic resonance tomography in glioblastomas?].

PURPOSE: To assess the efficacy of high-dose contrast enhanced magnetic resonance imaging (MRI) in detection and delineation of infiltrating tumour in glioblastoma. MATERIAL AND METHODS: In a phase II clinical trial 14 patients with suspected supratentorial glioblastoma underwent MRI with Gd-DO3A-butriol (Gadovist, Schering AG, Berlin) with doses of 0.1 up to 0.3 mmol/kg. RESULTS: Increasing the dose of Gd-DO3A-butriol resulted in improved enhancement (14/14) and better delineation of infiltrating tumour (9/14) up to 2 cm beyond enhancement after standard dose. In two of the 9 patients additional enhancement in the peritumoural oedema was only seen after the third injection. CONCLUSIONS: Successful surgery requires precise preoperative delineation of tumour borders. After high-dose MRI it might be possible to select those patients who would benefit from more radical attempts at eradicating the macroscopic as well as most of the microscopic compartment of glioblastoma.

Contrast Media↗

PubMed1996

Intraoperative computer-assisted neuronavigation in functional neurosurgery.

The clinical experience with a frameless computer-assisted neuronavigational system (ISG. Canada) used in functional neurosurgery is described. The advantage of image-guided surgery is stressed for functional procedures of the cortex with delineation of the gyral pattern, e.g. motor cortex stimulation and procedures at the base of the skull with triplanar and three-dimensional reconstruction of the bony landmarks. A general use of the device for aiming at subcortical targets cannot be recommended. Limitations are the accuracy (< or = 2.2 mm) and software deficiencies and the lack of a reliable fixation of the position sensing arm (wand).

Cerebral Cortex↗

PubMed1996

Coil placement after clipping: endovascular treatment of incompletely clipped cerebral aneurysms. Report of two cases.

In up to 4% of patients whose aneurysms are microsurgically clipped, there is an expected or unexpected aneurysm residuum. The authors describe two patients in whom surgical clipping did not result in complete obliteration of the aneurysm sac and in whom a second operation was not believed to be the solution to the problem. In both patients complete occlusion of the aneurysm residuum was achieved via an endovascular approach. Using the Guglielmi detachable coil system, it was possible to place two platinum coils selectively into the aneurysms. The endovascular approach may be a good treatment option for all patients in whom surgical clipping does not result in complete obliteration of the aneurysm sac and reoperation is contraindicated or unacceptable to the patient.

Adult↗

PubMed1996

Clinically distinct subgroups of glioblastoma multiforme studied by comparative genomic hybridization.

Studies investigating genetic alterations potentially constituting prognostic factors in glioblastoma multiforme (GBM) have centered mainly around amplification events. Comparative genomic hybridization (CGH) is a recent molecular cytogenetic technique that allows the detection of chromosomal imbalances and amplification sites in tumor DNA prepared from fresh or archival material. A group of 94 patients with GBM underwent surgery followed by a standard course of radiotherapy. Neuroradiologic monitoring with gadolinium-enhanced serial magnetic resonance imaging was applied to study the radiologically progression-free interval (RPFI) and tumor regrowth velocity. These parameters provided a clinical estimate of the postoperative tumor regrowth kinetics and yielded two clinically distinct groups. The most pronounced cases were selected from each group, i.e., those with the most favorable and unfavorable prognosis. Two subgroups with a statistically significant difference in RPFI (p < 0.001, Mann-Whitney U test) containing 10 patients each were formed: Subgroup A (slow tumor regrowth kinetics) and subgroup B (fast tumor regrowth kinetics). For a search of chromosomal alterations that might be correlated with tumor regrowth kinetics, we applied CGH to formalin-fixed, paraffin-embedded tumor tissue from these 20 patients. Except for autosomes 18 and 21, all chromosomes were involved at least once in copy-number aberrations. Events commonly associated with GBM, i.e., gains of chromosome 7, complete and partial losses of 9p, 10, and 22q, were not distributed differently between the two subgroups. The following differences were noticeable. Gains (including amplifications) of 12q14-q21 and of 19 were observed more often in subgroup A. Losses of 6q16-qter and parts of 13, and gains of 20, were more frequent in subgroup B. RPFI was significantly shorter for patients without amplification sites than for patients with gene amplification. RPFI did not differ significantly between patients with or without 7p12 amplification, where the epidermal growth factor receptor gene is localized. New amplification sites for GEM tumors were revealed at 11q13 and 11q22-q23. Loss of chromosome 10 was restricted to bands 10q25-q26 in one case. Although differences in the copy-number karyotypes of patients with slow and fast postoperative tumor-regrowth kinetics were noted, the present CGH study did not reveal any single alteration useful as a prognostic factor. In particular, these data do not support the assumption that patients suffering from GBM with amplification events would have a poorer prognosis than others.

Adult↗

PubMed1996

Case report. Microcephalic osteodysplastic primordial dwarfism type II: a child with unusual symptoms and clinical course.

UNLABELLED: We report on a 13-month old boy with microcephalic osteodysplastic primordial dwarfism (MOPD), whose radiographic signs correspond with type II of this entity. Some of his clinical signs, such as the anomalies of the external genitalia and the urinary tract, are common to this subgroup of MOPD, but he also shows unusual clinical signs including bilateral knee dislocation and hypoplasia of the anterior corpus callosum. His clinical course was unusual with several episodes of breathing difficulties and increased intracranial pressure secondary to craniosynostosis at the age of 16 months. After front-orbital advancement for the treatment of brachycephaly, his psychomotor development improved remarkably. CONCLUSION: MOPD type II may have a wider range of expression than previously delineated.

Abnormalities, Multiple↗