Biomedical subjects

Christian Matula

Publications and source records attributed to Christian Matula.

8 recordsLinked to original sources

PubMed2007

CT-MR image data fusion for computer assisted navigated neurosurgery of temporal bone tumors.

PURPOSE: To demonstrate the value of multi detector computed tomography (MDCT) and magnetic resonance imaging (MRI) in the preoperative work up of temporal bone tumors and to present, especially, CT and MR image fusion for surgical planning and performance in computer assisted navigated neurosurgery of temporal bone tumors. MATERIALS AND METHODS: Fifteen patients with temporal bone tumors underwent MDCT and MRI. MDCT was performed in high-resolution bone window level setting in axial plane. The reconstructed MDCT slice thickness was 0.8 mm. MRI was performed in axial and coronal plane with T2-weighted fast spin-echo (FSE) sequences, un-enhanced and contrast-enhanced T1-weighted spin-echo (SE) sequences, and coronal T1-weighted SE sequences with fat suppression and with 3D T1-weighted gradient-echo (GE) contrast-enhanced sequences in axial plane. The 3D T1-weighted GE sequence had a slice thickness of 1mm. Image data sets of CT and 3D T1-weighted GE sequences were merged utilizing a workstation to create CT-MR fusion images. MDCT and MR images were separately used to depict and characterize lesions. The fusion images were utilized for interventional planning and intraoperative image guidance. The intraoperative accuracy of the navigation unit was measured, defined as the deviation between the same landmark in the navigation image and the patient. RESULTS: Tumorous lesions of bone and soft tissue were well delineated and characterized by CT and MR images. The images played a crucial role in the differentiation of benign and malignant pathologies, which consisted of 13 benign and 2 malignant tumors. The CT-MR fusion images supported the surgeon in preoperative planning and improved surgical performance. The mean intraoperative accuracy of the navigation system was 1.25 mm. CONCLUSION: CT and MRI are essential in the preoperative work up of temporal bone tumors. CT-MR image data fusion presents an accurate tool for planning the correct surgical procedure and is a benefit for the operational results in computer assisted navigated neurosurgery of temporal bone tumors.

Adult↗

PubMed2005

Recurrent and metastatic clivus chordoma: systemic palliative therapy retards disease progression.

We report on a male patient with progressive and metastatic clivus chordoma treated over a period of 9 years by a multidisciplinary approach. Within the first 4 years, the patient underwent surgery four times. Thereafter, he received radiotherapy and subsequent chemotherapy. Stabilization of disease was achieved repeatedly for variable periods under local radiotherapy, systemic chemotherapy, immunomodulatory and anti-angiogenic therapy with isotretinoin and interferon-alpha, followed by thalidomide. Due to the occurrence of brain and lung metastases 8 years after initial diagnosis, liposomal doxorubicin was added to thalidomide. At the last follow-up control the patient had stable disease, with no progression of the intracranial tumor and regression of pulmonary metastases. He is in a good physical, psychological and neurological condition with a Karnofsky score of 80. Our observations show that multimodal therapy including a systemic palliative approach is associated with long quiescent intervals in recurrent chordoma and with regression of its metastases. Use of substances with high efficacy on tumor tissue and low toxicity, allowing long-term administration, seems promising in similar situations.

Chordoma↗

PubMed2003

Computer-enhanced stereoscopic vision in a head-mounted operating binocular.

Based on the Varioscope, a commercially available head-mounted operating binocular, we have developed the Varioscope AR, a see through head-mounted display (HMD) for augmented reality visualization that seamlessly fits into the infrastructure of a surgical navigation system. We have assessed the extent to which stereoscopic visualization improves target localization in computer-aided surgery in a phantom study. In order to quantify the depth perception of a user aiming at a given target, we have designed a phantom simulating typical clinical situations in skull base surgery. Sixteen steel spheres were fixed at the base of a bony skull, and several typical craniotomies were applied. After having taken CT scans, the skull was filled with opaque jelly in order to simulate brain tissue. The positions of the spheres were registered using VISIT, a system for computer-aided surgical navigation. Then attempts were made to locate the steel spheres with a bayonet probe through the craniotomies using VISIT and the Varioscope AR as a stereoscopic display device. Localization of targets 4 mm in diameter using stereoscopic vision and additional visual cues indicating target proximity had a success rate (defined as a first-trial hit rate) of 87.5%. Using monoscopic vision and target proximity indication, the success rate was found to be 66.6%. Omission of visual hints on reaching a target yielded a success rate of 79.2% in the stereo case and 56.25% with monoscopic vision. Time requirements for localizing all 16 targets ranged from 7.5 min (stereo, with proximity cues) to 10 min (mono, without proximity cues). Navigation error is primarily governed by the accuracy of registration in the navigation system, whereas the HMD does not appear to influence localization significantly. We conclude that stereo vision is a valuable tool in augmented reality guided interventions.

Depth Perception↗

PubMed2003

High-resolution three-dimensional contrast-enhanced blood oxygenation level-dependent magnetic resonance venography of brain tumors at 3 Tesla: first clinical experience and comparison with 1.5 Tesla.

RATIONALE AND OBJECTIVES: To evaluate the clinical potential of high-resolution 3D contrast-enhanced blood oxygenation level-dependent MR-Venography (CE-MRV) for primary brain tumors and metastases at 3 Tesla (T) in comparison to 1.5 T. METHODS: Eighteen patients with brain tumors were examined using CE-MRV after application of a standard dose of MRI contrast agent (0.1 mmol/kg gadodiamide). CE-MRV is based on a high-resolution 3D flow-compensated gradient-echo sequence with long echo times that uses the contrast-enhanced blood oxygenation level-dependent effect. This technique was performed using the same volume coverage and acquisition time at both field strengths after performing standard imaging sequences. RESULTS: The higher spatial resolution of CE-MRV at 3 T showed more details within and around tumors than at 1.5 T. Visibility was enhanced by stronger susceptibility weighting and higher intrinsic signal-to-noise at 3 T. Compared with standard imaging protocols, additional information characterized as tubular and nontubular hypointense structures were found within or around lesions on CE-MRV images. CONCLUSIONS: Acquisition of CE-MRV data at 3 T enables spatial resolution to be increased within the same measurement time and with the same volume coverage compared with 1.5 T, thus providing more detailed information. The method may also show the potential to estimate oxygen supply of tumors, especially at high field strengths.

Adult↗

PubMed2002

[Functional assessment before and after interventions on the optic chiasm system].

OBJECTIVES: In the course of a tumor in the area of the optic chiasm the optochiasmal system is often exposed to compressive and vascular irritations. This study deals with the functional results (visual acuity and visual field) before and after surgery based on the primary situation and morphology of the tumor in order to give a prognosis on this matter. METHODS: 62 patients (41 female, 21 male) suffering from tumors in the area of the optic chiasm were retrospectively reviewed. The duration of the follow-up was an average of 25.82 months, +/- 20.04. Among the tumors investigated there were 36 pituitary adenomas, 20 meningiomas, 4 craniopharyngiomas, one histiozytosis X and one gangliozytoma. For visual field examination the Humphrey Field Analyzer, program 30-2, was used. 34 tumors (54.8%) were excised by the transsphenoidal approach, 28 patients (45.2%) underwent transcranial surgery. RESULTS: As for visual acuity, of the 124 eyes 53 eyes (42.8%) improved after surgery, 64 eyes (51.6%) remained unchanged, 7 eyes (5.6%) deteriorated. Of the patients who underwent transsphenoidal surgery, 28 eyes (41.2%) improved after operation, 36 eyes (52.9%) remained unchanged, and 4 eyes (5.9%) worsened. In case of transcranial surgery, 25 eyes (44.6%) improved, 28 eyes (50.0%) remained unchanged, whereas 3 eyes (5.4%) worsened. There was a postoperative improvement in 53.2% of the visual fields, 37.1% remained unchanged, whereas 9.7% deteriorated. CONCLUSION: Both the transsphenoidal and transcranial approaches showed excellent visual outcome. Our experience indicates an excellent prognosis for improvement of visual acuity and visual fields provided an adequate procedure. Results depend, however, on the primary functional and morphological situation. In the case of a large supra-/parasellar tumor component a postoperative deterioration of vision may occur.

Adenoma↗

PubMed2002

Magnetic resonance imaging contrast enhancement of brain tumors at 3 tesla versus 1.5 tesla.

RATIONALE AND OBJECTIVES: To compare the diagnostic efficacy of a standard dose of MRI contrast agent in the evaluation of primary brain tumors and metastases using a high-field 3 tesla MR unit versus a 1.5 tesla MR unit. METHODS: Sixteen patients with brain tumors were examined at both field strengths using identical axial T1-SE protocols pre- and postcontrast (0.1 mmol/kg gadolinium), and postcontrast coronal 3D GRE with magnetization preparation (MP-RAGE), which was adjusted separately for each field strength. Evaluation of the images was performed quantitatively and, in the case of T1-SE images, also by visual assessment. RESULTS: Tumor-to-brain-contrast after gadolinium administration using statistical evaluation of MP-RAGE scans was significantly higher at 3 tesla (97.5) than at 1.5 tesla (46.3). The same was true for T1-SE sequences (93.0 vs. 72.1). Signal enhancement of the lesions in T1-SE sequences was not significantly different between both field strengths. CONCLUSIONS: Administration of a gadolinium contrast agent produces higher contrast between tumor and normal brain at 3 tesla than at 1.5 tesla.

Adult↗

PubMed2002

Traumatic arteriovenous fistula of the vertebral artery.

A 22-year-old woman sustained a stab wound injury of the right vertebral artery. Initial treatment with endovascular embolization using platinum coils in a local hospital could not stop the bleeding. The patient was transferred to our department in hypovolemic shock. Further angiography revealed an arteriovenous fistula. Open surgical revision occluded the vertebral artery and the patient recovered without neurological deficit.

Adult↗

PubMed2002

Recurrent angiofibroma invading the skull base--case report.

A 16-year-old male presented with a massive nasopharyngeal angiofibroma arising in the nasopharynx, nasal cavity, pterygopalatine fossa, and infratemporal fossa, and eroding the pterygoid process of the sphenoid bone. Neuroimaging showed the tumor had infiltrated the parasellar region from the middle cranial fossa and reached the cavernous sinus. The tumor was almost completely removed macroscopically by a modified transbasal approach.

Adolescent↗