Diagnostic and surgical procedures

Visualisation of brain functions

• Functional Magnetic Resonance Imaging (fMRI): Visualisation of brain functions (e.g. language, motor skills, memory) in relation to their location in relation to a mass such as a brain tumour, brain metastasis or vascular malformation.
• Resting State Functional Magnetic Resonance Imaging (rsfMRI): Complex procedure used to image brain function in special patient populations (infants, elderly and/or severely impaired patients, patients with intellectual disabilities, patients under anaesthesia, or patients with a language barrier).
• Diffusion Tensor Imaging (DTI) and Tractography: Three-dimensional visualisation of structural connections in key functional brain networks, such as the language or motor networks.

Mapping of tumour biology

• Positron emission tomography (PET): A special imaging technique used in nuclear medicine to detect and visualise active tumour regions in order to optimise resection planning. Different PET methods are used depending on the type of tumour (e.g. F-18 fluoroethyltyrosine PET for brain tumours or DOTATOC PET for meningiomas).

This is an objective test of brain functions such as language, memory and visual-spatial ability. If disorders or abnormalities are detected, this may affect the course of treatment. The examinations are carried out before and after an operation for a brain tumour or vascular malformation and, if necessary, during the course of treatment.

Pre-surgical functional multimodal imaging uses a variety of radiological and nuclear medicine techniques to gather information. These include fMRI (functional magnetic resonance imaging), DTI (diffusion tensor imaging) and PET (positron emission tomography).

All the results are then combined with anatomical imaging data from MRI or CT scans, such as the location of blood vessels or the size and extent of the tumour. All the data is then visualised in three dimensions using innovative software we have developed (NeuroVis). This allows the surgeon to familiarise himself with the exact location of the tumour in relation to important brain structures and to plan the operation with confidence.

During surgery, this information can also be used to guide the brain with millimetre precision using a navigation system (similar to GPS). This allows the surgeon to remove a tumour as gently as possible while preserving important brain functions.

In selected cases, we use the option of operating while the patient is awake to avoid post-operative speech and movement disorders. In Regensburg, we have developed a unique method without anaesthesia, in which local anaesthesia of the skin is sufficient, as the brain itself has no pain receptors. During the operation, brain functions such as speech and movement can be controlled in order to remove the tumour as completely as possible without endangering functions.

For example, during surgery, patients perform simple speech or movement tasks while the neurosurgeon electrically stimulates the brain at various points in the operating theatre. This stimulation helps the surgeon determine which regions of the brain are safe to operate on.

Throughout the procedure, the patient receives seamless and intensive care from an experienced and specialised team of neurosurgeons and anaesthetists.

Fluorescent dyes are suitable for most tumours, but also for aneurysms and angiomas (see vascular neurosurgery, to ensure gentler and, in the case of tumours, more complete removal. After administration, these substances rapidly accumulate in the target tissue and fluoresce under specially filtered light from the operating microscope. This makes it much easier to distinguish the fluorescent tumour area from normal brain tissue. Our clinic has many years of experience and the modern technical equipment to stock and apply each of these dyes individually.

Confocal microscopy (Convivo) - "Digital biopsy"

Confocal laser scanning microscopy (Convivo) is a novel method for visualising cellular and structural tissue characteristics during brain surgery. In addition, we are currently conducting scientific studies to determine whether this method can be used to reliably identify the type of brain tumour during surgery. This could significantly change the surgical procedure by eliminating the need for invasive frozen section analysis.