Université de Genève

Neuroscience center

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Group leader: Sven Haller

Group name: Clinical Neuroradiology and Advanced Neuroimaging Techniques

Affiliation: University Hospital

Research activities:

We aim to develop and optimize advanced neuroimaging techniques - with respect to potential clinical applications. Current fields of research are: - real-time fMRI: this technique allows to learn voluntary control over localized brain areas by means of operant conditioning. We successfully applied this very recent technique to the clinical setting of tinnitus in a pilot study. Patients with tinnitus successfully down-regulated the excess auditory activations, which are associated with chronic tinnitus. This lead to an improvement of the tinnitus symptoms - at least in a proportion of patients. This novel technique needs important adaptations and optimizations for clinical applications, which is the subject of an ongoing research project - CO2BOLD: this technique permits a non-invasive assessment of the cerebral perfusion reserve at a high spatial resolution of the brain parenchyma, thus taking into account collateral flow. This technique identified patients at risk for the development of peri-interventional micro ischemic lesions in patients with symptomatic high-grade stenoses of the internal carotid artery. Current research assesses the cerebral perfusion reserve in dementia, notably Alzheimer disease. - Computer-aided advanced image analysis for individual classification: many diseases such as Alzheimer or psychosis have associated morphologic brain changes. These changes are however too small, in particular in light of the normal variation in brain anatomy, to be detected by the eye. The aim of advanced systematic image analysis is to contribute to an individual classification of patients. A recent study individually classified patients at risk for psychosis based on cortical thickness. Ongoing research aims to include also other type of brain imaging parameter, such as white matter diffusion tensor imaging (DTI) and different classification algorithms.

Selected Publications:

  • Haller S, Birbaumer N Veit R (2010): Real-time fMRI feedback training may improve chronic tinnitus. Eur Radiol 20: 696-703.
  • Haller S, Bonati LH, Rick J, Klarhofer M, Speck O, Lyrer PA et al. (2008): Reduced Cerebrovascular Reserve at CO2 BOLD MR Imaging Is Associated with Increased Risk of Periinterventional Ischemic Lesions during Carotid Endarterectomy or Stent Placement: Preliminary Results. Radiology 249: 251-258.
  • Haller S, Borgwardt SJ, Schindler C, Aston J, Radue EW Riecher-Rossler A (2009): Can cortical thickness asymmetry analysis contribute to detection of at-risk mental state and first-episode psychosis? A pilot study. Radiology 250: 212-221.

Contact:
Geneva University Hospital
Service neuro-diagnostique et neuro-interventionnel DISIM
Email: sven (dot) haller (at) hcuge (dot) ch