Functional magnetic resonance imaging: emerging clinical applications

Normative database of judgment of complexity task with functional near infrared spectroscopy--application for TBI

The ability to assess frontal lobe function in a rapid, objective, and standardized way, without the need for expertise in cognitive test administration might be particularly helpful in mild traumatic brain injury (TBI), where objective measures are needed. Functional near infrared spectroscopy (fNIRS) is a reliable technique to noninvasively measure local hemodynamic changes in brain areas near the head surface. In this paper, we are combining fNIRS and frameless stereotaxy which allowed us to co-register the functional images with previously acquired anatomical MRI volumes. In our experiment, the subjects were asked to perform a task, evaluating the complexity of daily life activities, previously shown with fMRI to activate areas of the anterior frontal cortex. We reconstructed averaged oxyhemoglobin and deoxyhemoglobin data from 20 healthy subjects in a spherical coordinate. The spherical coordinate is a natural representation of surface brain activation projection. Our results show surface activation projected from the medial frontopolar cortex which is consistent with previous fMRI results. With this original technique, we will construct a normative database for a simple cognitive test which can be useful in evaluating cognitive disability such as mild traumatic brain injury.

Multisite neuroimaging trials

PURPOSE OF REVIEW

The intent of this study is to review trends in multicenter neuroimaging trials and their value for research and implications for clinical treatment.

RECENT FINDINGS

The rise in availability of MRI for detecting disorders in the living brain has made it an attractive technology for assessing neural structure and function in a number of prominent diseases. Geographic factors underlying diseased populations coupled with complementary neuroimaging research programs have led to an increase in multicenter neuroimaging trials and consortia. Neuroimaging has become a major focus for multiinstitutional research in progressive changes in brain architecture, proxy biomarkers of treatment response, and the effects of disease on patterns of cognitive activation and connectivity. Notable consortia and research trial studies have focused on Alzheimer's disease, pediatric brain cancer, and fetal alcohol syndrome, in addition to multiinstitutional collaborative programs for mapping the normal brain. Such large-scale efforts necessitate close coordination of image data collection protocols, ontology development, computational requirements, concerted data archiving, and sharing.

SUMMARY

Multicenter neuroimaging trials, consortia, and collaboratives enable the acquisition of large-scale, purpose-driven datasets that can then be used by the broader community to model and predict clinical outcomes as well as guide clinicians in selecting treatment options for neurological disease.

Functional MR imaging: paradigms for clinical preoperative mapping

Clinical applications of functional MR imaging include mapping of brain functions in relationship to intracranial tumors, seizure foci, or vascular malformations to determine the risk for performing surgical excision, the need for intraoperative mapping during excision, and selecting the optimal surgical approach to a lesion. A variety of paradigms are used to produce a blood-oxygen-level-dependent response in various brain regions, which can be identified with functional MR imaging. The paradigms used include active motor, language, or cognitive tasks, and passive tactile, auditory, or visual stimuli. Activation usually indicates the location of eloquent cortex. Lack of function in a region cannot be assumed when functional MR imaging shows absence of activation within the region.