Functional Brain Imaging Using MRI: An Emerging Tool for Drug Development and Clinical Trials

Brain functional magnetic resonance imaging using blood oxygen level dependent (BOLD) MRI, conventionally known as fMRI, has emerged as a method for evaluating cortical and subcortical neuronal function. At present, fMRI is used routinely for pre-surgical planning in the treatment of brain tumors and epilepsy, and is starting to be employed as a biomarker in drug development. fMRI works by detecting the changes in blood oxygenation level, which corresponds to neuronal synaptic activity, thereby revealing which parts of the brain are involved in a particular mental process. As a non-invasive method with high spatial and relatively high temporal resolution, fMRI has the potential to more precisely and accurately characterize brain function. This capability provides new methods for the evaluation of brain function, which can provide high quality, reproducible, quantitative information for the identification of clinical syndromes and development of targeted new therapies.

There have been numerous applications of BOLD fMRI reported in the clinictrials.gov repository – 305 studies are identified using the keyword ‘BOLD fMRI’ as of August, 2016. In the majority of these studies, fMRI is a supplementary data set that is collected in addition to primary study endpoints. Criteria for assessing fMRI results are not typically specified a priori. In one case, a study of the antidepressants citalopram and escitalopram, outcome measures are specified in terms of brain voxels showing greater activation with one drug compared to the other. Both qualitative and quantitative analysis of fMRI results is routinely employed. Of note, BOLD fMRI was used as the reference standard for comparison of another imaging technique (arterial spin labeled perfusion) for pre-surgical planning, which is an acknowledgement of the degree to which BOLD fMRI is accepted for this indication.

The hardware required to obtain fMRI data is widely available and consists of a 1.5 T or 3.0 T MRI scanner with a multichannel head coil and audio-visual devices for stimulus presentation, and feedback devices to record subjects’ responses. ECHO planar imaging is the most common sequence used in fMRI acquisition due to its fast whole brain sampling. The fMRI analysis is computationally complex. A brief overview of different approaches will be discussed. The analysis consists of two fundamental steps: pre-processing and statistical analysis. Preprocessing subroutines employ head motion correction to compensate for displacements in sampling brain areas, spin history corrections to minimize signal intensity changes, spatial and temporal filtering to increase signal to noise ratio and to remove the contribution of spurious frequencies from the signal of interest, and projection of an individual scan into a common atlas space. Statistical analysis, the process of identifying features relevant to processes under investigation, is carried out using a variety of approaches, including both parametric and nonparametric methods.

A typical fMRI study generates thousands of raw and analyzed images. Protocols supporting the data transfer from the MRI scanner to the designated processing station and specialized infrastructures for data management (e.g. storage, analysis and sharing) are essential to empower the precision and accuracy of the investigations.

This webinar will provide:

• Scientific and clinical research insights on the principles of BOLD fMRI and its application as a clinical tool and drug development biomarker
• Design of an fMRI study including appropriate pilot studies, development of a validated fMRI paradigm, and specification of quantitative and qualitative data analysis endpoints
• An overview of the challenges and limitations of performing fMRI evaluation under an Investigational New Drug Application for drug development

Speakers

Maria Laura Blefari, PhD, Biomedical Engineer, WorldCare Clinical

Dr. Maria Laura Blefari is a Biomedical Engineer working with WCC. She has investigated novel techniques based on real-time fMRI neurofeedback and simultaneous EEG-fMRI to reveal how changes in neural activity are linked to changes in motor behavior. During her post-doctoral studies at the Swiss Federal Institute of Technology de Lausanne, she collaboratively developed experimental protocols at 7T MRI for primary motor cortex characterization in normal and transhumeral amputees (primarily fMRI measurements and single-subject analysis.) Dr. Blefari received her MSc in Biomedical Engineering from Campus Bio-Medico University of Rome and her PhD in Biorobotics from Scuola Superiore Sant’Anna di Pisa.

Message Presenter

Mykol Larvie, MD, PhD, Physician, Department of Radiology, Director of Molecular Neuroimaging, Massachusetts General Hospital

Dr. Mykol Larvie is a physician in the Department of Radiology at Massachusetts General Hospital. He is a member of the Divisions of Neuroradiology and Nuclear Medicine and Molecular Imaging, and is the Director of Clinical Molecular Neuroimaging. He is an Instructor of Radiology at Harvard Medical School and in the Harvard-MIT Division of Health Sciences and Technology. Dr. Larvie is board certified in Diagnostic Radiology, Neuroadiology, and Nuclear Radiology by the American Board of Radiology. His clinical specialty is functional neuroimaging and his research is focused on the determinants of brain health and neurodegenerative disease.

Message Presenter