Philadelphia University + Thomas Jefferson University

Integrated Magnetic Resonance Imaging Center

Imaging graphic

The Jefferson Integrated Magnetic Resonance Imaging Center (JIMRIC) provides enterprise-wide clinical and research support for investigators involved in magnetic resonance (MR) imaging of the human brain and central nervous system (CNS), cardiac, and musculoskeletal systems. Our technical specialists provide advanced imaging consultation on MRI pulse sequence development, optimization and study protocol definition, as well as computational post-processing of MR data to create clear, useful images of relevant structures and functions.

The Center has a special interest in functional MRI (fMRI), which assesses the physiological activity of a given body-area. In the case of JIMRIC, the fMRI capacity is used to analyze neural activity, particularly in the white matter of the brain, which connects the major “processing” nodes of the cortex. Being able to have an accurate picture of an area’s functional connectivity is important in determining the location of an injury, as well as the course a neurosurgical intervention might take. When combined with a structural analysis of the brain or other organ system, fMRI offers a potent diagnostic capacity.

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Structural (L) and functional (R) images of the spinal cord

While imaging optimization and support of clinical activities is one arm of what we do, the development and implementation of functional imaging techniques as potential biomarkers for analyses of various pathologies is our expertise. Our experts support numerous departments across the University and Hospital, including: Radiology, Psychiatry, Psychology, Neuroscience, Neuro-Oncology, Neurology, OT/PT and Neurosurgery.

The Center is also a resource for researchers looking to develop new grants in the area of brain and spine disorders. The Center will collaborate with any departments aiming to build a robust MR imaging methodology into their research studies in testing their hypotheses, particularly in the investigation of the Central Nervous System non-invasively in humans.

Ongoing Research Projects

For years our interest has been focused on the characterization of pediatric SCI using reduced field of view DTI, which allows for the quantification of water diffusion in neurons and could serve as a potential biomarker for diagnosis. In addition we are also investigating Diffusion Kurtosis Imaging (DKI), Neurite Orientation Density Dispersion Imaging (NODDI), Magnetization transfer (MT), and Cord Atrophy using automated spinal cord sectional area measurements (SCCSA) of the human spinal cord. We have used these techniques to study the normal and injured pediatric spinal cord and are in the process of developing imaging biomarkers as an adjunct to current diagnostic methods in spinal cord injured patients. The laboratory is also working towards development of a pediatric spinal cord template and multispectral analysis of the cord. This template, essentially a composite or “average” of many MR images of the pediatric spine, will serve as a benchmark clinicians can use to diagnose SCI. We are also investigating the relationship between the integrity of the CNS and SCI patients’ clinical neurologic presentation and functional ability in adult spinal cord injured patients.

Background

Tractography is a three-dimensional modeling technique that has been used for the past two decades to visualize the connections between different parts of the brain. This method is based on diffusion magnetic resonance imaging (dMRI), which images the way in which water moves within the brain. We can assume this path represents the connections between cells in the brain—that it represents axons and white matter pathways.

As the only non-invasive method of visualizing white matter tracts in living humans, dMRI’s applications have continued to expand. It is used clinically for planning surgeries in patients with brain tumors and epilepsy; and there is immense potential for use as a diagnostic and prognostic tool in stroke, multiple sclerosis, Alzheimer’s disease, and spinal cord disorders.

Current MRI technology is capable of imaging down to a resolution of a 1mm cube (known as a voxel). However, since white matter tracts are smaller than 1mm, each voxel can contain many white matter tracts, which may travel in different directions. In an attempt to image these tracts, newer MRI sequences are capable of capturing a greater number of directions within a single voxel. In order to make sense of this additional information, techniques for modeling the fibers have become more complex. Since these models are based on statistics and complex mathematical equations, none of which have been proven experimentally in the living human brain.

The Jefferson Comprehensive Epilepsy Center, regularly treats patients with drug-resistant epilepsy. In evaluating these patients for surgery, physicians routinely implant stereoelectroencephalography (stereo EEG) electrodes into the brain to determine where seizures are originating, where they are spreading and how this path is related to important brain areas. Patients are usually in the hospital with these implanted electrodes for an average of two weeks before physicians have enough information to make a decision about surgery.

This practice provides a unique opportunity to study the electrical recordings of a living human brain by using them to define pathways of electrical activity and showing how different brain regions communicate with each other. With electrodes implanted both in gray matter (neurons) and white matter (axons), it is possible to see how electrical activity flows out of one group of cells, along a white matter bundle, and to another group of cells.

Our Project

This will be the first study to use electrical recordings from the brain to refine methods of tractography. By mapping the multiple pathways of this electrical activity, we plan to create a standard against which current tractography modeling techniques can be compared.

The main idea behind is that maps of electrical activity in the brain can be used to refine methods of imaging white matter tracts in living human subjects. Specifically, we intend to use these maps of electrical activity to gain a better understanding of three methods of dMRI-based tractography: diffusion tensor imaging (DTI), high-angular resolution diffusion-weighted imaging (HARDI), and neurite orientation dispersion and density imaging (NODDI).  

The PET-MR scanner in Villanova is among only a handful of such machines in the country and has the capacity to track function versus receptor occupancy for a variety of cognitive tasks. Our researchers are now using this device to study the mechanisms of two “integrative” approaches to managing stressful and traumatic events in cancer patients using advanced functional neuroimaging methods such as fMRI, resting state and diffusion tensor imaging (DTI).

Our focus here is on the use of blood-oxygen-level dependent (BOLD) and diffusion-based imaging techniques for integration into the operating room as a functional roadmap for surgical planning.  To accomplish this, we are developing image post-processing pipelines to facilitate the automated generation of results for areas such as motor/language mapping, in patients with brain tumors, Parkinson’s (deep brain stimulation) and epilepsy.

Neuronal loss and dopamine depletion alters motor signal processing and propagation between the cortical motor areas, the basal ganglia and the thalamus, resulting in the motor manifestation of Parkinson’s disease (PD). Abnormal neural connections and activity within these circuits have been demonstrated in animal models of PD, as well as in humans suffering from movement disorders. We aim to better understand the changes in functional connectivity (FC) and anatomical connectivity (AC) that occur with disease progression, and are exploring how both FC and AC of cortico-basal-ganglia-thalamic circuits change in patients with advanced PD. Our findings to date have helped to translate our understanding of these networks from animal studies to human patients.

We believe that advanced MR imaging may reveal a useful imaging biomarker that can help to predict response to treatment in patients suffering from PD.

Background

Epilepsy is a chronic condition characterized by recurrent seizures and affecting over three million Americans. One million (30%) of these patients have seizures that cannot be controlled through medication. Poorly-controlled epilepsy is disabling, and leads to unemployment, recurrent injury and a high risk of death.

In patients with drug-resistant epilepsy, a series of tests may be performed to help locate the origin of the seizures and provide clinicians with important information about the brain in order to consider a surgical intervention. Clinical teams assemble as many clues as possible, drawing on fields such as neurology, neuropsychology, neuroradiology, neuroelectrophysiology, and neurosurgery. Each element, by itself, is of limited use, but taken as a whole, these tests can produce a powerful diagnostic tool.

Our Project

Much of this data is acquired at different stages of a patient’s diagnosis and treatment, and there is no commercially-available system that permits the acquisition and storing of multimodal information. Consequently, data acquired at one stage of the patient's evaluation by one part of the clinical team cannot easily be shared with another. This also prevents aggregating data acquired from large populations at multiple clinical sites, and limits the extent to which best practices or expertise can be transferred between these sites as well.

A research system that addresses similar issues from deep brain stimulation (DBS) has been developed at Vanderbilt with NIH support and integrated in the clinical flow at Jefferson. In a collaborative effort with researchers at Vanderbilt, we are working on an analogous system capable of supporting and streamlining the processing of the vast amount of multimodal data that must be processed in order to make appropriate clinical decisions in patients with epilepsy.

To learn more, contact
Director
Feroze Mohamed, PhD
(215) 955-3405

or Clinical Director
Chengyuan Wu, MD
(215) 955-7000

Clinical Office Building (COB)
909 Walnut Street
Philadelphia, PA 19107

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