High-Resolution Diffusion MRI Can Help Map the Microstructure of the Trigeminal Nerve, Improve Treatment Options for Trigeminal Neuralgia Sufferers

Newswise — NEW ORLEANS (May 1, 2013) — Today during the 81st American Association of Neurological Surgeons (AANS) Annual Scientific Meeting, researchers described their study regarding the use of high-resolution diffusion MRI to evaluate the microstructure of the cranial nerves.

The researchers noted that the pathophysiology of trigeminal neuralgia (TN) remains unknown and present treatments are conducted based on empirical evidence. Up to now, MRI has only been used to exclude other pathological conditions such as skull base tumors — which can mimic TN — but not to localize the affected area, improve treatment methods or evaluate the effects of such procedures.

For the study, researchers sought out to demonstrate the feasibility and advantages of ultra-high field diffusion MRI at the skull base, which could lead to improved TN characterization. Healthy volunteers were scanned on a 7T Siemens scanner with the following protocol: T1-, T2- and PD-weighted structural MRI with resolution 0.3x0.3x0.6mm3; diffusion MRI with 0.6x0.6mm2 in-plane resolution, 18 slices of 1.2mm, 100 gradient directions at b-value=1000s/mm2, 11 non-diffusion-weighted images, and TR/TE=5000/64ms. The results of this study, High-Resolution diffusion MRI of the Trigeminal Nerve using 7T MRI, will be presented by Andrew Grande, MD, from 12:06-12:17 p.m. on Wednesday, May 1. Co-authors are Christophe Lenglet, PhD; Julien Sein, PhD; Julian Tokarev; Bharathi Jagadeesan, MD; and Pierre-François Van de Moortele, MD, PhD.

The researchers’ imaging protocol generated high-resolution FA and ADC maps, as well as fiber orientation estimates successfully used to characterize the microstructure of the trigeminal nerve and its divisions at the skull base using deterministic and probabilistic tractography algorithms. The researchers concluded that their findings open up new possibilities for further understanding of the pathophysiology of TN, with the prospect of improving treatments based on this new knowledge.

“Trigeminal neuralgia is a rare disease with only 150,000 new cases per year, and has been described as perhaps the worse pain imaginable. Most patients experience shock or lightning-like shocks in their face triggered by various stimuli such as eating, wind, brushing teeth or just simply talking. Patients fear this stimuli and consequently avoid eating, or going outside or talking,” said Andrew Grande, MD. “In this study, we have investigated the feasibility and advantages of ultra-high field magnetic resonance imaging (MRI), at 7 Tesla, of the skull base. 7T MRI, by comparison with clinical imaging typically performed at 1.5T or 3T, provides greater image resolution and contrast, thereby improving our ability to identify and assess the integrity of structures like the trigeminal nerve. More specifically, we have focused on high-resolution diffusion MRI, which characterizes the three-dimensional configuration and microstructural properties of axonal pathways. This work opens new and exciting possibilities to further our understanding of the pathophysiology of trigeminal neuralgia and, ultimately, improve available treatments. In the future, in addition to aiding our understanding of the pathophysiology of trigeminal neuralgia, such imaging may allow us to better diagnose and could potentially be used to guide some forms of treatment directly to the afflicted portion of the nerve.”

Disclosure: The author reported no conflicts of interest.

Media Representatives: The 2013 AANS Annual Meeting Press Kit includes releases on highlighted scientific research, AANS officer and award winners, National Neurosurgery Awareness Week, and other relevant information about this year’s program. Those releases also will be posted under the Media area on the 2013 AANS Annual Scientific Meeting website (http://www.aans.org/Annual Meeting/2013/Main/Media.aspx). If you would have interest in a topic related to neurosurgery or would like to interview a neurosurgeon — either on-site or via telephone — during this year’s event, please contact John Iwanski, AANS Director of Member and Public Outreach, via the onsite press room at (504) 670-4910 or e-mail him at [email protected].

About the 2013 AANS Annual Scientific Meeting: Attended by neurosurgeons, neurosurgical residents, medical students, neuroscience nurses, clinical specialists, physician assistants, allied health professionals and other medical professionals, the AANS Annual Scientific Meeting is the largest gathering of neurosurgeons in the nation, with an emphasis on the field’s latest research and technological advances. A record-breaking 1,003 scientific abstracts were presented for review at the 2013 AANS Annual Scientific Meeting, and the scientific presentations given at this year’s event represent cutting-edge examples of the incredible developments taking place within the field of neurosurgery. Additional information about the AANS Annual Scientific Meeting and the Meeting Program can be found at http://www.aans.org/Annual Meeting/2013/Main/Home.aspx.

Founded in 1931 as the Harvey Cushing Society, the American Association of Neurological Surgeons (AANS) is a scientific and educational association with nearly 8,300 members worldwide. The AANS is dedicated to advancing the specialty of neurological surgery in order to provide the highest quality of neurosurgical care to the public. All active members of the AANS are certified by the American Board of Neurological Surgery, the Royal College of Physicians and Surgeons (Neurosurgery) of Canada or the Mexican Council of Neurological Surgery, AC. Neurological surgery is the medical specialty concerned with the prevention, diagnosis, treatment and rehabilitation of disorders that affect the entire nervous system including the spinal column, spinal cord, brain and peripheral nerves. For more information, visit www.AANS.org.