Collaboration at UCSF Peripheral Nerve Center Helps Difficult-to-Diagnose Patient

The Peripheral Nerve Center at UCSF is comprised of a multidisciplinary team devoted to precisely assessing and addressing often painful and difficult-to-diagnose conditions of the peripheral nervous system. The Precision Spine Center run by the neuroradiology section of the Department of Radiology and Biomedical Imaging collaborates closely with the Peripheral Nerve Center and is one of the only centers in the world that routinely offers high-resolution imaging techniques including MR neurography as well as CT, MR and ultrasound image guided injections.

One patient who was eventually diagnosed with thoracic outlet syndrome, was in constant pain and bed-ridden for 18 months unable to work or take care of himself. "It was so demoralizing going from a healthy athlete to disabled with no medical diagnosis or treatment plan," the patient wrote in an email to Associate Professor and Chief of Neuroradiology Vinil Shah, MD.

This patient was eventually diagnosed, and treated, at the UCSF Precision Spine and the Peripheral Nerve Center, for neurogenic thoracic outlet syndrome, a condition in which there is entrapment of nerves of the brachial plexus in the neck. Using sonographic guidance Dr. Shah gave this patient Botox injections into the anterior and middle scalene muscles.

"The scalene Botox treatment has worked like a miracle and has given my life back. I am pain free and back to 90-95% function. I am working, surfing and rock-climbing after eight months from my first Botox," the patient said in an email.

It is patients like these — difficult to assess and therefore treat — that the Peripheral Nerve Center's team of neuroradiologists, US and MSK radiologists, neurosurgeons, neurologists, orthopedic surgeons and pain physicians are working to help.

"The impact on patients is dramatic," Dr. Shah said. "These patients would not have many places to go — even many other major academic medical centers are not able to offer the degree of expertise and image interpretation."

The peripheral nerves, which reside throughout the entire body outside the brain and spinal cord, are often a few millimeters or less in size. Although there have been major advances in understanding the anatomy and impact of these tiny nerves, they still remain somewhat of an enigma to many in the medical community. For patients with peripheral nerve disorders or injuries, getting an accurate diagnosis and effective treatment can be challenging.

Professor of Clinical Radiology and Neurosurgery Cynthia Chin, MD, along with Professor of Neurology John Engstrom, MD, and Professor Emeritus Philip Weinstein, MD, Department of Neurological Surgery, developed the protocols for the nerve imaging techniques and sequences used at UCSF over a period of more than 20 years.

MR neurography allows clinicians to see the anatomy of the peripheral nerves in various parts of the body in exclusive detail, which provides essential information about whether the nerve is injured so that the neurologists and surgeons can diagnose a problem and figure out a plan for treatment, said Dr. Chin. "It took many years to develop it to be a routine study that we now do every day," Dr. Chin said. About 25 patients per week undergo these advanced imaging studies at UCSF.

During MR neurography the fat signal prevalent in muscle and bone is suppressed — so the nerve signal becomes more conspicuous. "If you're trying to find a needle in a haystack, make the haystack all one color" and disappear into the background so you can see the needle, Dr. Chin said.

Diffusion tensor imaging is another MR technique that explores the integrity of the nerve in even greater detail - tracking the movement of the water within nerve fibers, allowing physicians to look at the ultrastructure of the nerves and to characterize the organization of the axons within the peripheral nerve. Physicians then create a 3D reconstruction, or tractography of the nerve, which indicates if the nerve fibers are intact or disrupted.

"We can also indirectly measure the speed of the water movement going up and down along the nerve fibers," Dr. Chin said. "If there's a tumor or injured nerve, water motion will be abnormal, and may be relatively reduced or increased depending upon the degree of tumor cellularity, stage of injury and treatment. We can measure this water motion activity and give the physicians taking care of the patient some indication of what might be going on."

"When it comes to imaging, MR neurograms aren't difficult to obtain, but are exceptionally difficult to read well," Dr. Engstrom said. "We have a concentration of expertise in one place, which can be leveraged onto diagnostic problems that folks have been stumped by."

Through the training provided in the Neuroradiology fellowship program, the next generation of radiologists are also learning to interpret these highly specialized studies.

Professor of Neurological Surgery Line Jacques, MD, regularly refers patients for advanced peripheral nerve imaging. "These advanced images allow us to act faster, wait times for an intervention can be reduced by 2-3 weeks," Dr. Jacques said. For example, if the MR neurogram indicates a laceration of a peripheral nerve, Dr. Jacques can schedule surgery immediately, rather than waiting several weeks.

Professor of Radiology William P. Dillon, MD, has been working as a neuroradiologist for over 35 years. He says the Precision Spine and the Peripheral Nerve Center represents a shift toward greater precision in radiology. "When I was training, we did not have the tools to interrogate the peripheral nerves," Dr. Dillon said, "Now it's routine."

Dr. Dillon recently saw a patient who had a cystic lesion around an upper thoracic nerve root and had pain in the shoulder and back area. "We noticed she had a little mass near her chest along a nerve root that hadn't been recognized before. We're going to work that up to make sure that's not the cause of her pain."

"The ability to see in different parts of the body and then precisely place needles for diagnosis or therapeutic injections into very sensitive areas is a real advantage," Dr. Dillon said.

Dr. Shah said he enjoys working with referring clinicians to improve the health of these often difficult-to-diagnose patients. "It's very satisfying to be able to identify the diagnosis and try to help them."