The cutting-edge applications of ultrasound in neurology

Imaging is central to neurological practice. It doesn’t take much to tempt a neurologist to ‘order’ or ‘request’ an MRI or a CT. In appropriate circumstances the imaging is a DAT scan, and with a bit more savvy, exciting imaging modalities such as amyloid scans and tau PET scans. In the playpen of the neurologist, the more ‘high tech’ the imaging technology, the more cutting-edge it feels-even if it doesn’t make much of a difference to the patient. Ultrasound on the other hand is the mongrel of imaging technologies. Too simple, too cheap, too available, too unsophisticated-not better than good old X-rays. It is safe to assume that the pen of the neurologist hardly ever ticks the ultrasound box. What for?

prd brain scan. Patrick Denker on Flickr. https://www.flickr.com/photos/pdenker/74684051

And yet, ultrasound has an established, even if poorly appreciated, place in neurological imaging. It is perhaps best known for its usefulness in assessing carpal tunnel syndrome at the wrist. But, for the neurologist, CTS is sorted out by wrist splints, steroid injections, and decompression surgery-forgetting that there may just be a ganglion, a cyst, or a lipoma lurking in there. Ultrasound also has a place in the assessment of muscle disorders, picking up anomalies and detecting distinctive muscle disease patterns. The only problem is that, even when radiologists and neurologists put their heads together, they struggle to understand what the patterns actually mean. So, for many reasons, the ultrasound box remains un-ticked.

By RSatUSZ – PACS UniversitätsSpitalZürich, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=11272585

Despite these limitations, the place of ultrasound remains entrenched in neurological practice. Indeed, ultrasound has been spreading its wings to exotic places, broadening its range, and asserting its presence. Perhaps it is time to reconsider the humble ultrasound, and to catch up with what it has been up to. Here then are 5 emerging roles of ultrasound in neurology

Therapeutic ultrasound

The role of ultrasound in treatment is reviewed in the excellent paper in Nature Neurology titled Ultrasound treatment of neurological diseases-current and emerging applications. And the emphasis is on trans-cranial MR-guided focused ultrasound (tcMRgFUS). tcMRgFUS is making waves in the treatment of essential tremor (ET), Parkinson’s disease (PD), and central pain. The benefit for PD is already filtering out into the popular press such as this article in STAT titled New treatment offers some hope for an unshakable tremor. Ultrasound is also rapidly emerging as an option in the ablation of brain tumours, and in the treatment of stroke (sonothrombolysis). 

By Images are generated by Life Science Databases(LSDB). – from Anatomography, website maintained by Life Science Databases(LSDB).You can get this image through URL below. https://commons.wikimedia.org/w/index.php?curid=7845026

Drug delivery into the brain

The blood brain barrier is a rigidly selective barricade against most things that venture to approach the brain-even if their intentions are noble. This is a huge impediment to getting drugs to reach the brain where they are badly needed. It is therefore humbling that it is the simple ultrasound that is promising to smuggle benevolent drugs across the blockade to aid afflicted brains. This was reported in the journal Science Translational Medicine, and the article is titled Clinical trial of blood-brain barrier disruption by pulsed ultrasound. The trial subjects were people with the notorious brain tumour, glioblastoma. They were injected with their conventional chemotherapy drugs, delivered along with microbubbles. The blood brain barrier was then repeatedly ‘pelted’ with pulsed ultrasound waves; this seem to leapfrog the drugs into the brain in greater than usual concentrations, enough to do a much better job. This surely makes films such as Fantastic Voyage and Inner Space not far-off pipe-dreams.

Bubbles. Jeff Kubina on Flickr. https://www.flickr.com/photos/kubina/153871892

Treatment of coma

Some of the emerging neurological applications of ultrasound are even more Sci-Fi than pulsed ultrasound. And a sign of this Sci-Neuro world is this report titled UCLA scientists use ultrasound to jump-start a man’s brain after coma. One is tempted to dismiss this as ‘fake news’ but it is a proper case report, in a proper scientific journal, Brain Stimulation, and with a proper scientific title, Non-Invasive Ultrasonic Thalamic Stimulation in Disorders of Consciousness after Severe Brain Injury: A First-in-Man Report. By targeting ultrasounds to the subject’s thalamus, the authors assert, the subject just woke up (and presumably asked for a hot cup of tea!). A word of caution is however needed; the authors rightly point out that it may have all been…coincidental!

The awakening (arm). Jeff Kubina on Flickr. https://www.flickr.com/photos/kubina/153871892

Ultrasound is clearly humble no more.

Big ambition trumps humble beginnings.

from The Neurology Lounge https://ift.tt/3eOzWDv