Meaghan O'Reilly

Research Synopsis

Therapeutic Applications of Ultrasound

Ultrasound is an exciting therapeutic modality due to its ability to focus thermal and mechanical effects deep in the body while sparing intervening tissue. Because it is non-ionizing and can be precisely targeted it is particularly well suited for targets in or near sensitive structures. My research career to date has focused on developing systems and methods to deliver, monitor and control ultrasound therapy in the brain. My current research interests include adapting these methods, and developing new ones, for ultrasound applications in the spine.

Examples of ongoing projects:

• Targeted Drug Delivery to the Spinal Cord: The brain and spinal cord have protective barriers that regulate their environment, but also restrict the ability of drugs to reach these tissues. In the spinal cord, this makes conditions like Amyotrophic Lateral Sclerosis, Spinal Muscular Atrophy, spinal cord injury and cancerous involvement of the spinal cord challenging to treat with drug therapies. These barriers can be transiently opened using ultrasound to facilitate drug, cell and gene therapies. This is accomplished when the ultrasound interacts with micro-sized gas spheres that are injected in the blood stream and causes them to vibrate, stimulating the blood vessel walls. My group is experimentally investigating spinal cord-specific methods and applications for targeted drug delivery.
• Extracorporeal Ultrasound Delivery to the Spine: Despite some very promising applications in the spine, a limited amount of work has been done in this area due to the technical challenges associated with delivering ultrasound through complex bone structures, such as the vertebrae. The speed of sound in bone can be over twice that in soft tissue, and varies significantly with bone density. Thus, ultrasound propagating through bone undergoes location specific variations in speed, which have an aberrating effect on the focus. We are using computational and experimental methods, and building on techniques used for transcranial and transcostal ultrasound, to develop an approach for delivering ultrasound through the intact human spine.

Recent Publications

• Weber-Adrian D, Thévenot E, O'Reilly MA, et al., Gene delivery to the spinal cord using MRI-guided focused ultrasound. Gene Ther. 2015; 22(7):568-77
• O’Reilly MA, Jones RM, Hynynen K. Three-dimensional transcranial ultrasound imaging of microbubble clouds using a sparse hemispherical array. IEEE Trans Biomed Eng. 2014;61(4):1285–1294.
• O'Reilly MA, Hynynen K. A super-resolution ultrasound method for brain vascular mapping. Medical Physics. 2013;40(11):110701.
• O’Reilly MA, Hynynen K. Blood-brain barrier: Real-time feedback-controlled focused ultrasound disruption by using an acoustic emissions-based controller. Radiology. 2012;263(1):96–106.
• O’Reilly MA, Hynynen K. Ultrasound enhanced drug delivery to the brain and central nervous system. Int J Hyperthermia. 2012;28(4):386–396
• O’Reilly MA, Huang Y, Hynynen K. The impact of standing wave effects on transcranial focused ultrasound disruption of the blood-brain barrier in a rat model. Phys Med Biol. 2010;55(18):5251–5267.

Graduate Students

Andrew Frizado
David Martin
Mahsa Mokhlesabadi
Paige Smith