Point-of-care ultrasound for detecting elevated intracranial pressure in the field

Transcription

1 Point-of-care ultrasound for detecting elevated intracranial pressure in the field Stephen Aylward, Ph.D. 1, Sam Gerber, Ph.D. 1, Maeliss Jallais 1, Matt McCormick, Ph.D. 1 Sean Montgomery, M.D. 2 Luv Kohli, Ph.D. 3 Bradley Freeman, M.D. 4, Deborah Shipley Kane, M.D. 5 1 Kitware, Inc., Carrboro, NC 2 Surgery, Duke University Medical Center, Durham, NC 3 InnerOptic, Hillsborough, NC 4 Surgery and 5 Emergency Medicine, Washington Univ. School of Medicine; St. Louis, MO Disclosure Kitware is a scientific software consulting company Grant-funded, open-source software research and commercial consulting This research and open-source software was funded, in part, by NIH/NIGMS/NIBIB: Slicer+PLUS: Collaborative, open-source software for ultrasound analysis (R01EB Ongoing) 1

2 Outline Point-of-Care Ultrasound Elevated ICP and Optic Nerve Sheath Diameter (ONSD) Automated ONSD Estimation Phantom Experiments Retrospective Study Problem being addressed Far-forward, medical personnel lack portable, easy-to-use diagnostic devices to detect intra-abdominal bleeding (IAB), pneumothorax (PTX), or traumatic brain injury (TBI). Point-of-care ultrasound in the hands of highly trained experts is accurate for the diagnosis of these conditions. When in-field ultrasound is conducted by experts, patient management is altered in 37% of cases. [Walcher 2002] Even after hours of training, pre-hospital personnel are not sufficiently proficient in FAST for over 48% of trauma patients. [Melanson 2001] 2

3 Point-of-Care Ultrasound (POCUS) Critical needs for POCUS to have impact Rugged, compact, portable hardware Intuitive Automated image analysis Application-specific interfaces Guidance for position and data quality (sufficient gel?) Output = Diagnostic info (Red light / Green light) B-mode images POCUS Equipment and Applications TBI (Intracranial pressure) FAST Pneumothorax Hemothorax Renal dysfunction BladderScan Interson USB Probes FAST Exam PTX Guidance: paracentesis, peripheral vascular access 3

4 POCUS Equipment and Applications TBI (Intracranial pressure) FAST Pneumothorax Hemothorax Renal dysfunction BladderScan Interson USB Probes FAST Exam PTX Guidance: paracentesis, peripheral vascular access Optic Nerve Sheath Diameter (ONSD) correlates with ICP Ultrasonographic measured optic nerve sheath diameter as an accurate and quick monitor for changes in intracranial pressure. Maissan IM, Dirven PJ, Haitsma IK, Hoeks SE, Gommers D, Stolker RJ J Neurosurg Sep;123(3): ICP-monitored patients in ICU Before, during, and after tracheal manipulation to increase ICP ICP above 20 mmhg is associated with dilation of ONSD > 5.0mm mmhg = mild intracranial hypertension 94% sensitivity 98% specificity From crashingpatient.com 4

5 Automated ONSD Estimation 1. Apply gel 2. Perform sweeping motions over eye 3. System analyzes 4 images per second: 1. Reports if there is insufficient gel 2. Identifies the orbit and optic nerve 3. Estimates ONSD at 3mm from orbit 4. Reports maximal ONSD estimates Automated ONSD Estimation 1. Apply gel 2. Perform sweeping motions over eye 3. System analyzes 4 images per second: 1. Reports if there is insufficient gel 2. Identifies the orbit and optic nerve 3. Estimates ONSD at 3mm from orbit 4. Reports maximal ONSD estimates 5

6 Automated ONSD Estimation Find the center of the big dark blob 2. Warp a circle to fit the edges of that blob 3. Use that warped circle to define a region of interest, where the optic nerve should be. 4. Find the center of the dark column 5. Warp the column to fit the edges Exp. 1: Phantom Study Gelatin phantom [Zeiler 2014] 3D-printed optic nerves From [Zeiler 2014] 6

7 Exp. 1: Phantom Study Disc size Estimated Mean Estimated Lower Quartile Upper Quartile 7 mm mm mm mm mm Human observer study 23 images Compared to an expert R 2 = 0.91 p-value = 2.0e-12 Compared with mean of others Auto R 2 = 0.82 Expert R 2 = 0.84 Med. students R 2 =

8 Point-of-Care Ultrasound (POCUS) Critical needs Rugged, compact, portable hardware Intuitive Automated image analysis Application-specific interfaces Output = Diagnostic info Multiple diagnostic tests from a single device FAST Poster #3 PTX FAST Exam Point-of-care ultrasound for detecting elevated intracranial pressure in the field Stephen Aylward, Ph.D. 1, Sam Gerber, Ph.D. 1, Maeliss Jallais 1, Matt McCormick, Ph.D. 1 Sean Montgomery, M.D. 2 Luv Kohli, Ph.D. 3 Bradley Freeman, M.D. 4, Deborah Shipley Kane, M.D. 5 1 Kitware, Inc., Carrboro, NC 2 Surgery, Duke University Medical Center, Durham, NC 3 InnerOptic, Hillsborough, NC 4 Surgery and 5 Emergency Medicine, Washington Univ. School of Medicine; St. Louis, MO 8