Accuracy of Optic Nerve Sheath Diameter Measurement From Ultrasound Videos Using an Image Analysis Algorithm Compared to Expert Measurement in Patients With Acute Brain Injury
Trial Snapshot
- Phase
- Not Applicable
- Status
- Completed
- Sponsor
- University of Michigan
- Enrollment
- 75
- Locations
- 1
- Primary Endpoint
- Expert measurement of Optic Nerve Sheath Diameter
Study Overview
Brief Summary
Optic Nerve Ultrasound (ONUS) is a promising non-invasive tool for the detection of raised Intracranial Pressure (ICP). Variability in the optimal Optic Nerve Sheath Diameter (ONSD) threshold corresponding to elevated ICP in multiple studies limits the value of ONUS in clinical practice. The investigators goal is to develop and validate an automated image analysis algorithm for standardization of ONSD measurement from ultrasound videos. Patients with acute brain injury requiring invasive ICP monitoring will undergo bedside ONUS, with blinded ONSD measurement by an expert investigator. The image analysis algorithm will then be used to measure ONSD and accuracy determined compared to the "reference standard" expert measurement.
Detailed Description
BACKGROUND:
A promising tool under investigation for the non-invasive estimation of ICP is Optic Nerve Ultrasound (ONUS). Raised ICP results in distension of the optic nerve sheath (ONS), a continuation of the dura mater. Ocular imaging, performed by clinicians using point-of-care ultrasound machines, can detect ONS distension behind the eye. A study conducted at the University of Michigan identified an ONS Diameter (ONSD) cutoff of >0.51cm as having 98% sensitivity and 91% specificity for the detection of intracranial hypertension, defined as ICP>25mmHg. The significant variation seen in the optimal ONSD threshold for identification of high ICP across several studies, however, greatly limits the practical application of this technique at the bedside. Much of this variation in the optimal ONSD threshold is likely related to technique, with variation in the margins used to define the ONS on acquired ultrasound images by different operators. The ONS, visible as a linear hypodense structure behind the eye can vary in its visualized dimension based on the angle and plane of insonation. Automated image analysis may permit standardization of ONSD measurement and thereby minimize interobserver variability.
SPECIFIC AIM:
The investigators goal is to develop a computer image-analysis algorithm to standardize measurement of the ONSD from ultrasound videos, and to validate against the reference standard of expert manual measurement of ONSD.
METHODS:
Study Design
- Study Type
- Observational
- Observational Model
- Cohort
- Time Perspective
- Prospective
Eligibility Criteria
- Ages
- 18 Years to — (Adult, Older Adult)
- Sex
- All
- Accepts Healthy Volunteers
- No
Inclusion Criteria
- •Admitted to an ICU in the University of Michigan with Acute Brain Injury
- •Age> 18 years
- •Invasive ICP monitor (external ventricular drain or intraparenchymal catheter) already in place for a clinical indication.
Exclusion Criteria
- •Pre-existing ocular pathology other than refractive error
- •Traumatic globe injury
- •Age < 18 years
- •Known pregnancy or subsequently discovered pregnancy after admission Prisoners
Outcomes
Primary Outcomes
Expert measurement of Optic Nerve Sheath Diameter
Time Frame: Day of enrollment
The primary endpoint for determination of accuracy of automated image analysis measurement of Optic Nerve Sheath Diameter (ONSD) will be ONSD measurement performed by an expert investigator with \>5 years experience with ONUS and ONSD measurement.
Secondary Outcomes
No secondary outcomes reported
Investigators
Venkatakrishna Rajajee
Clinical Associate Professor, Neurosurgery and Neurology Medical Director, Neurointensive Care
University of Michigan